FR3064143A1 - ELECTRONIC ENGINE CONTROL MODULE FOR A MOTOR VEHICLE COMPRISING A MICROCONTROLLER AND A STEERING MODULE - Google Patents

Abstract

The invention relates to an engine control electronic module (MCO) for a motor vehicle comprising a microcontroller (MC) and a control module (D) adapted to communicate together via a monofilar serial link (L), according to which: - said microcontroller ( MC) comprises a reception input (ERx) and a transmission output (STx) connected to said reception input (ERx) so that when a request (REQ) is transmitted on said transmission output (STx) by said microcontroller (MC), it is also received on said reception input (ERx); said microcontroller (MC) is adapted to send a request (REQ) to said control module (D), to receive information (INF) from said control module (D), and to detect a collision on said monofilar serial link (L) - Said control module (D) is adapted to receive a request (REQ) of said microcontroller (MC) and send information (INF) to said microcontroller (MC).

Description

TECHNICAL FIELD OF THE INVENTION

The present invention relates to an electronic engine control module for a motor vehicle comprising a microcontroller and a control module adapted to communicate together via a single-wire serial link. It also relates to a communication method implemented by said electronic engine control module.

It finds a particular, but not limiting, application in air blowers for heating, ventilation and / or air conditioning devices for motor vehicles.

TECHNOLOGICAL BACKGROUND OF THE INVENTION

An electronic engine control module known to those skilled in the art includes:

- a microcontroller suitable for transmitting a request to the control module and receiving information from the control module;

- a control module adapted to respond to a request from the microcontroller and transmit information on request or spontaneously to the microcontroller.

The microcontroller and the control module communicate via a single communication line (also called transmission-reception line), namely a single-wire serial link. So that the microcontroller and the control module can respectively transmit requests and information in turn without risk of collision, a line monitoring module is used, the latter being generally included in the microcontroller.

A disadvantage of this state of the art is that when there is no line monitoring module or that it is used by other resources to monitor other communication lines, there may be collisions on the monofilament serial link when the control module spontaneously transmits information to the microcontroller while the latter simultaneously transmits a request to it.

In this context, the present invention aims to solve the aforementioned drawback.

GENERAL DESCRIPTION OF THE INVENTION

To this end, the invention proposes an electronic engine control module for a motor vehicle comprising a microcontroller and a control module adapted to communicate together via a single-wire serial link, according to which:

- said microcontroller comprises:

- a reception entrance;

- a transmission output connected to said reception input so that when a request is transmitted on said transmission output by said microcontroller, it is also received on said reception input;

- a reception buffer;

- a transmission butter;

- said microcontroller is suitable for:

- send a request to said control module and receive information from said control module via said single-wire serial link;

- detecting a communication error or a data error including a collision on said single-wire serial link, said collision detection comprising a comparison of said transmission butter and said reception buffer when said reception input receives a request;

- said control module is suitable for:

- receive a request from said microcontroller via said single-wire serial link;

- send information to said microcontroller via said single-wire serial link.

(Note that the term "butter" or "buffer" can be used interchangeably)

According to nonlimiting embodiments, the electronic engine control module can also include one or more additional characteristics among the following:

According to a nonlimiting embodiment, said information includes a state of said control module. This allows you to know whether the control module has a fault or not.

According to a nonlimiting embodiment, said information is information sent by said control module on request or not from said microcontroller. Thus, the control module can send information on request or spontaneously. As soon as he has a fault, he can send his status without the microcontroller asking him.

According to a nonlimiting embodiment, a primary duration is defined between a transmission of a request from said microcontroller to said control module and a reception of information by said microcontroller, information sent by said control module following said request. The primary duration thus represents a delay which limits in time an exchange between the microcontroller and the control module.

According to a nonlimiting embodiment, a primary counter is incremented when a collision is detected. This allows the previously issued request to be re-emitted or not.

According to a nonlimiting embodiment, said microcontroller is further adapted to re-issue a request previously sent to said control module if a collision is detected. Thus, if the collision was only punctual, the request is re-emitted so as to ultimately receive the state of the control module.

According to a nonlimiting embodiment, said microcontroller is further adapted to re-issue a request previously sent to said control module in the event of no sending of information in said primary duration of said control module following a request sent by said microcontroller to said control module. Thus, if the non-response was only punctual, the request is re-emitted so as to ultimately receive the state of the control module.

According to a nonlimiting embodiment, a secondary counter is incremented if the primary counter is equal to two. If a communication or data error (such as a collision or lack of information sent by the control module in the primary duration) occurs more than once, we wait for a certain time to see if it will last or not. We wait for a given period.

According to a nonlimiting embodiment, said microcontroller is further adapted to execute a determined action if the secondary counter reaches a predetermined value. If the communication or data error is recurrent, we can in a nonlimiting example reset the electronic control module.

According to a nonlimiting embodiment, said microcontroller is further adapted to check whether it has received information from said control module over a period. This makes it possible to regularly check whether the control module has not sent a fault (via its state) spontaneously.

According to a nonlimiting embodiment, said electronic engine control module is suitable for controlling a motor for an air blower for a heating, ventilation and / or air conditioning device.

There is also proposed a method of communication between a microcontroller and a control module of an electronic engine control module via a single-wire serial link, according to which said microcontroller comprises:

- a reception entrance;

- a transmission output connected to said reception input so that when a request is transmitted on said transmission output by said microcontroller, it is also received on said reception input;

- a reception buffer;

- a transmission butter;

said communication method comprising:

- transmission of a request by said microcontroller to said control module via said single-wire serial link;

a detection by said microcontroller of a communication error or a data error, including a collision on the single-wire serial link, said collision detection comprising a comparison of said transmission butter and said reception buffer when said input receiving receives a request;

- reception of said request by said control module via said single-wire serial link;

- if no communication or data error is detected, a sending by said control module of information to said microcontroller and a reception by said microcontroller of information from said control module via said single-wire serial link.

According to non-limiting embodiments, the communication method can also include one or more additional characteristics among the following:

According to a nonlimiting embodiment, said information includes a state of the control module.

According to a nonlimiting embodiment, a primary duration is defined between a transmission of a request from said microcontroller to said control module and a reception of information by said microcontroller, information sent by said control module following said request.

According to a nonlimiting embodiment, a primary counter is incremented when a collision is detected.

According to a nonlimiting embodiment, said communication method further comprises a retransmission by said microcontroller of a request previously sent to said control module if a collision is detected.

According to a nonlimiting embodiment, a secondary counter is incremented if the primary counter is equal to two.

According to a nonlimiting embodiment, said communication method further comprises a verification by said microcontroller if it has received information from said control module over a period.

BRIEF DESCRIPTION OF THE FIGURES

The invention and its different applications will be better understood at the

reading the description who follows and on the exam figures who accompany him - Figure 1 represented a diagram of a module electronic of ordered motor including a microcontroller and a module of

piloting according to a nonlimiting embodiment of the invention;

- Figure 2 shows a flowchart of a communication method implemented by said electronic engine control module of Figure 1 according to a non-limiting embodiment.

DESCRIPTION OF EMBODIMENTS OF THE INVENTION

Identical elements, by structure or by function, appearing in different figures keep, unless otherwise specified, the same references.

The electronic engine control module MCO for a motor vehicle is described with reference to FIG. 1 according to a nonlimiting embodiment.

By motor vehicle is meant any type of motor vehicle.

In a nonlimiting embodiment, the electronic motor control module MCO is suitable for controlling a motor for a PUL air blower.

In a nonlimiting embodiment, the PUL air blower comprises said electronic engine control MCO module. In another nonlimiting embodiment, said electronic engine control module MCO is remote.

In a nonlimiting embodiment, a PUL air blower is used in an air conditioning, ventilation and / or heating device, known in English as HVAC "Heating Ventilation and Air-Conditioning" for a motor vehicle. In the following description, the heating, ventilation and / or air conditioning device will also be called an HVAC device.

Note that a PUL air blower includes:

- an electric motor adapted to be powered by a driving load, said driving load making it possible to turn the motor of the PUL blower;

- a centrifugal type wheel mounted on an axis of the electric motor;

- an engine support in which the electric motor is housed.

The PUL air blower is suitable for:

- receive air flow instructions; and

- send diagnostic information. In nonlimiting examples, this diagnostic information indicates short-circuits, over-voltages, under-voltages, over-temperatures, faulty equipment, the power consumption of the air blower, etc.

All of these elements are configured to be mounted in a device

HVAC through said engine mount.

Since such blowers are known to those skilled in the art, they are not described in detail here.

As illustrated in FIG. 1, the electronic engine control module MCO comprises:

- a microcontroller MC adapted to transmit a REQ request to a control module D and receive information INF from said control module D;

a control module D adapted to respond to a REQ request from said microcontroller MC and to transmit, on request or without request, information INF to the microcontroller MC. The control module D is called "driver" in English.

In a nonlimiting embodiment, said microcontroller MC and said control module D are part of the same printed circuit board called PCBA ("Printed Circuit Board Assembly" in English).

The microcontroller MC is further adapted to receive an air flow setpoint at the input and provide the control module D at output with a current for a control element, the latter being adapted to control a driving load of the PUL air blower. .

Said microcontroller MC and said control module D are adapted to communicate together via a single-wire serial link L.

In a nonlimiting embodiment, the communication between the microcontroller MC and the control module D takes place at 9600 bauds.

The single wire serial link L is a bidirectional serial link. In a nonlimiting embodiment, the single-wire serial link L is an RS232 link well known to those skilled in the art.

The microcontroller MC and said control module D are adapted to communicate asynchronously. Thus, one can send a REQ request while the other sends INF information at the same time or vice versa.

On the single-wire serial link L, a collision Co is therefore possible, in particular in the case where the control module D sends request information INF to the microcontroller MC while the microcontroller MC on its side sends a REQ request to said module piloting D.

Thus, two cases of Co collisions can arise:

the control module D transmits information INF without knowing that the microcontroller MC is in the process of transmitting a REQ request;

the microcontroller MC transmits a REQ request without knowing that the control module D is in the process of transmitting information INF.

The elements of the electronic engine control module MCO are described in detail below.

• Control module.

Control module D is suitable for:

- send information INF to said microcontroller MC via the monofilament serial link L at the request of said microcontroller MC or not (function illustrated in FIG. 1 TX (D, MC, INF (STAT));

- receive a REQ request from said MC D microcontroller via said single wire serial link L (function illustrated in FIG. 1 RX (D, MC, REQ)).

In a nonlimiting embodiment, the information INF includes a STAT state of the control module D.

A STAT state thus makes it possible to indicate whether or not there is a fault on the control module D. In nonlimiting examples, this fault is a short circuit, an overvoltage, an undervoltage, an over temperature, a electronic component of the control module D faulty, a rise in temperature, etc.

We speak of information requested INFs by said microcontroller MC when it is sent by said control module D on the initiative of the microcontroller MC, or unsolicited information INFu by said microcontroller MC when it is sent by said module piloting D spontaneously without any request from said microcontroller MC. The unsolicited information INFu is so-called asynchronous information.

Unsolicited information INFu is sent by the control module D as soon as a fault in said control module D appears. The control module D thus sends a new STAT state which is decoded by the universal asynchronous transceiver UART of the microcontroller MC.

In a nonlimiting embodiment, the control module D comprises two states STAT referenced STAT1 and STAT2. This makes it possible to code the various faults which may arise. It will be noted that when a STAT state is sent by the control module D to the microcontroller MC, this STAT state is saved in the state register Fteg_STAT of its universal asynchronous transceiver UART.

In a nonlimiting embodiment, a STAT state is coded on an 8-bit byte. Thus, in a nonlimiting embodiment, the information INF is transmitted on at least one 8-bit byte (bit 0 to bit 7) framed by a start bit and an end bit.

A first byte includes a response which is a call back to a REQ request received from the microcontroller MC and a second byte includes data in response to said REQ request, if data is required. In a nonlimiting example, in the first byte:

- the most significant bit bit 7 is equal to 0;

- the first four bits bit 0 to bit 4 are reserved for coding the command.

In a nonlimiting embodiment, the information INF includes:

- an ACK confirmation bit (bit 6 = 1 in non-limiting example);

- a NACK non-confirmation bit adapted to indicate that the request

REQ is not supported or that the request has generated an error (bit 6 = 0 in nonlimiting example);

- bits for the STAT state.

The control module D is further adapted to control at least one control element as a function of the air flow setpoints sent to the PUL air blower. It is thus suitable for sending signals to the control element, the latter interpreting these signals so as to control the driving loads. At least one control element is associated with the driving load to drive the current in said at least one driving load. In a nonlimiting embodiment, the control element is a MOSFET transistor. This control being well known to a person skilled in the art, it is not described here.

• MC controller

The microcontroller MC is adapted to communicate with the control module D. To this end, the microcontroller MC is suitable for:

- send a REQ request to a control module D via said single-wire serial link L (function illustrated in FIG. 1 TX (MC, D, REQ));

- receive information INF from said control module D via said single-wire serial link L (function illustrated in FIG. 1 RX (MC, D, INF (STAT))).

The MC microcontroller is also suitable for:

- detect a Com_Err communication error or a Dat_Err data error (function illustrated in Figure 1 CHK_ERR (Com_Err, Dat_Err))) including a Co collision which occurs on the single-wire serial link L;

- check whether it received from said control module D information INF (said information comprising a STAT state) (function illustrated in FIG. 1 CHK_UNSOLL_STAT (STAT));

The Com_Err communication error or Dat_Err data error detection function includes:

- a sub-function for detecting a communication error illustrated in FIG. 1 DETCT_ComErr;

- a data error detection sub-function illustrated in FIG. 1 DETCT_DatErr, this sub-function itself comprising a collision detection sub-function Co illustrated in FIG. 1 DETCTCO.

As illustrated in FIG. 1, the microcontroller MC includes:

- a universal asynchronous UART transceiver comprising:

- an ERx reception input;

- an STx transmission output connected to said ERx reception input;

- a primary FIFORx buffer memory, also called reception buffer memory;

- a FIFOTx secondary buffer memory, also called transmission buffer memory;

- a Fteg_STAT state register;

- a BUFFTx transmission butter;

- a BUFFRx acceptance receipt;

- a memory location STAT_MEM to save a STAT state of said control module D;

- PN_E / S input / output pins.

Said universal asynchronous transceiver UART is a resource (also called peripheral) of the microcontroller MC.

The microcontroller MC further comprises a processing unit UT which is adapted to carry out the above communication, error detection and verification functions. More particularly, it is suitable for executing a computer program product embedded in a non-volatile memory. In a nonlimiting example, this non-volatile memory is a non-volatile non-rewritable memory ROM ("Read Only Memory" in English).

The communication, error detection, and verification functions are described below.

o Communication

Note that a REQ request to be sent is saved in the BUFFTx transmission butter before being copied into the FIFOTx secondary buffer for transmission.

Note that INF information received is copied from the FIFORx primary buffer for reception and saved in the BUFFRx reception butter.

In a nonlimiting embodiment, a REQ request is transmitted on at least one 8-bit byte each framed by a start bit and an end bit.

A first byte includes a command and a second byte includes data associated with said command, if data is required. In a nonlimiting example, in the first byte:

- the most significant bit bit 7 is equal to 1;

- the first four bits bitO to bit4 are reserved for coding the command;

- bit 5 and bit 6 are reserved for future uses.

In nonlimiting embodiments, the REQ request is:

- a GET_STAT state command to recover a STAT state of the control module D;

- a SET_CFG configuration command of the control module D.

It will be noted that when the microcontroller MC communicates with the control module D, there is a PHJNIT initialization phase.

In a nonlimiting embodiment, this PHJNIT initialization phase comprises the transmission by the microcontroller MC of five REQ requests to the control module D including three configuration commands SET_CFG and two state commands GET_STAT. The three SET_CFG configuration commands are used to configure the configuration registers of the control module D. The two GET_STAT state commands are used to recover the two states STAT1 and STAT2 of the control module D. Note that these five REQ requests are also sent when there is a reset of the entire electronic engine control module MCO. In a nonlimiting embodiment, this PHJNIT initialization phase lasts 100 ms, namely the time of the period To2 described below.

In a nonlimiting embodiment, during this PHJNIT initialization phase, information INF from the control module D is awaited in response to each REQ request sent. In a nonlimiting embodiment, the duration between the transmission of the REQ request and said response is limited to the primary duration Toi described below.

In a nonlimiting embodiment, if the microcontroller MC has not received information INF following its request REQ (there has been a collision Co or no response from the control module D in the time allowed, namely during the primary duration You, or there have been other communication errors Com_Err or of data Dat_Err), the microcontroller MC is also adapted to retransmit the same request REQ to said control module D to have the state STAT of the module piloting D. This makes it possible to recover the STAT state of the piloting module D in the event of a punctual collision.

o Detection of an error

In nonlimiting embodiments, the Com_Err communication errors are:

- a full FIFORx primary buffer which indicates that an additional character received has resulted in overwriting of data;

- a secondary FIFOTx buffer which indicates that an additional character cannot be transmitted without overwriting a previous data item to be transmitted.

In nonlimiting embodiments, the Dat_Err data errors are:

- a missing end bit;

- the single-wire serial link is busy, it is not in the inactive state;

- the contents of the BUFFRx reception butter and that of the FIFORx reception buffer are different when a REQ request is sent by the microcontroller MC: there is a collision Co;

- the content of the FIFORx reception buffer has an unexpected value compared to the REQ request sent (request not supported or the INF information of response from the control module D not corresponding to the REQ request sent);

- the primary duration Toi has expired (described below).

Com_Err communication errors and Dat_Err data errors, except Co collision, are detected using the Reg_STAT state register of the UART universal asynchronous transceiver. To this end, the microcontroller MC is adapted to read this state register Reg_STAT from its peripheral. A bit of the status register Reg_STAT is in fact associated with each possible error (of communication or data).

Detection. Of. collision.

In a nonlimiting embodiment, the microcontroller MC further comprises a PPS configuration device (illustrated in FIG. 1) adapted to configure the inputs-outputs of the microcontroller MC.

The PPS configuration device allows the allocation of resources (such as the universal asynchronous UART transceiver) of the MC microcontroller to its input / output pins PN_E / S. Thus, it allows mapping of the STx transmit output and the ERx receive input of the UART universal asynchronous transceiver with a single PN / I / O input / output pin. The transmission output STx and the reception input ERx are thus linked together as illustrated in FIG. 1.

Connecting the STx transmission output to the ERx reception input makes it possible to receive on said ERx reception input a REQ request sent on said STx transmission output.

In addition, this allows the MC microcontroller to:

- receive an IRQ_Rx reception interruption from the universal asynchronous UART transceiver when a REQ request is sent to the control module D on said STx transmission output; or

- receive an IRQ_Rx interrupt from the universal asynchronous transceiver UART when information INF from the control module D is received on the reception input ERx of said universal asynchronous transceiver UART.

More particularly, it is its processing unit UT which receives this reception interruption IRQ_Rx.

When the MC microcontroller sends a REQ request, if there is no Co collision, the MC microcontroller will also receive the REQ request which it sent. In other words, the REQ request is saved in the BUFFTx transmission buffer and the REQ request will be copied into the FIFORx reception buffer simultaneously with the FIFOTx transmission buffer.

If INF information is sent by the control module D at the same time as a REQ request is sent by the microcontroller MC, there is a collision Co. If there is a collision Co, the INF information sent by the control module D will overwrite the REQ request which must be received by the microcontroller MC, namely the REQ request, the data of which is found in the FIFORx reception buffer memory.

The microcontroller MC is thus adapted to compare said BUFFTx transmission buffer and said FIFORx reception buffer memory to detect whether there is a collision Co on said single-wire serial link L. Thus, when there is no collision Co, the content of said FIFORx reception buffer is the same as the content of said BUFFTx transmission buffer, namely the REQ request sent.

If there is a Co collision, the content of said FIFORx reception buffer is different from the content of said BUFFTx transmission buffer. Thus, in this case, said reception buffer FIFORx contains information INF sent by the control module D to the microcontroller MC, while the transmission buffer BUFFTx contains the request REQ sent.

Note that the microcontroller MC knows when it issues a REQ request. Also, as soon as it receives an IRQ_Rx reception interrupt from the universal asynchronous transceiver UART following a transmission of a REQ request, namely when the transmission output STx receives a REQ request, said microcontroller MC performs said comparison to find out whether there is a collision Co.

Following the comparison, if there is a Co collision, the state register Reg_STAT of the universal asynchronous transceiver UART is updated indicating a collision state Co.

Furthermore, if a collision Co is detected, said microcontroller MC is further adapted to retransmit a REQ request previously sent to said control module D as described above. Thus, if the collision Co is only punctual, the microcontroller MC continues the communication with the control module D by sending it again the request REQ which had been overwritten by information INF sent at the same time by the control module D In a non-limiting variant, the retransmission of a request is carried out only once.

In the event that following the retransmission of the REQ request, there is a collision Co again, the microcontroller MC temporarily stops the communication with the control module D and this until the next period To2 described below.

In a nonlimiting embodiment, a primary counter CPT1 (illustrated in FIG. 1) is incremented when a collision Co is detected. In a nonlimiting example, the primary counter CPT1 is initialized to 0 and is incremented by 1. Its value is therefore 1 when there is a collision Co. When there is a retransmission of a REQ request and it there is no more collision Co, the primary counter CPT1 is reset, here to 0.

In a nonlimiting embodiment, a primary duration Toi is defined between a transmission of a REQ request from said MCR microcontroller to said control module D, waiting for a response from the control module D and reception of information INF received by said MCR microcontroller and sent by said control module D following said REQ request. In other words, the response time of the control module D is limited to send a requested message INFs following a request REQ from said microcontroller MC. In a nonlimiting example, the primary duration Toi is less than 10 ms (milliseconds).

In a nonlimiting embodiment, a secondary counter CPT2 is incremented when:

- a collision Co occurs more than twice in succession on the same REQ request sent by the microcontroller MC to the control module D;

- the control module D does not respond twice in succession to the same REQ request sent by the microcontroller MC.

If after a determined number of verifications (defined by the secondary counter CPT2), the collision Co is no longer temporary or the absence of response from the control module D is no longer temporary, said microcontroller MC is also suitable for executing a specific ACT action (function illustrated in Figure 1 EXEC (ACT)). In a nonlimiting embodiment, the specific action ACT is a reset of the electronic engine control module MCO. The secondary counter CPT2 thus makes it possible to check the recurrence of a collision Co or of an absence of response from the control module D.

Thus, in a nonlimiting embodiment, said microcontroller MC is further adapted to execute a determined action ACT if the secondary counter CPT2 reaches a predetermined value V2. In a nonlimiting example, the predetermined value V2 is equal to 6. Thus, after 6 checks in a row, if the fault still exists, it means that the problem is lasting.

It should be noted that the collision Co or the absence of response can be resolved after some time, for example in a time less than 600 ms. Also, the predetermined value V2 is defined at 6.

o Verification

The verification of the reception of INF information is carried out according to a To2 period. This allows said microcontroller MC to check whether it has received unsolicited information INFu from said control module D.

The verification is carried out by means of the state register Reg_STAT of the universal asynchronous transceiver UART in which is saved the last state STAT sent by the control module D. The microcontroller MC thus reads said state register Reg_STAT for perform this verification.

It thus checks the STAT state of the control module D periodically according to the period To2.

If the STAT state has changed compared to the previous state of the control module D, the latter is updated in the memory location STAT_MEM by the microcontroller MC. To see if the state has changed compared to the previous state, the microcontroller MC compares the state register Fteg_STAT of its universal asynchronous transceiver UART and its memory location STAT_MEM, the latter including the previous state .

The STAT state of the control module D is thus refreshed in the memory location STAT_MEM of said microcontroller MC.

This also allows the microcontroller MC to check whether a state and therefore a fault in the control module D is still present.

It will be noted that the period To2 is greater than the primary duration Toi. In a nonlimiting example, the period To2 is equal to 100 ms. Thus, the STAT state of the control module D changes, it can be refreshed in the memory location STAT_MEM of the microcontroller MC every 100 ms.

In a nonlimiting embodiment, the microcontroller MC is adapted to send during the period To2 a determined number N of REQ requests. In a nonlimiting embodiment, this determined number N is equal to 5. Thus, the maximum duration between a transmission of this number N of REQ requests and a reception of information INF following these REQ requests is less than 50 ms (for a duration You less than 10ms). In the case where the retransmission of a REQ request is made only once, the maximum duration between a transmission of this number N of REQ requests and a collision Co following these REQ requests and a retransmission of all the requests REQ and reception of the associated INF information following the retransmission is less than 100 ms, namely less than the period To2. In other words, the period To2 is greater than the maximum duration of communication between the microcontroller MC and the control module D, collisions Co included. The maximum duration of communication between the microcontroller MC and the control module D is equal to:

- the transmission of a determined number N of REC requests by said microcontroller MC and a collision Co which arrives on each of these N REC requests; and

the retransmission of said determined number N of said requests and the reception by said microcontroller MC of the associated INF information.

It will be noted that during the PHJNIT initialization phase described above, all of the transmissions of the N requests REC and reception of the associated information INF is less than the period To2 of 100 ms.

• P.r.Q. cédé.P.

Thus, the electronic motor control module MCO described above is suitable for implementing a communication method P between said microcontroller MC and said control module D via said single-wire serial link L.

The communication method P is described in detail below and with reference to FIG. 2.

The communication method P includes a PHJNIT initialization phase as described above.

In a nonlimiting embodiment, the following variables are used:

- the primary counter CPT1 and the secondary counter CPT2 are initialized to 0;

- the memory location STAT_MEM of the microcontroller MC is initialized with a nominal state value NOM_STAT of the control module D which corresponds to a nominal state which is a normal operating state without fault of the control module D;

- a variable ST_SYNCHK, which indicates whether the period To2 has started or not, is initialized false (here at 0). The To2 period has not yet started. After the PHJNIT initialization phase, the normal PH_STD operation phase begins. It is described below.

In step 0, the To2 period starts. The 100ms start to run. The ST_SYNCHK variable is thus initialized to true (here at 1).

In a nonlimiting embodiment, the communication method P comprises:

- 1) a verification by said microcontroller MC according to period To2 of a reception of information INF from said control module D (step illustrated in FIG. 2 CHK_UNSOLL_STAT (STAT));

- 2) a transmission of a REQ request by said microcontroller MC to said control module D (step illustrated in FIG. 2 TX (MC, D, REQ))

3) detection by said microcontroller MC of a Com_Err communication error or of a Dat_Err data error (step 1 illustrated in FIG. 2 CHK_ERR (Com_Err; Dat_Err), including a collision Co on the single-wire serial link L, said collision detection Co comprising a comparison of said transmission butter BUFFTx and of said reception buffer FIFORx when said reception input ERx receives a request REQ (substep illustrated 3bi in FIG. 2 DETCT_CO);

- 4) reception of said REQ request by said control module D (step illustrated in FIG. 2 RX (D, MC, REQ));

- 5) if no Com_Err communication or Dat_Err data error is detected, a sending by the control module D of INF information to said microcontroller MC (step illustrated in FIG. 2 TX_STAT (D, MC INF (STAT)) , and a reception by said microcontroller MC of said information INF (step 6 illustrated in FIG. 2 RX_STAT (MC, D, INF (STAT)).

In a nonlimiting embodiment, said communication method P further comprises a retransmission by said microcontroller MC of a REQ request previously sent to said control module D if a collision Co is detected or if the primary duration Toi has expired (steps 4a 'illustrated in Figure 2).

In a nonlimiting embodiment, said communication method P also comprises an execution of an ACT action by said microcontroller MC (step 8 illustrated in FIG. 2 EXEC (ACT)).

The steps are described in detail below, o Step. 1

Before starting a communication with the control module D, the microcontroller MC checks whether it has received unsolicited information INFu from the control module D, namely whether it has received a new state STAT from the control module D without the have asked him and therefore a new fault.

To this end, the microcontroller MC reads the content of its state register Reg_STAT of its universal asynchronous transceiver UART (content where there is a STAT state) and compares it to the content of its memory location STAT_MEM which contains the previous state of the control module D.

If the two contents are different, this means that a new STAT state has been sent by the control module D spontaneously (branch OK). The secondary counter CPT2 is set to 0.

The memory location STAT_MEM of the microcontroller MC is updated with the new state value STAT (step 7 illustrated in FIG. 2 UPD_MEM (MC, STAT_MEM, STAT). We then return to step 1 if this new state value STAT is different from the nominal state NOM_STAT. This means that the control module D has a fault. As long as there is a new fault or the fault is present, we return to step 1 and until the fault disappears, namely when we return to the nominal state value NOM_STAT.

If the two contents are equal, this means that no new STAT state has been sent by the control module D (branch NOK), we go to step 2.

o Step .2

In this step, the microcontroller MC wants to communicate with the control module D, because it sends it a REQ request to ask it for its STAT state. In the normal PH_STD operating phase, the REQ request includes a GET_STAT state command.

The primary duration Toi is triggered. The 10ms start to run.

We go to step 3.

o Step 3

The MC microcontroller detects whether there is a Com_Err communication error or a Dat_Err data error.

To this end, it performs the following sub-steps:

- 3a) The MC microcontroller detects if there is a Com_Err communication error (sub-function illustrated in Figure 2 DETCT_ComErr). To do this, it reads the state register Reg_STAT from its universal asynchronous transceiver UART. In particular, it reads the different bits of its state register Reg_STAT.

- If there is a Com_Err communication error (OK branch), the primary counter CPT1 is incremented. We then test whether the secondary counter CPT2 is greater than 6. If so (branch Ok), this means that the ComErr communication error is recurrent. We then go to step 8. Otherwise (NOK branch), we consider that the communication error Com_Err is only punctual and we return to step 1.

- If there is no Com_Err communication error, we go to step 3b) (NOK branch).

- 3b) The MC microcontroller detects if there is a Dat_Err data error (sub-function illustrated in Figure 2 DETCT_DatErr). To do this, except for a Co collision error, it reads the state register Reg_STAT from its universal asynchronous transceiver UART. In particular, it reads the different bits of its state register Reg_STAT.

If there is a Dat_Err data error such as a Co collision, an absence of response from the control module D within 10ms etc. (branch OK), the primary counter CPT1 is incremented. We then test whether the primary counter CPT1 is equal to 2.

- If yes (branch OK), this means that the Dat_Err data error has occurred more than once. In this case, the secondary counter CPT2 is incremented and it is subsequently tested whether the secondary counter CPT2 is greater than 6. If so (branch Ok), this means that the DatErr data error is recurrent. We then go to step 8. Otherwise (NOK branch), we consider that the data error Dat_Err is only punctual and we return to step 1.

- Otherwise (NOK branch), it is estimated that the DatErr data error is only punctual and the microcontroller MC re-issues said REQ request (step 4a ’illustrated in FIG. 2). Following this re-transmission, the status register Reg_STAT is reset to 0 for the detection of data error Dat_Err and the detection of communication error Com_Err.

If there is no Dat_Err data error, we go to step 4) (NOK branch).

It will be noted that the detection of a data error Dat_Err includes a sub-function 3bi) in which a detection of a collision Co on the single-wire serial link L is carried out. To this end, to detect a collision Co, the communication method P further comprises a comparison of the transmission buffer BUFFTx and of said reception buffer FIFORx (described above) when said reception input ERx (described above) receives a request. REQ.

It will be noted that in a nonlimiting embodiment, this step 3 can also be carried out between step 1 and step 2.

o Steps 4, 5 and 6

The control module D receives the REQ request sent by said microcontroller MC (step 4 illustrated in FIG. 2) and if no communication error Com_Err or data Dat_Err is detected, it sends information INF to the microcontroller MC (step 5 illustrated in FIG. 2) within 10 ms of the primary duration Toi;

The microcontroller MC receives them in response to its REQ request (step 6 illustrated in FIG. 2) within 10 ms of the primary duration Toi.

The primary counter CPT1 is reset to 0 as well as the secondary counter CPT2. The memory location STAT_MEM of the microcontroller MC is updated with this new state value STAT (step 7 illustrated in FIG. 2). We return subsequently to step 1 if this new state value STAT is different from the nominal state NOM_STAT.

o Step 8

In this step, a specific action ACT is executed. In a nonlimiting embodiment, a reinitialization of said electronic engine control module MCO is carried out. Concretely, its power is cut and then turned on again.

It will be noted that step 2 can be executed as many times as there are STAT states of the control module D. Thus, in the nonlimiting embodiment where the control module D comprises two states STAT1, STAT2, step 2 can be executed twice: a first state command GET_STAT can thus be sent by the microcontroller MC to the control module D to recover its first state STAT1 and a second state command GET_STAT can thus be sent by the microcontroller MC to the control module D to recover its first state STAT1. Of course, when this step 2 is executed several times, the step 3 which follows the step 2 is executed as many times as the step 2.

It will be noted that as long as the control module D returns a state STAT different from the nominal state NOM_STAT of the control module D, in a nonlimiting embodiment, the steps of the communication method P are repeated. In other words, when there is a fault in the control module D and it occurs repeatedly, the steps of the communication method P are repeated until the fault disappears, namely when we have returned to a normal operating state, the returned STAT state being equal in this case to the nominal value of NOM_STAT state.

Of course, the description of the invention is not limited to the embodiments described above.

Thus, in another nonlimiting embodiment, other two-way communication protocols which do not use an activity monitoring module can be used.

Thus, the invention described has the following advantages in particular:

- it is a simple solution to implement and inexpensive;

- it makes it possible to have a robust communication protocol on a single communication line, because it allows the microcontroller MC to communicate with the control module D to recover a STAT state of said control module D despite the existence of punctual Co collisions or the absence of a specific response from the control module D to a REQ request;

- it makes it possible to detect a fault in the control module D;

- in addition to the faults of the control module D, it also makes it possible to detect a collision Co.

Claims (10)

1. Electronic engine control module (MCO) for a motor vehicle comprising a microcontroller (MC) and a control module (D) adapted to communicate together via a single-wire serial link (L), according to which: - said microcontroller (MC) comprises: - a reception input (ERx); - a transmission output (STx) connected to said reception input (ERx) so that when a request (REQ) is transmitted on said transmission output (STx) by said microcontroller (MC), it is also received on said reception input (ERx); - a reception buffer memory (FIFORx); - a transmission buffer (BUFFTx); - said microcontroller (MC) is suitable for: - send a request (REQ) to said control module (D) and receive information (INF) from said control module (D) via said single-wire serial link (L); - detect a communication error (Com_Err) or a data error (Dat_Err) including a collision (Co) on said single-wire serial link (L), said collision detection (Co) comprising a comparison of said transmission buffer (BUFFTx) and said reception buffer (FIFORx) when said reception input (ERx) receives a request (REQ); - said control module (D) is suitable for: - receive a request (REQ) from said microcontroller (MC) via said single-wire serial link (L); - send information (INF) to said microcontroller (MC) via said single-wire serial link (L). 2. Electronic engine control module (MCO) according to claim 1, according to which said information (INF) is information sent by said control module (D) at the request or not of said microcontroller (MC). 3. Electronic engine control module (MCO)) according to claim 1 or claim 2, according to which a primary duration (Toi) is defined between a transmission of a request (REQ) from said microcontroller (MC) to said control module. (D) and a reception of information (INF) by said microcontroller (MC), information (INF) sent by said control module (D) following said request (REQ). 4. Electronic engine control module (MCO) according to any one of claims 1 to 3, according to which a primary counter (CPT1) is incremented when a collision (Co) is detected. 5. Electronic engine control module (MCO) according to any one of claims 1 to 4, according to which said microcontroller (MC) is further adapted to re-issue a request (REQ) previously sent to said control module (D) if a collision (Co) is detected. 6. Electronic engine control module (MCO) according to claim 4, according to which a secondary counter (CPT2) is incremented if the primary counter (CPT1) is equal to two. 7. Communication method (P) between a microcontroller (MC) and a control module (D) of an electronic engine control module (MCO) via a monofilament serial link (L), according to which said microcontroller (MC) comprises : - a reception input (ERx); - a transmission output (STx) connected to said reception input (ERx) so that when a request (REQ) is transmitted on said transmission output (STx) by said microcontroller (MC), it is also received on said reception input (ERx); - a reception buffer memory (FIFORx); - a transmission buffer (BUFFTx); said communication method (P) comprising: - transmission of a request (REQ) by said microcontroller (MC) to said control module (D) via said single-wire serial link (L); - detection by said microcontroller (MC) of a communication error (Com_Err) or of a data error (Dat_Err), including a collision (Co) on the single-wire serial link (L), said collision detection (Co ) comprising a comparison of said transmission buffer (BUFFTx) and said reception buffer (FIFORx) when said reception input (ERx) receives a request (REQ); - reception of said request (REQ) by said control module (D) via said single-wire serial link (L); - if no communication or data error (Com_Err, Dat_Err) is detected, a sending by said control module (D) of information (INF) to said microcontroller (MC), and a reception by said microcontroller (MC) information (INF) from said control module (D) via said single-wire serial link (L). 8. The communication method (P) according to claim 7, according to which a primary duration (Toi) is defined between a transmission of a request (REQ) from said microcontroller (MC) to said control module (D) and a reception of information (INF) by said microcontroller (MC), information sent by said control module (D) following said request (REQ). 9. Communication method (P) according to claim 7 or claim 8, according to which a primary counter (CPT1) is incremented when a collision (Co) is detected. 10. Communication method (P) according to any one of claims 7 to 9, according to which said communication method (P) further comprises a retransmission by said microcontroller (MC) of a request (REQ) previously transmitted to said module piloting 10 (D) if a collision (Co) is detected. 3064 1/2 MC MCO STAT_MEM, CPT1, CPT2, D OFFMOD, ST SYNCHK UT STAT SAME V S Λ EXEC (ACT) ROM HVAC TX (MC, D, REQ) RX (MC, D, INF (STAT)) CHK_ERR (Com_Err, Dat_Err) / - DETCT_DatErr k_ DETCTCO DETCT ComErr L CHK UNSOLL STAT (STAT) . BUFFTx BUFFRx, Reg_STAT UART P PS STx REQ φ X DC d DC FIFORx FIFOTx ERx ^L PN I / O ^J φ INF (STAT): INFs; INFu X — L STAT = STAT1, STAT2 TX (D, MC, INF (STAT)) RX (D, MC, REQ) Fiq. 1 3064 2/2