DE102005005090B3 - Method for switching between parallel-circuited electronic modules, requires storage of configuration value in first programmable register - Google Patents

Abstract

An electronic module has at least one driver circuit for driving an output signal of the electronic module, where the driver circuit can be switched between a high resistance output state at the signal output and a low resistance state at the signal output. A first programmable register stores a configuration value and a first logic circuit logically processes a configuration value stored in the register with an external switch-over control circuit. A second programmable register stores an initializing value and a second logic circuit logically processes the initializing value stored in the second register with the value outputted from the first logic circuit to generate the internal switch-over control signal. An independent claim is included for a method of switching between output signals.

Description

The The invention relates to a method for switching between the output side parallel interconnected electronic components, each one switchable driver circuit for driving the output signal.

The JP 2002-26 713 A describes an input / output circuit with driver circuits for Driving an output signal to a signal output. The output switching register controls over one Decoder the two output buffer circuits.

The DE 102 31 641 A1 describes a semiconductor circuit with controllable driver circuits which are driven in dependence on the data content of a control register.

The US 5,394,034 describes an electronic device with a driver circuit driven by a 1-out-of-N decoder.

The US 5,294,845 describes a data processor having an output terminal with selectable output impedance. In this case, a memory device is implemented by a 1-out-of-N decoder.

The EP 0 793 347 A1 describes a custom integrated circuit having selectable output driver circuits connected in parallel to a cable on the output side and driven by a decoder.

1 shows a device according to the prior art, in which at least two similar electronic components output side are connected in parallel at their respective signal output (Out) and are connected to a common output signal line. The electronic components may be any electronic components, in particular integrated circuits. The electronic components or components mutually drive the common output signal, as in 1 shown. At a certain point in time, only one electronic component is active at a time and drives an output signal to the common output signal line Sig, while the signal outputs of the other components are high-impedance.

The signal outputs The electronic components have in addition to the electrical active State in which the output resistance of the signal output has a low resistance is another condition in which the output resistance at the signal output of the electronic component is high impedance. This Condition is also called tristate condition. In digital electronic components, the respective signal output has two active states on, in which the output resistance at the signal output has a low impedance is, namely a binary logical high state H and a logic low state L. The logical high state corresponds for example to a high output voltage of +3.3 V while the logic low state of an output voltage of, for example 0 V corresponds.

The electronic modules have on the output side to each of their signal outputs one Driver circuit, which is used to drive the respective output signal is provided. It depends on an internal Switchover control signal (tri) of the output driver between a high-impedance Output resistance at the signal output and a low impedance Output resistance at the signal output in response to the internal switching control signal switched.

At the in 1 According to the prior art arrangement, the output signal Sig may be an analog or a digital signal. For example, the common output signal Sig may be a data signal to which the data of a plurality of electronic components are mutually multiplexed (so-called "wired-or" arrangement).

In Other applications may be at the common output signal to be an analog signal, the non-active, i. high resistance switched, electronic components are provided redundant. Is detected during operation that the active device is off any reason fails, one of the hitherto inactive, high impedance switched components are switched active, i. the corresponding Driver circuit is by means of an internal switching control signal in a switched low-impedance state. Typical applications for such Applications are so-called high availability systems, where always it must be ensured that no failure of the output signal while ongoing operation.

The switching between the electronic components is carried out according to the prior art in a conventional manner, as in 2 . 3 is shown.

At the in 2 illustrated arrangement according to the prior art, the switching between the electronic module A and the electronic module B via a software interface, in which a common controller or a common control circuit via programming lines sets a control bit in a respective control register of the electronic component. At the in 2 In the embodiment shown, the control bit of the first block is always negated by the controller and programmed to the control bit of the second block. If the two blocks are programmed by the common controller, the programming is always sequential or sequential.

During the Period starting from the programming of the first block up to the programming of the second module, the two have Control bits in the registers therefore have the same logical value. This may possibly result in e.g. the two electronic components simultaneously are active and therefore the output signal simultaneously float. This can lead to electrical problems all the way to the destruction of the lead electronic components.

An alternative arrangement for switching between electronic components according to the prior art is in 3 shown. In this arrangement, the control of the switching operation is carried out directly by means of a control signal K. In the in 3 illustrated arrangement according to the prior art, an inverter is provided on the common circuit board of the blocks, which outputs the control signal inverted in a control input of the first block. In this way, the first electronic component is controlled directly with the control signal K and the second electronic component with the inverted control signal K. The provision of an external inverter outside of the blocks represents a relatively high circuitry overhead, since the external inverter forms an independent electronic component. Furthermore, the provision of inverters outside of the modules leads to increased space requirements on the board and to additional effort in routing the signal lines within the entire electronic circuitry.

It is therefore the object of the present invention, an electronic Building block that ensures safe switching with both low circuit-technical effort as well as non-time critical ensured.

These The object is achieved by a electronic module with the specified in claim 1 Characteristics solved.

at a preferred embodiment the inventive electronic Block is this at its signal output with more electronic Blocks connected in parallel.

at a preferred embodiment the inventive electronic Block is the first logic gate an EXOR gate.

at a preferred embodiment the inventive electronic Block is the second logic circuit an OR gate.

at a preferred embodiment the inventive electronic Blocks are the two programmable registers via a software interface of the electronic component programmable.

at a preferred embodiment the electronic component according to the invention the electronic component is an integrated circuit.

at a preferred embodiment the electronic component according to the invention the electronic component is a transceiver.

• (a) Initialisieren aller Treiberschaltungen der ausgangsseitig parallel verschalteten Bausteine auf einen hochohmigen Zustand;
• (b) Konfigurieren der initialisierten Bausteine jeweils als aktive oder passive Bausteine über eine Software-Schnittstelle;
• (c) Sensibilisieren bzw. Aktivierung der konfigurierten Bausteine über die Software-Schnittstelle; und
• (d) Umschalten zwischen den sensibilisierten Bausteinen in Abhängigkeit von einem an die elektronischen Bausteine angelegten externen Umschalt-Steuersignal.

The invention further provides a method for switching between output signals of the electronic components according to the invention connected in parallel at the output of a respective signal output, each having a switchable driver circuit for driving the output signal, comprising the following steps:

• (a) initializing all driver circuits of the output side connected in parallel blocks to a high-impedance state;
• (b) configuring the initialized devices as active or passive devices via a software interface;
• (c) sensitizing or activating the configured modules via the software interface; and
• (d) switching between the sensitized devices in response to an external switching control signal applied to the electronic devices.

in the Other preferred embodiments of the electronic component according to the invention and the method according to the invention for Switching between such electronic components with reference on the attached figures In order to explain features essential to the invention described.

It demonstrate:

1 a general arrangement according to the prior art;

2 a prior art arrangement for switching between two electronic components;

3 an alternative embodiment of the prior art for switching between two blocks;

4 an inventive arrangement for switching between electronic components;

5 a preferred embodiment of the inventive arrangement for switching between electronic components;

6 a preferred embodiment of in 5 logic circuitry provided within the devices;

7 a flowchart for explaining the method according to the invention for switching between parallel-connected electronic components;

8th a table for explaining the switching method according to the invention;

9 a preferred embodiment of the inventive arrangement with switchable blocks;

10 a preferred embodiment of the inventive arrangement for switching between transceiver modules.

4 shows an inventive arrangement for switching between a first electronic component 1 and a second electronic component 2 , The two electronic components 1 . 2 each have a signal output Out-1, Out-2, which are connected to a common output signal line 3 are connected. The electronic components 1 . 2 each have a driver circuit D-1, D-2, which are provided for driving the output signal. The driver circuit is switchable in response to an internal switching control signal (tri) between an active low-impedance state and a passive high-impedance state. In a passive, high-impedance state, the signal output Out has a high output resistance value. The respective driver circuit Di in each case drives an internal output signal generated by a data processing unit or signal processing unit. The electronic components further include a programmable register Ai for storing a configuration value RA _i . The number of register bits which can be stored in the configuration register depends on the number of electronic components connected in parallel on the output side. Furthermore, each module contains 1 a first logic operation circuit VA-i which logically associates the configuration value RA _i stored in the configuration register Ai with an external switchover control signal K to generate the respective internal switchover control signal tri-i. For this purpose, the first logic operation circuit VA-i via an input signal terminal IN-i to a common control line 4 connected to the application of the external switching control signal K. The two programmable registers A-1, A-2 of the blocks 1-1, 1-2 are each via a software interface SW-i to a common programming line 5 and a reset line 6 connected.

at the first logical combination circuit VA-1 is preferably an EXOR gate (logical antivalence). In this case, the control signal K by the first logic operation circuit VA-i of the respective electronic module with that in the associated configuration register A-i set logical value for generating the internal switching control signal tri-i logically linked. The logical link VA-i is carried out in a similar manner according to the invention in each of the electronic components 1-i either by a logical equivalence or logical antivalence of the stored control bit with the external one Control signal K.

Becomes the configuration bit RA-1 of the first electronic module 1-1 negates to the control bit RA-2 of the second electronic component 1-2 is programmed, with the common control signal K without Necessity of an external inverter of an electronic component active and the other electronic module inactive or switched high impedance. The link the external control signal K either by a logical equivalence or logical antivalence ensures that the internal switching control signal always logically in one of the two electronic components 1, i.e. the corresponding signal output is switched to high impedance. This will be a possible destruction of the electronic component for the case that both blocks simultaneously low-impedance on the output side are switched prevented.

The Programming the configuration bits, which in the first programmable Register A-i of the block 1-i are stored, takes place once during commissioning of the circuit board in an initialization step. The switching between the electronic components depending on from the external control signal K then takes place in a normal operating mode the circuit board.

Switching between the two electronic components 1-1, 1-2, as shown in 4 are also time-critical, since the switching takes place simultaneously in both blocks. It is therefore possible in the inventive arrangement to perform dynamic switching, ie, for example, "real-time multiplexing" of the common output signal SIG possible. When the common output signal "Sig" forms an output signal of a common bus driven by the electronic components, the bus is multi-master capable, ie, it can switch between the two masters or electronic components without loss of performance.

5 shows a preferred embodiment of the electronic module according to the invention, in which in addition to the first programmable configuration register RA-i, a second programmable register RB-i is provided for storing an initialization value RB _i . Furthermore, the electronic module 1-i according to the invention in the in 5 illustrated preferred embodiment, a second logical combination circuit VB-i in addition to the first logic operation circuit Vi. The second logic operation circuit VB-i of the electronic module 1-i according to the invention is preferably an OR gate which supplies the initialization value RB-i temporarily stored in the second programmable register RB-i with the output signal value of the first logic operation circuit Vi Generation of the internal switching control signal tri-i logically linked.

6 shows a preferred embodiment of each provided in the electronic module 1-i logic circuit Li with an EXOR gate as the first logic operation circuit VA-i and with an OR gate as the second logic operation circuit VB-i.

7 shows a flowchart for explaining the switching operation between two electronic modules 1-1, 1-2 at the in 5 illustrated preferred embodiment of the inventive arrangement.

After a start step SO, the two modules 1-1, 1-2 are first initialized to a high-impedance state, ie, the two internal switching control signals tri-1, tri-2 are each logically high. This is accomplished by setting the initialization value RB-i latched in the second programmable register RB-i to logic high for all devices after the devices 1-i have passed the reset line 6 received a reset command. Owing to the OR circuit VB-i, the internal switching control signal tri-i is then logically high for all the blocks. The value buffered in the first programmable register RA-i of the blocks does not matter at this time.

After the initialization in step S1, the two electronic components 1-1, 1-2 via the respective software interface SW-i, for example, by a common controller by means of the programming lines 5 configured, ie it is configured whether the respective electronic component is active or passive. For example, the first electronic module 1-1 is activated for normal operation by setting the control bit in the programmable configuration register RA-i to a logical high. At the in 7 For example, the first electronic device 1-1 is actively configured, and the second electronic device 1-2 is passively configured by setting a configuration value in the RA-1 register to 0 and setting the configuration value in the RA-2 register to 1 puts. During the configuration step S2, the initialization values stored in the programmable second register RB-i continue to be logically high, so that the two components continue to have a high-resistance output resistance during the configuration.

After this the configuration of electronic components 1-1, 1-2 in step S2 is completed, in step S3 sensitization takes place the configured blocks 1-1, 1-2 via the respective software interface SW-1, SW-2 for a subsequent hardware switch. For this purpose, in step S3 the initialization value buffered in register RB-i reset to 0. The reset the initialization value to 0 is done in all electronic Blocks over the respective software interface.

To the sensitization in step S3 work the sensitized electronic blocks 1-1, 1-2 according to the step S2 set configuration. You are then ready for a subsequent one Hardware switch by means of the control signal K. For example, if the system recognizes in step S2, the actively switched electronic component 1-1 failed, a control circuit generates the external switching control signal K and applies it to both electronic modules 1-1, 1-2. In step S-4 is then a switch from the electronic module 1-1 on the electronic module 1-2.

8th Fig. 14 shows a table of an example of the two-component electronic switching device 1-1, 1-2 of the present invention for explaining the flowchart 7 shown switching. After the initialization step S1 Both electronic modules 1-1, 1-2 are switched to high impedance.

in the Configuration step S2, the block 1-1 is actively configured, and block 1-2 is configured as passive. For example, serves the building block 1-2 as a standby building block, which takes over the functions of the block 1-1 if it fails.

By reset of the initialization value RB-i in both blocks 1-1, 1-2 via the Software interface work the building blocks according to their Configuration and are then both for a subsequent switchover Sensitized in step S3.

The switching takes place in dependence on the external control signal K. If, after the sensitization in step S4, the control signal K is switched from logic 0 to logic 1, the module 1-1 is switched to the high-resistance state (tri-1 = 1), and the Module 1-2 has a low output resistance at its signal output (tri-2 = 0). After the switchover in step S4, thus, the block 1-2 is active, while the block 1-1 is inactive. Subsequently, the table shows in 8th a further switching, in which the external control signal K is switched back to 0. After this second changeover, block 1-1 is again active, and block 1-2 is switched back to the passive, high-resistance state (tri-2 = 1). In this way, in addition to the standby operation and an alternating switching between the blocks 1-1, 1-2 in response to the control signal possible.

9 shows the arrangement according to the invention, in which m electronic modules 1-1 to 1-m output side are connected in parallel. The number m of the blocks connected in parallel forms a power of two. In each of the electronic components 1-i, n control lines K1-Kn are connected in each case in the same way. The control bits latched in the registers are each linked to a logic circuit VA1-1 to VA1-n. The first logic gates VA-1 through VA1-n within the logic circuit L1 of the electronic chip 1-1 are either an antivalence link or an equivalence link.

The logic circuit Li of the respective electronic module 1-1 has in the in 9 In the illustrated embodiment, an additional logical AND gate VC-i logically ANDs the logic outputs of the first logic gates VA1-1 through VA1-n. The logical output of the AND gate is logically ORed by the second logic combiner VB-i of the respective electronic device 1-i with the initialization value RB-i latched in the second programmable register to produce the internal switching control signal tri. Each of the m electronic components 1-i, whose signal output Out-i to the common output signal line 3 is connected, is controlled via n control lines 4-i to switch. In this case, each of the m electronic modules 1-i previously receives an individual programming of its registers. One of the electronic components is active during normal operation and drives the signal line 3 ,

10 shows a concrete embodiment of the circuit arrangement according to the invention for switching between electronic components 1-1, 1-2, wherein the electronic components 1-1, 1-2 are each formed by a transceiver. Specifically, the two transceivers are an OctalFALC transceiver connected in parallel to a single E1 / T1 link. The E1 / T1 connection consists in each case of a two-wire telephone line for the transmit direction (transmit line) and for the receive direction (receive line). In the transceiver modules 1-1, 1-2, a digital data stream is converted into a symbol sequence in the transmission direction and transmitted. At the same time, a received symbol sequence is converted into a digital data stream, which is available in a common output signal line RDO.

The Transmitter of the two transceiver modules 1-1, 1-2 are at the same Signal line connected, with transformers for line adaptation are provided. The exits the receiver of the two transceiver modules 1-1, 1-2 are connected to one common output data signal line RDO connected.

Just one of the two transceiver modules may be added to a given one Time to be active and then drives its analog transmitter outputs XL1, XL2 and its digital receiver output RDO. With each other Transceiver module are the transmitter outputs XL1, XL2 and the receiver output RDO at this time high impedance connected.

Switching between the two transceiver modules 1-1, 1-2, as described in 10 are shown, according to the invention according to the switching operation, as a flowchart in 7 is shown.

The switching between the two transceivers is done according to the inventive method without loss of a single data bit at the RDO signal output or a single data symbol at the transmitter output, since in both the receive and in the transmit direction in the transceivers according to the invention internal data buffer are present to cache the data. Both transceiver modules are synchronized with each other and dynamically switched in response to the external control signal K, when in the currently active transceiver module, a circuit-technical problem occurs.

through the switching method according to the invention Be electronic components that have a common output line by combining with register programming, i. Software control, and by applying a control signal safely switched without any timing issues occur. This succeeds with very little circuitry Effort within the electronic components.

Claims (8)

Electronic module (1-i) comprising: a) at least one driver circuit (Di) for driving an output signal (SIG) at a signal output (OUT-i) of the electronic component (1-i), the driver circuit (Di) being connected between a high-impedance Output resistance at the signal output (OUT-i) and a low-resistance output resistance at the signal output (OUT-i) in response to an internal switching control signal (tri-i) is switchable; b) a first programmable register (RA-i) for storing a configuration value (RA _i ); c) a first logic operation circuit (VA-i) logically associating the configuration value (RA _i ) stored in the first register (RA-i) with an external switchover control signal (K); d) a second programmable register (RB-i) for storing an initialization value (RB _i ); e) and a second logical combination circuit (VB-i), the initialization value (RB i) stored in the second register (RB- _i ) with the value output by the first logic operation circuit (VA-i) to generate the internal switching Control signal (tri-i) logically linked. Electronic component according to Claim 1, characterized the electronic component (1-i) is connected to the signal output (OUT-i) is connected in parallel with other electronic components. Electronic component according to Claim 1, characterized that the first logical combination circuit (VA-i) an EX-OR gate is. Electronic component according to Claim 1, characterized that the second logic gate (VB-i) is an OR gate. Electronic component according to Claim 1, characterized that the two programmable registers (RA-i, RB-i) via a Software interface (SW-i) of electronic module (1-i) are programmable. Electronic component according to Claim 1, characterized that the electronic component (1-i) is an integrated circuit is. Electronic component according to Claim 1, characterized the electronic component (1-i) is a transceiver. Method for switching between output signals of electronic components connected in parallel on the output side at each signal output ( 1 ) according to claim 1, comprising the following steps: a) initializing (S1) all driver circuits (D) of the components connected in parallel on the output side ( 1 ) to a high-impedance state (tristate); b) Configuring (S2) the Initialized Blocks ( 1 ) in each case as active or passive components via a software interface; c) Sensitizing (S3) the configured blocks ( 1 ) via the software interface for subsequent switching; and d) switching (S4) between the sensitized building blocks ( 1 ) in response to an external switching control signal (K) applied to the electronic components.