WO2012106973A1

WO2012106973A1 - Uart-based wake-up from sleep method and device

Info

Publication number: WO2012106973A1
Application number: PCT/CN2011/084682
Authority: WO
Inventors: 周兴伟
Original assignee: 中兴通讯股份有限公司
Priority date: 2011-02-10
Filing date: 2011-12-26
Publication date: 2012-08-16
Also published as: CN102096649A; CN102096649B

Abstract

Disclosed is a universal asynchronous receiver/transmitter (UART)-based wake up from sleep method. The method comprises: when no data is to be transmitted, a first device notifying via a tx signal line of the UART of self a second device in communication with the first device; when the second device receives the notification and the second device has no data to be transmitted to the first device, notifying the first device via the tx signal line of the UART of self, and putting the UART of self into sleep state; when the first device receives the notification, putting the UART of self into sleep state; the first device and the second device regularly inspect the output state of rx signal lines of selves, when the output state of the rx signal lines of selves is determined to be having data to be received, waking up the UART of selves. Also disclosed is a UART-based wake up from sleep device. Employment of the method and the device allows for reduced power consumption on the device and reduced use of GPIO resource of the device.

Description

Technical field

The present invention relates to the field of wireless communications, and more particularly to a universal asynchronous receiving/transmitting device

(UART, Universal Asynchronous Receiver/Transmitter) sleep wake-up method and device. Background technique

The serial port is also called serial communication interface. The serial port has the advantage of using a simple communication signal line to realize a strong transmission function and a wide transmission speed range, and has become the most widely used communication interface in recent years. Among them, due to the more types, the serial port has a wide transmission speed; the serial port types include: UART, Serial Peripheral Interface (SPI), and Universal Serial Bus (USB). Among them, the UART has the advantages of low power consumption, simple communication control, no need for driving, and the ability to close the data port when there is no data transmission. Therefore, in practical applications, many devices use the UART as the main interface of communication.

Currently, when using UART for communication between devices, the connection between the four wires (tx, rx, cts, and rts) and the two wires (rx and tx) is mainly used. Among them, in the four-wire connection mode, cts and rts can be used to control the data flow. This connection mode can also be called a flow control connection mode. The flow control connection mode can be used when the transmission rates of the communication parties are inconsistent. , to ensure that no data will be lost. In practical applications, if the UART is not used as a modem port, there is no need to use a four-wire connection. A two-wire connection is sufficient. This is because: Most of the current applications only use the UART as a simple communication port, such as: simple interaction of AT commands, not dial-up as a modem; in addition, with devices such as: application processors ( AP, Application Processor ) The addition of peripheral devices, the general purpose input and output of the chip (GPIO, General Purpose Input Resources such as Output will become more and more tense, because the two lines used as flow control can be reused as GPIO. If the two-wire connection method is used, two GPIO resources can be saved, thus making the AP more flexible and more controllable. For simplicity, it not only improves efficiency, but also reduces resource usage.

Currently, when the AP communicates with its connected devices using the UART, there are several sleep waking methods:

(1) The UART is always on. The UART sleeps only when the AP has no task execution and sleeps. When the AP has a task, it wakes up the UART again. Because the UART is not required when the AP performs the task, the UART is awakened. The state, in this way, will increase the power consumption of the AP, which is not conducive to the design of the AP.

(2) The UART wake-up is implemented by a customized sleep indication and wake-up signal. Since the customized sleep indication and wake-up signal need to occupy the AP's GPIO resources, the AP resource occupancy rate is increased.

(3) The two lines used as flow control are multiplexed into GPIO, and the two-way wake-up is realized by the action of flow control. This method is only applicable to the four-wire connection mode, and the method also increases the occupancy rate of the AP's GPIO resources. Summary of the invention

In view of this, the main object of the present invention is to provide a UART-based sleep wake-up method and apparatus, which can reduce the power consumption of the device and reduce the use of GPIO resources.

In order to achieve the above object, the technical solution of the present invention is achieved as follows:

The present invention provides a UART-based sleep wake-up method, the method comprising: when no data is transmitted, the first device notifies the second device that communicates with the first device by using a tx signal line of the UART;

After receiving the notification, and the second device does not send data to the first device, the second device notifies the first device by using a tx signal line of the UART, and causes the UART of the UART to enter a sleep state; After receiving the notification, the first device enters its own UART into a sleep state; the first device and the second device periodically detect an output state of the rx signal line thereof, and determine that the output state of the rx signal line is data. When receiving, wake up its own UART.

In the above solution, the first device notifies the second device that communicates with the first device by using the tx signal line of the UART of the UART, that is:

The first device sets its own tx signal line to a break mode.

In the above solution, the first device is notified by the tx signal line of the own UART, wherein: the second device sets its own tx signal line to a break mode.

In the above solution, the timing detects the output state of the rx signal line, and determines that the output state of the rx signal line is a data reception, and wakes up its own UART, which is:

Set the function of timing detection of the pin state of its own rx signal line, and increase the UART recovery function in the wake-up processing of the timing detection function, detect the output state of the rx signal line of the device itself through the timing detection function, and determine the rx signal line of the device itself. When the level value is high, the device's own UART is woken up by the UART recovery function.

Set the rx interrupt and add the UART recovery function to the interrupt processing. When the device's own rx signal line level is not low, the rx interrupt is triggered and the device's own UART is woken up by the UART recovery function.

Set the GPIO interrupt and add the UART recovery function to the interrupt processing. When the device detects that the edge or level value is high, it triggers the GPIO interrupt and wakes up the device's own UART through the UART recovery function.

In the above solution, the determining the output state of the rx signal line is when there is data reception. The machine is:

The data sender sends the pre-agreed characters; or,

The data sender sends a pulse signal, and then sends a pre-agreed word payment to the data receiver after the delay.

In the above solution, after awakening its own UART, the method further includes:

Returns a character that has been woken up to the data sender.

The present invention also provides a UART-based sleep wake-up device, the device comprising: a first device and a second device;

a first device, configured to notify the second device by using a tx signal line of the UART when no data is sent; and, after receiving the notification of the second device, bringing the UART into a sleep state; and periodically detecting the rx signal line thereof The output state, determine the output state of its own rx signal line to wake up its own UART when there is data reception;

The second device, after receiving the notification sent by the first device, and having no data to send to the first device, notifying the first device by using the tx signal line of the UART, and bringing the UART into a sleep state; And detect the output state of its own rx signal line, and determine the output state of its own rx signal line to wake up its own UART when there is data reception.

In the above solution, the first device is further configured to wake up its own UART when data is sent to the second device after sleep, and send the pre-agreed character to the second device through its own tx signal line, and receive the first The character returned by the second device indicating the wake-up character;

The second device is further configured to: after receiving the character sent by the first device, return a character indicating that the wake-up is returned to the first device by using the tx signal line of the first device; or

The second device is further configured to wake up its own UART when data is sent to the first device after sleep, and send the pre-agreed character to the first device through its own tx signal line, and receive the returned by the first device. Represents a character that has been woken up;

The first device is further configured to: after receiving the character sent by the second device, by using its own tx letter The line returns a character indicating that the wake up has been returned to the second device.

The UART-based sleep wake-up method and apparatus provided by the present invention, when no data is transmitted, the first device notifies the second device that communicates with the first device through the tx signal line of the UART; the second device receives After the notification and no data is sent to the first device by itself, the first device is notified by the tx signal line of the UART, and the UART of the user is put into a sleep state; after receiving the notification, the first device makes itself The UART enters a sleep state; the first device and the second device periodically detect an output state of the rx signal line thereof, and determine that the output state of the rx signal line of the self is the data UART, and wake up its own UART, so that the UART can be lowered. The power consumption of the device and also reduces the use of device GPIO resources. DRAWINGS

1 is a schematic flow chart of a method for waking up sleep based on UART according to the present invention;

1 is a schematic diagram of a connection mode between devices based on UART communication according to the present invention; FIG. 3 is a schematic structural diagram of a device for sleep wake-up based on UART according to the present invention. detailed description

The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

The UART-based sleep wake-up method, as shown in FIG. 1, includes the following steps: Step 101: When no data is transmitted, the first device notifies the second communication with the first device by using a tx signal line of the UART of the UART. Equipment

Here, FIG. 1 is a schematic diagram of a connection manner between a first device and a second device according to the present invention. As can be seen from FIG. 2, the first device and the second device are connected by two lines. Communicating, that is, the tx signal line of the first device is an rx signal line of the second device, and the rx signal line of the first device is a tx signal line of the second device, where the tx signal line For transmitting data, the rx signal line is used for receiving data; in addition, in order to ensure the stability of the transmission signal, a GND signal line may be added between the first device and the second device, Grounding

Since the present invention adopts a two-wire connection manner, no GPIO can be assisted. Therefore, when the first device has no data transmission, it must be notified to the second device through the tx signal line;

According to the RS232 protocol: In the process of data transmission, in order to enable the transmitted data blocks to be spaced apart, the tx signal line can be set to the break mode during the transmission, that is, the level of the tx signal line is zero; The specific implementation of this step can be:

When there is no data transmission, the first device sets its own tx signal line to the break mode. The specific processing flow set to the break mode is exactly the same as the specific processing flow of the prior art, and is not described here; After the break mode, the level value of the tx signal line of the first device is zero, thereby notifying the second device that no data is transmitted;

The first device and the second device may be any device that communicates according to the UART according to the RS232 protocol, and the first device may be an AP, or a personal computer (PC, etc.), correspondingly, The second device may be a device that communicates with an AP, a PC, or the like using a UART.

Step 102: After receiving the notification and the data is not sent to the first device by itself, the second device notifies the first device by using a tx signal line of its own UART, and brings its own UART into a sleep state;

Here, after the tx signal line of the first device is set to the break mode, the second device detects that the level value of the tx signal line of the first device continues to be zero, and the second device may Therefore, it is determined that the first device has no data to be sent; therefore, the specific implementation of the notification received by the second device may be:

After the second device detects that the level of the tx signal line of the first device is zero for a predetermined period of time, the UART of the first device may be considered to have a condition of entering a sleep state;

Wherein, in actual application, the second device detects the tx signal of the first device After the level value of the line is zero, a timer may be started. After the timer expires, if the level value of the tX signal line of the first device continues to be zero for the duration of the timer, the first The UART of a device has a condition for entering a sleep state; the duration of the timer can be set as needed, for example: 50ms, 100ms, etc.;

The first device is notified by the tx signal line of the UART, specifically: the second device sets its own tx signal line to a break mode; wherein the specific processing flow set to the break mode is related to the prior art. The specific processing flow is the same, and is not described here. If the second device receives the notification and has data to the first device, it does not send any information to the first device.

The specific processing procedure of the second device to bring its own UART into a sleep state is exactly the same as that of the prior art, and details are not described herein again.

Step 103: After receiving the notification, the first device enters its own UART into a sleep state. Correspondingly, the first device detects that the level of the tx signal line of the second device is zero. After the duration, the UART of the second device can be considered to have a condition of entering a sleep state;

In the actual application, after detecting that the level value of the tx signal line of the second device is zero, the first device may start a timer, after the timer expires, if the second device The level value of the tx signal line continues to be zero for the duration of the timer, and the UART of the second device is considered to have a condition of entering a sleep state; the duration of the timer can be set as needed, for example: 50 ms, 100ms, etc.;

The specific processing procedure of the first device to bring its own UART into a sleep state is exactly the same as that of the prior art, and details are not described herein again.

Step 104: The first device and the second device periodically detect an output state of the rx signal line, and determine that the output state of the rx signal line is a data reception, and wake up its own UART.

Here, since communication is based on the UART, there is no external hardware terminal that can benefit Therefore, the UART can only be detected and awakened by software; specifically, it can be: set a function to periodically detect the state of its own rx signal line pin, and add a UART recovery function in the wake-up processing of the timing detection function, The timing detection function detects the output state of the rx signal line of the device itself, and wakes up the UART of the device itself through the UART recovery function when determining that the level value of the rx signal line of the device itself is high; wherein, the timing of the timing can be set according to needs Tested by trial and error, the time duration can be any value between 50 and 500ms, such as: 100ms;

In actual application, the device that communicates with the AP generally has its own rx interrupt detection mechanism. Therefore, if the device that communicates has its own rx interrupt, the specific implementation of this step can also be: Set the rx interrupt, and interrupt The UART recovery function is added during processing, as long as the device detects that the level value of its own rx signal line is not low, that is, when the level value is not zero, the rx interrupt is triggered, thereby awakening the device's own UART;

In actual application, if the first device and/or the second device are self-contained with GPIO, the specific implementation of this step may also be:

Setting the GPIO interrupt and adding a UART recovery function to the interrupt processing. When the device detects that the edge or level value is high, the GPIO interrupt is triggered, thereby awakening the device's own UART;

Wherein, if the tx signal line of the data sender is multiplexed into GPIO, at this time, the sender transmits a pulse signal through its own tx signal line, that is, the rx signal line of the receiver, and can be set to trigger by detecting an edge or a level value. GPIO interrupt, if the sender's tx signal line is not multiplexed into GPIO, then the sender sends a character, then the GPIO interrupt is triggered by detecting the edge; the detected edge can be a rising edge or a falling edge; When applied, you can choose to detect any of the rising and falling edges to trigger the GPIO interrupt.

In the actual application process, the first device and the second device may select any one of the foregoing three detection and wake-up methods; Here, the first device and the second device have previously learned which way the other party detects and wakes up the UART; the first device and the second device determine that the output state of the rx signal line is data receiving. The timing is as follows: The other device has data transmission. At this time, the other device wakes up its own UART first, and then sends the previously agreed characters first, so that the data receiver can wake up its own UART and wake up before sending the data.

Specifically, if the receiver wakes up its own UART by setting a timing detection function or setting an rx interrupt, the two sides of the communication, that is, the first device and the second device, are agreed to be sent to the other party in advance. The character and the feedback from the other party indicate that the character has been awakened. When there is data transmission, the sender first sends the pre-agreed character to the receiver, and then sends the data after receiving the character indicating the wake-up that is returned by the other party; For the AP and the device with which it communicates, when the AP needs to send data to the communicating device, the AP first sends an AT to the communicating device, and the communicating device receives the UART that wakes up itself, and then returns OK to the AP. After receiving the OK, the AP sends data to the communicating device. If the AP does not receive the OK returned by the communicating device within the specified time period, the AP may send an AT to the communicating device again, so that the device receives the communication. When the returned device needs to send data to the AP, the communication device first sends an OK to the AP, and the AP receives the OK. After waking up its own UART, it sends a return AT to the communicating device. After receiving the AT, the communicating device sends data to the AP. If the communicating device does not receive the AT returned by the AP within the specified time, it can send another AP to the AP. OK, so loop, until the AT returned by the AP is received; wherein, the specified duration can be set as needed, for example: 50ms;

When the receiver wakes up its own UART by setting the GPIO interrupt, if the sender's tx signal line is multiplexed into GPIO, then the sender sends a pulse signal first, and the receiver wakes up its own UART after receiving the pulse signal. In order to ensure that the receiver has roused its own UART, it can send the pre-agreed characters to the receiver after a certain interval, for example, 40ms, and then send the data after receiving the character indicating the wake-up returned by the other party; for example, For AP and its The communication device, if the AP wakes up its own UART by setting the GPIO interrupt, and the tx signal line of the device communicating with the AP is multiplexed into GPIO, when the device communicating with the AP needs to send data to the AP, the communication device First, send a pulse signal to the AP. After a delay of 40ms, send an OK to the AP. After receiving the pulse signal, the AP wakes up its own UART, and after receiving the OK, returns the AT to the communicating device, and the communication device receives After the AT, the data is sent to the AP. If the communication device does not receive the AT returned by the AP within the specified time period, it can send an OK to the AP again, and so on, until the AT returned by the AP is received; wherein, the specified duration can be Set according to needs, such as: 50ms;

If the sender's tx signal line is not multiplexed into GPIO, at this time, since the receiver does not detect the level value, the condition for the receiver to trigger the GPIO interrupt is: Edge detection, ie: detection of rising or falling edge, In actual application, it can be set to detect the rising edge or detect the falling edge to trigger the GPIO interrupt. Before sending the data, the receiver sends the pre-agreed character, and then sends the data after receiving the character returned by the other party indicating that the wake-up has been received; For example, for an AP and a device communicating with it, if the AP wakes up its own UART by setting a GPIO interrupt, and the tx signal line of the device communicating with the AP is not multiplexed as GPIO, when communicating with the AP When the device needs to send data to the AP, it first sends an OK to the AP. After receiving the OK, the AP wakes up its own UART and returns the AT to the communicating device. After receiving the AT, the communicating device sends data to the AP, if the device is communicating. If the AT returned by the AP is not received within the specified duration, the AP may be sent an OK again, and the loop is received until the AT returned by the AP is received; The specified duration can be set as required, for example: 50ms;

It should be noted here that: since the connection mode based on the UART communication between the devices of the present invention is a two-wire connection mode, any characters, pulse signals, and data transmitted by the sender are transmitted to the reception through their own tx signal lines. In addition, any characters, pulse signals, and data returned by the receiver in the receiving direction are also returned to the sender through its own tx signal line. In order to achieve the above method, the present invention further provides a UART-based sleep wake-up device. As shown in FIG. 3, the device includes: a first device 31 and a second device 32;

The first device 31 and the second device 32 each include a UART module;

The first device 31 is configured to notify the second device 32 through the tx signal line of the self UART when no data is transmitted; and after the notification of the second device 32 is received, bring the UART into a sleep state; and periodically detect itself. The output state of the rx signal line determines the output state of its own rx signal line to wake up its own UART when there is data reception.

The second device 32 is configured to notify the first device 31 through the tx signal line of the self UART and receive the UART of the first device 31 after receiving the notification sent by the first device 31 and transmitting data to the first device 31. Enter the sleep state; and detect the output state of its own rx signal line, and determine the output state of its own rx signal line to wake up its own UART when there is data reception.

Here, it should be noted that the first device 31 and the second device 32 communicate by using a two-wire connection.

The first device 31 is further configured to wake up its own UART when data is sent to the second device 32 after sleep, and send the pre-agreed characters to the second device 32 through its own tx signal line, and receive The character returned by the second device 32 indicating that the wake up is;

The second device 32 is further configured to: after receiving the character sent by the first device 31, return a character indicating that the wake-up is sent to the first device 31 through the tx signal line of the first device; or

The second device 32 is further configured to wake up its own UART when data is sent to the first device 31 after sleep, and send the pre-agreed characters to the first device 31 through its own tx signal line, and receive the first The character returned by device 31 indicates that the character has been woken up;

The first device 31 is further configured to: after receiving the character sent by the second device 32, return a character indicating that the wake-up has been sent to the second device 32 through the tx signal line of the second device 32.

Here, the specific processing procedure of the first device and the second device in the device of the present invention has been reviewed above, and details are not described herein again. The above description is only for the preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included. Within the scope of protection of the present invention.

Claims

Claim

A sleep wake-up method based on a universal asynchronous receiving/transmitting device (UART), characterized in that the method comprises:

When there is no data transmission, the first device notifies the second device that communicates with the first device through the tx signal line of the UART;

After receiving the notification and the data is not sent by the second device to the first device, the second device notifies the first device by using the tx signal line of the UART, and causes the UART of the UART to enter a sleep state;

After receiving the notification, the first device causes its own UART to enter a sleep state;

The first device and the second device periodically detect the output state of the rx signal line, and determine that the output state of the rx signal line is the UART that wakes up when there is data reception.

2. The method according to claim 1, wherein the first device notifies the second device that communicates with the first device by using a tx signal line of the UART of the UART, that is:

The first device sets its own tx signal line to a break mode.

3. The method according to claim 2, wherein the notifying the first device by using a tx signal line of the UART is:

The second device sets its own tx signal line to a break mode.

The method according to claim 1, 2 or 3, wherein the timing detects an output state of the rx signal line, and determines that the output state of the rx signal line is a data reception, and wakes up its own UART. For:

5. The method according to claim 1, 2 or 3, characterized in that said timing detection The output state of its own rx signal line determines the output state of its own rx signal line to wake up its own UART when there is data reception, which is:

Set the general-purpose input/output (GPIO) interrupt, and add the UART recovery function in the interrupt processing. When the device detects that the edge or level value is high, it triggers the GPIO interrupt and wakes up the device's own UART through the UART recovery function.

The method according to claim 1, 2 or 3, wherein the timing of determining the output state of the self rx signal line as having data reception is:

The data sender sends the pre-agreed characters; or,

8. The method of claim 7, wherein after awakening its own UART, the method further comprises:

Returns a character that has been woken up to the data sender.

A UART-based sleep awake device, the device comprising: a first device and a second device;

a first device, configured to notify the second device by using a tx signal line of the UART when no data is sent; and, after receiving the notification of the second device, bringing the UART into a sleep state; and periodically detecting the rx signal line thereof The output state, determine the output state of its own rx signal line to wake up its own UART when there is data reception; The second device, after receiving the notification sent by the first device, and having no data to send to the first device, notifying the first device by using the tx signal line of the UART, and bringing the UART into a sleep state; And detect the output state of its own rx signal line, and determine the output state of its own rx signal line to wake up its own UART when there is data reception.

10. Apparatus according to claim 9 wherein:

The first device is further configured to wake up its own UART when data is sent to the second device after sleep, and send the pre-agreed character to the second device through its own tx signal line, and receive the returned by the second device. Represents a character that has been woken up;

The first device is further configured to: after receiving the character sent by the second device, return a character indicating that the wake-up is returned to the second device by using the tx signal line of the second device.