CN102521183B - Serial port simulating method for embedded system - Google Patents
Serial port simulating method for embedded system Download PDFInfo
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- CN102521183B CN102521183B CN201110396365.7A CN201110396365A CN102521183B CN 102521183 B CN102521183 B CN 102521183B CN 201110396365 A CN201110396365 A CN 201110396365A CN 102521183 B CN102521183 B CN 102521183B
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- 238000000034 method Methods 0.000 title claims abstract description 14
- 238000005070 sampling Methods 0.000 claims abstract description 6
- 230000005540 biological transmission Effects 0.000 claims description 13
- 238000012795 verification Methods 0.000 claims description 5
- 230000003139 buffering effect Effects 0.000 claims description 4
- GOLXNESZZPUPJE-UHFFFAOYSA-N spiromesifen Chemical compound CC1=CC(C)=CC(C)=C1C(C(O1)=O)=C(OC(=O)CC(C)(C)C)C11CCCC1 GOLXNESZZPUPJE-UHFFFAOYSA-N 0.000 claims description 2
- 238000009825 accumulation Methods 0.000 abstract 1
- 238000001514 detection method Methods 0.000 abstract 1
- 238000004891 communication Methods 0.000 description 2
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Abstract
The invention discloses a kind of serial port simulating method for embedded system.The invention discloses a kind of method of the mode simulative serial port using software for embedded system.This method by MCU General Purpose I/O pins, I/O pin and timer models serial ports can be interrupted, the Timer Controlling sampling interval is utilized when receiving data, detection receives serial ports binary bits data flow, the data of serial ports reception are synthesized according to the data bit, stop position, check bit of setting, the accumulation of error caused by avoiding timer unstable using I/O interrupt causes Data reception errors；The time for sending each data using Timer Controlling when serial ports is sent sends data come simulative serial port.It is contemplated that taking the mode simulative serial port of software in existing system, so as to reduce the cost of hardware expanding serial port chip, and then the profit margin of product is improved, bring higher economic benefit.
Description
Technical field
The present invention relates to a kind of method for embedded system simulative serial port in a manner of using software, utilize MCU's
General Purpose I/O pins and the interruption of I/O pin can be interrupted combine timer interruption simulative serial port in a manner of software and complete data and connect
Receive and send.
Background technology
Used in industrial circle serial ports and its generally, the change due to customer demand often occur in many matured products,
Need to increase some functions, and these functions need to use extra serial ports, but existing matured product is again without extra
Idle serial ports, MCU is changed or the extra serial port extended chip of increase is both uneconomical to solve if taken for this demand
Increase extra R ＆ D design cost again.
The content of the invention
The present invention carries out the reception and transmission of data by using MCU I/O pin and timer interruption simulative serial port,
In the case of being changed without MCU and the extra serial port extended chip of increase, increase serial ports reduce product Innovation Input and hardware into
This.
To achieve these goals, the technical scheme is that by MCU interrupt I/O pin, General Purpose I/O pins and
Timer models serial ports.When simulative serial port receives data, MCU reception pin down trigger starts sample clock generator, described
The baud rate that the fixed time interval of sample clock generator is set according to simulative serial port is calculated, after timer startup between each sampling
Sampled every the state of the reception IO to simulative serial port, obtain a data bit of the data flow of current time serial ports reception
State, stop sampling after the data bit of byte is sampled, pieced together according to the data bit sampled in this cycle
The data of one byte.When simulative serial port sends data, timer period is set according to simulative serial port baud rate, starts timing
Device, the state of data pin is sent in each cycle according to the data bit for the data to be sent setting simulative serial port, when a byte
Data be sent completely after stop timer.
As materialization, the step of simulative serial port receives data, is：
1. the IO for receiving pin of MCU simulative serial ports is set to be interrupted for low level triggering, wherein the reception pin is can
Interrupt I/O pin；
2. timer is calculated according to the baud rate of simulative serial port setting after pin triggering is interrupted when simulative serial port receives
In the cycle, forbid simulative serial port to receive the triggering of pin and interrupt, start timer；
Wherein, step 2. described in timer period=1/ (simulative serial port baud rate * 2)
3. timer triggers the state for receiving pin of reading simulative serial port after interruption first, draw if simulative serial port receives
The state of pin is that high level then represents that simulative serial port receives corrupt data, forbids timer, returns to step 1.；
Represent that simulative serial port reception data start bit is correct if the state of simulative serial port reception pin is low level, weight
New settings timer period, timer is restarted, step is jumped to and 4. continues；
Wherein, step 3. described in the simulative serial port baud rate of timer period=1/
4. timers trigger reads the state of the reception pin of simulative serial port after interrupting, if simulative serial port receives pin
State is that high level then represents that simulative serial port receives the data that a place value is 1；
Represent that simulative serial port receives the number that a place value is 0 if the state of simulative serial port reception pin is low level
According to；
Keep timer period constant, restart timer；
5. repeating the above steps 4., after repeating n times, 6. no parity check bit walk jumps to step, has verification bit walk then to jump
Go to step 7.；
Wherein, the verification of the stop position of the data bit of N=simulative serial ports setting+simulative serial port setting+simulative serial port setting
Position
6. the data step-by-step received, which is pieced together byte deposit, receives buffering area, notice upper level applications have been received by
One byte data；
7. the high-order number of the data bit received and the even-odd check contrast of setting are counted, if the high position counted
Number with setting even-odd check it is consistent, then the data step-by-step received piece together byte deposit receive buffering area, notice
Upper level applications have been received by a byte data；If the even-odd check of the high-order number counted and setting differs
Cause, abandon this data bit received；
8. stopping timer forbidding timer interruption simultaneously, repeat step is 1. to 7. completion duration data receive process.
As materialization, the step of simulative serial port sends data, is：
(1) it is high level to keep sending pin when no data is sent, wherein it is General Purpose I/O pins to send pin；
(2) when user needs to send data, timer period is set, it is low level to put and send pin, starts timer；
Wherein, the simulative serial port baud rate of the timer period described in step (2)=1/
(3) after timer interruption, set according to the lowest orders of data to be sent and send the level of pin sending
Data shift right one；
Wherein, lowest order is that 1 setting sends pin holding high level, and lowest order is 0 and sets transmission pin to keep low
Level
(4) until current byte is sent completely, no parity check sends data and jumps to step (5) repeat step (3), there is odd even
Verification then jumps to step (6)；
(5) it is high level to put and send pin, completes the transmission of current byte, jumps to step (1) and continues next byte
Send；
(6) following timing week is set according to 1 number sent in the even-odd check of setting and step (3)~(4)
The level of transmission pin in phase；
(7) it is high level to put and send IO, completes the transmission of current byte and keeps the timer period that this sets as 2
In the cycle above, jump to the transmission that step (1) continues next byte.
Method provided by the invention can be under conditions of being changed without design while not increasing extra hardware cost
Increase the serial ports quantity of whole product, to meet the needs of user, the method can directly reduce what change hardware plan was brought
The input of R＆D costs, while the increase for increasing extra hardware and then controlling hardware cost can also be reduced.
Brief description of the drawings
Fig. 1 is to illustrate at the starting I/O interrupt triggering moment of the present invention and the timer interruption moment received in data procedures
Figure；
Fig. 2 is the schematic diagram of the triggering moment of the timer interruption of the delivery time of the present invention.
Embodiment
The present invention is further described with reference to the accompanying drawings and detailed description.
During data are received, the low level that utilization can interrupt I/O pin interrupts the beginning for judging to receive data.Open
The timing cycle of timer is calculated after the reception data that begin according to communication baud rate, sets timer interruption.In timer interruption
Judge the data bit received.Enough data are received in timer interruption according to data bit, check bit, the number of stop position
Position.Data bit according to receiving pieces together the data of a byte.As shown in figure 1, when being triggered for present invention starting I/O interrupt
Carve and receive the timer interruption moment in data procedures.
As shown in Fig. 2 it is the schematic diagram by the triggering moment of the timer interruption of delivery time of the present invention.Sending number
During, according to the interrupt cycle for sending the communication baud rate calculating timer that send data.Each timer interruption
When set according to the data bit currently to be sent MCU I/O pin state.Data bit be sent completely after according to the odd even of setting
1 number in verification and the data bit sent determines the state of the I/O pin that needs are set during timer interruption next time.Hair
Keep sending the time that I/O pin is persistently no less than 2 timer periods for high level after having sent a byte.
The foregoing is only a preferred embodiment of the present invention, is not intended to limit the scope of the present invention.
Claims (1)
1. for embedded system serial port simulating method, methods described by MCU interrupt I/O pin, General Purpose I/O pins and
Timer models serial ports, it is characterised in that
When simulative serial port receives data, MCU reception pin down trigger starts sample clock generator, and the sample clock generator is determined
When the interval baud rate that is set according to simulative serial port be calculated, timer start after in each sampling interval to simulative serial port
The state for receiving IO is sampled, and the state of a data bit of the data flow of current time serial ports reception is obtained, when sampling
Stop sampling after the data bit of one byte, the number of a byte is pieced together according to the data bit sampled in this cycle
According to；
When simulative serial port sends data, timer period is set according to simulative serial port baud rate, starts timer, in each cycle
The state of simulative serial port transmission data pin is set according to the data bit for the data to be sent, when the data of a byte are sent completely
After stop timer；
The simulative serial port receives the step of data and is：
1. the IO for receiving pin of MCU simulative serial ports is set to be interrupted for low level triggering, wherein the reception pin is to interrupt
I/O pin；
2. the cycle of timer is calculated according to the baud rate of simulative serial port setting after simulative serial port receives pin triggering interruption,
Forbid simulative serial port to receive the triggering of pin to interrupt, start timer；
Wherein, step 2. described in timer period=1/ (simulative serial port baud rate * 2)
3. timer triggers the state for receiving pin of reading simulative serial port after interruption first, if simulative serial port receives pin
State is that high level then represents that simulative serial port receives corrupt data, forbids timer, returns to step 1.；
Represent that simulative serial port reception data start bit is correct if the state of simulative serial port reception pin is low level, set again
Determine timer period, restart timer, jump to step and 4. continue；
Wherein, step 3. described in the simulative serial port baud rate of timer period=1/
4. timers trigger reads the state of the reception pin of simulative serial port after interrupting, if simulative serial port receives the state of pin
Then represent that simulative serial port receives the data that a place value is 1 for high level；
Represent that simulative serial port receives the data that a place value is 0 if the state of simulative serial port reception pin is low level；
Keep timer period constant, restart timer；
5. repeating the above steps 4., after repeating n times, 6. no parity check bit walk jumps to step, has verification bit walk then to jump to
Step is 7.；
Wherein, the check bit of the stop position of the data bit of N=simulative serial ports setting+simulative serial port setting+simulative serial port setting
6. the data step-by-step received, which is pieced together byte deposit, receives buffering area, notice upper level applications have been received by one
Byte data；
7. the high-order number of the data bit received and the even-odd check contrast of setting are counted, if high-order counted
Number is consistent with the even-odd check of setting, then the data step-by-step received is pieced together byte deposit receives buffering area, notifies upper strata
Application program has been received by a byte data；If the even-odd check of the high-order number counted and setting is inconsistent, lose
Abandon this data bit received；
8. stopping timer forbidding timer interruption simultaneously, repeat step is 1. to 7. completion duration data receive process；
The simulative serial port sends the step of data and is：
(1) it is high level to keep sending pin when no data is sent, wherein it is General Purpose I/O pins to send pin；
(2) when user needs to send data, timer period is set, it is low level to put and send pin, starts timer；
Wherein, the simulative serial port baud rate of the timer period described in step (2)=1/
(3) after timer interruption, the level for sending pin is set the data sent according to the lowest order of data to be sent
Move to right one；
Wherein, lowest order is that 1 setting sends pin holding high level, and lowest order is 0 and sets transmission pin to keep low level
(4) until current byte is sent completely, no parity check sends data and jumps to step (5) repeat step (3), there is even-odd check
Then jump to step (6)；
(5) it is high level to put and send pin, completes the transmission of current byte, jumps to the transmission that step (1) continues next byte；
(6) set according to 1 number sent in the even-odd check of setting and step (3)~(4) in a following timing cycle
Transmission pin level；
(7) it is high level to put and send IO, completes the transmission of current byte and keeps the timer period that this sets as more than 2
Cycle, jump to the transmission that step (1) continues next byte.
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| CN201110396365.7A CN102521183B (en) | 2011-12-02 | 2011-12-02 | Serial port simulating method for embedded system |
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| CN201110396365.7A CN102521183B (en) | 2011-12-02 | 2011-12-02 | Serial port simulating method for embedded system |
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Cited By (1)
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| CN109213673A (en) * | 2017-07-07 | 2019-01-15 | 深圳市有方科技股份有限公司 | A kind of development approach and device based on serial ports simulation software |
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| CN103268248B (en) * | 2012-10-17 | 2015-12-16 | 厦门雅迅网络股份有限公司 | The method of ARM platform LINUX system Imitating multichannel full duplex serial ports |
| CN105468554A (en) * | 2015-11-27 | 2016-04-06 | 宁波三星医疗电气股份有限公司 | Method for realizing polarity-adaptive UART simulation |
| CN106960168B (en) * | 2016-01-11 | 2020-02-04 | 杭州海康威视数字技术股份有限公司 | Card number data acquisition method and device |
| CN107423239B (en) * | 2017-05-05 | 2019-04-30 | 山东大学 | Low-power scm complete data frame method of reseptance under Halt mode |
| CN107357742A (en) * | 2017-07-14 | 2017-11-17 | 上海瀚银信息技术有限公司 | A kind of serial ports analogy method and computer equipment |
| CN108701112B (en) * | 2017-11-29 | 2020-04-28 | 深圳和而泰智能控制股份有限公司 | Method and device for simulating serial port communication based on query mode |
| CN110879791B (en) * | 2019-09-30 | 2021-03-19 | 湖南格兰博智能科技有限责任公司 | Non-blocking two-wire serial port communication simulation method |
| CN112000600A (en) * | 2020-07-29 | 2020-11-27 | 深圳市智微智能软件开发有限公司 | Method, system, device and storage medium for realizing infrared protocol through IO simulation |
| CN112597081A (en) * | 2020-12-22 | 2021-04-02 | 青岛鼎信通讯股份有限公司 | UART software implementation method based on low-voltage Internet of things sensing terminal |
| CN113806259B (en) * | 2021-08-23 | 2024-06-14 | 宁波奥克斯电气股份有限公司 | Method, device and microcontroller for simulating special communication port |
| CN114253879B (en) * | 2021-12-23 | 2024-07-02 | 北京恒源利通电力技术有限公司 | Multi-channel serial port communication method and system based on software simulation |
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