Multi Software Serial (UART) For STM32

The library work fine for virtualize 6 UART full duplex in baud rate 9600. All UART work together parallelly!

Library Dir:

• Softuart.h
• Softuart.c

Handler & baud rate

The function SoftUartHandler(void) must call in interrupt every 0.2*(1/BR) .

if BR=9600 then 0.2*(1/9600)=20.8333333 uS

highly recommended set maximum CPU clock for Run Handler faster as possible!you also available for use lite version by limited options for slow MCUs.

The library don't change any GPIO config! before using must config TX pins as output and RX pins as input , any TX pin must set to 1 as IDLE and any RX pin must be Pullup.

Example Timer Config

for Baud Rate 9600 :

Config	value
Timer Clock	72 MHz
Prescaler (PSC - 16 bits value)	74
Counter Period (AutoReload Register - 16 bits value )	19
auto-reload preload	Enable
Tim global interrupt	Enable

You also can use Timer frequency calculator.

Calling handler

voidHAL_TIM_PeriodElapsedCallback(TIM_HandleTypeDef*htim)
{
if(htim->Instance==TIMX)
{
SoftUartHandler();
}
}

Config Soft UART

Open softuart.h and edit bellow line as you want:

#defineNumber_Of_SoftUarts 6
#defineSoftUartTxBufferSize	32
#defineSoftUartRxBufferSize	64

If Number_Of_SoftUarts=6 that mean you SoftUartNumber is 0,1,2,3,4,5

After config timer for config Soft UART use SoftUartInit:

SoftUartState_ESoftUartInit(uint8_tSoftUartNumber,GPIO_TypeDef*TxPort,uint16_tTxPin,GPIO_TypeDef*RxPort,uint16_tRxPin);

Using Soft UART

Transmit always is Possible but for Receiving data you must enable listening by calling:

SoftUartState_ESoftUartEnableRx(uint8_tSoftUartNumber);

Received data stored in buffer accessible by below functions:

uint8_tSoftUartRxAlavailable(uint8_tSoftUartNumber);
SoftUartState_ESoftUartReadRxBuffer(uint8_tSoftUartNumber,uint8_t*Buffer,uint8_tLen);

Transmit data:

SoftUartState_ESoftUartPuts(uint8_tSoftUartNumber,uint8_t*Str,uint8_tLen);
voidSoftUartWaitUntilTxComplate(uint8_tSoftUartNumber);

Example test:

Transmit

while(1)
{
SoftUartPuts(0,(uint8_t*)"Hello",5);
SoftUartPuts(1,(uint8_t*)"My",2);
SoftUartPuts(2,(uint8_t*)"Name",4);
SoftUartPuts(3,(uint8_t*)"Is",2);
SoftUartPuts(4,(uint8_t*)"Esmaeill",8);
SoftUartPuts(5,(uint8_t*)"Maarfavi",8);
}

Receive

Example 1:

uint8_tgetchar(uint8_tSoftUartNumber)
{
uint8_tch;
while(SoftUartRxAlavailable(SoftUartNumber)==0);
SoftUartReadRxBuffer(SoftUartNumber,&ch,1);
returnch;
}

Example 2:

uint8_tBuffer[SIZE],Len;
while(1)
{
// Read >= 10 Byte Data if Receivedif(Len=SoftUartRxAlavailable(0),Len>=10)
{
// Move Received Data To Another Bufferif(SoftUartReadRxBuffer(0,Buffer,Len)==SoftUart_OK)
{
// Done
}
}
}

Full Example 3:

#include"softuart.h"
...
voidHAL_TIM_PeriodElapsedCallback(TIM_HandleTypeDef*htim)
{
if(htim->Instance==TIMX)
{
SoftUartHandler();
}
}
uint8_tgetchar(uint8_tSoftUartNumber)
{
uint8_tch;
while(SoftUartRxAlavailable(SoftUartNumber)==0);
SoftUartReadRxBuffer(SoftUartNumber,&ch,1);
returnch;
}
intmain(void)
{
uint8_tch;
...
HAL_TIM_Base_Start_IT(&htimX);
SoftUartInit(0,SU_TX_GPIO_Port,SU_TX_Pin,SU_RX_GPIO_Port,SU_RX_Pin);
SoftUartEnableRx(0);
...
while (1)
{
ch=getchar(0);
SoftUartPuts(0,&ch,1);
//SoftUartWaitUntilTxComplate(0);HAL_GPIO_TogglePin(LED_GPIO_Port,LED_Pin);
}
}