USART INTERRUPT STRING READ ISSUE

[Don david]

Posted on March 06, 2017 at 14:21

Hi All,

I am working on STM32f103 CB and i am trying to read the RFID tag EM18 using USART1.Whenever the card is waved  on the Reader, i will receive a interrupt on USART receive pin PA10. Can anybody tell how to copy the received tag in the uart interrupt handler. I am able to copy only the first byte. i want to copy the entire 12 byte in the UART receive interrupt handler .

Below is my code snippet to read the RFID TAG

void USART1_IRQHandler(void)

{     u8 i;    char *t;    RxBuffer[12] ='/0';        {  if(USART_GetITStatus(USART1, USART_IT_RXNE) != RESET)                     /* Read one byte from the receive data register */        for(i=0;i<12;i++)

        {    

      *t  = (USART_ReceiveData(USART1) & 0xFF);              RxBuffer[i] =*t++;            }            //        USART1_TX_Byte(RxBuffer[WriteDataCounter]);        //Uart3Timeout = 10000;                        }        USART_ClearITPendingBit(USART1, USART_IT_RXNE);    } 

Can anybody tell how to implement this

Kind Regards

Don

#usart-string-receive-interrupt #stm32f103cb-usart

[Tesla DeLorean]

Posted on March 06, 2017 at 15:15

The bytes arrive one at a time, copy each into a buffer, and advance the pointer. Don't sit in the IRQ Handler blocking execution.

[S.Ma]

Posted on March 06, 2017 at 15:21

Rename ' i ' into RX_Index; and make it a global variable (declared before the function, and as extern in the H file)

set RX_Index = 0;

Activate the RX interrupt

   Insider the interrupt, store in buffer indexed with RX_Index

   Then RX_Index++

   Then if RX_Index == 12 , disable the USART RX interrupts

In the main loop, wait for RX_Index ==12 to read the buffer.

Rinse and repeat for the next batch.

[tonyblake9]

Posted on May 26, 2017 at 16:20

Hey guys,

I figured I'd jump in here as I have a related problem. I'm using USART3 on an STM32F1 with a serial terminal (RealTerm) and for some reason when I send data from the terminal my USART3_IRQHandler does not fire. I've got the TX side working fine (i.e. I can send data from USART3 to my serial terminal). I've checked my code several times and can't see anything wrong with it:

void USART3_Config(void)

{ GPIO_InitTypeDef GPIO_InitStruct; NVIC_InitTypeDef NVIC_InitStructure; USART_InitTypeDef USART_InitStruct; // 1) Clock Config RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART3,ENABLE); RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB,ENABLE); RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO, ENABLE);

// 2) GPIO Config

GPIO_InitStruct.GPIO_Pin = GPIO_Pin_10; // USART3 TX GPIO_InitStruct.GPIO_Mode = GPIO_Mode_AF_PP; GPIO_InitStruct.GPIO_Speed = GPIO_Speed_50MHz; GPIO_Init(GPIOB, &GPIO_InitStruct); GPIO_InitStruct.GPIO_Pin = GPIO_Pin_11; // USART3 RX GPIO_InitStruct.GPIO_Mode = GPIO_Mode_IN_FLOATING; GPIO_Init(GPIOB, &GPIO_InitStruct);

// 3) NVIC Config

NVIC_InitStructure.NVIC_IRQChannel = USART3_IRQChannel; NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=0; NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0; NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; NVIC_Init(&NVIC_InitStructure); // 4) USART Struct Config USART_InitStruct.USART_BaudRate = 9600; USART_InitStruct.USART_StopBits = USART_StopBits_1; USART_InitStruct.USART_WordLength = USART_WordLength_8b; USART_InitStruct.USART_Parity = USART_Parity_No; USART_InitStruct.USART_HardwareFlowControl = USART_HardwareFlowControl_None; USART_InitStruct.USART_Mode = USART_Mode_Rx | USART_Mode_Tx; USART_Init(USART3, &USART_InitStruct); // Enable RX interrupt USART_ITConfig(USART3, USART_IT_RXNE, ENABLE); USART_Cmd(USART3, ENABLE); }

...

void USART3_IRQHandler(void)

{ if(USART_GetITStatus(USART3, USART_IT_RXNE) != RESET){ // Read one byte from data register RxBuffer[RxCounter++] = USART_ReceiveData(USART3); if(RxCounter == 15){ // Disable interrupt USART_ITConfig(USART3, USART_IT_RXNE, DISABLE); } }}

Can anyone help me with this? Have I missed something?

Cheers,

Tony

[Tesla DeLorean]

Posted on May 26, 2017 at 17:45

Does receive work in polling mode?

Try toggling a GPIO pin.

[Tesla DeLorean]

Posted on May 26, 2017 at 20:37

Review vector table content, and linkage via .MAP file

[tonyblake9]

Posted on May 29, 2017 at 18:21

Hi Clive,

I've tried polling for the data but still no joy. I also tried toggling the GPIO pin that I am using for USART3_RX (PB11) but it doesn't seem to have any effect.

I can see that USART3_IRQHandler is defined in both my vector table and my .MAP file...