UART4 Rx

[vivek2]

Posted on September 10, 2012 at 04:03

Hello every1,

few days ago i had a problem with uart tx and nw i have solved that problem. so my tx is working fine now. my rx is working too but very slow and gets junk values. below is my code. int main(void) {   /* GPIOC clock enable */     RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);   /* USART4 clock enable */     RCC_APB1PeriphClockCmd(RCC_APB1Periph_UART4, ENABLE);    GPIO_InitTypeDef GPIO_InitStructure;          GPIO_PinAFConfig(GPIOA, GPIO_PinSource0, GPIO_AF_UART4);/* UART4_TX */   GPIO_PinAFConfig(GPIOA, GPIO_PinSource1, GPIO_AF_UART4);/* UART4_RX */   /*-------------------------- GPIO Configuration ----------------------------*/   GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0 | GPIO_Pin_1;   GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;   GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;   GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;   GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;   GPIO_Init(GPIOA, &GPIO_InitStructure);     USART_InitTypeDef USART_InitStructure; //    USART_ClockInitTypeDef USART_ClockInitStruct;   /* USARTx configuration ------------------------------------------------------*/   /* USARTx configured as follow:         - BaudRate = 9600 baud         - Word Length = 8 Bits         - Two Stop Bit         - Odd parity         - Hardware flow control disabled (RTS and CTS signals)         - Receive and transmit enabled   */     USART_InitStructure.USART_BaudRate = 9600;  //115200;   USART_InitStructure.USART_WordLength = USART_WordLength_8b;   USART_InitStructure.USART_StopBits = USART_StopBits_1;   USART_InitStructure.USART_Parity = USART_Parity_No;   USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;   USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;     USART_Init(UART4,&USART_InitStructure);  //uart     USART_Cmd(UART4, ENABLE);   while (1)   {                 if (USART_GetFlagStatus(UART4, USART_FLAG_RXNE) != RESET)      {        uint16_t x = USART_ReceiveData(UART4);          while(USART_GetFlagStatus(UART4, USART_FLAG_TXE) == RESET);          USART_SendData(UART4, x);      } } As u can see im trying to loop back whatever data i receive. Im using STM32F4-Discovery board with STM32F407VGT6 IC. any help wud be much appreciated. Vivek #wait-for-you--clive1-!-!-! #wait-for-you--clive1-!-!-! #wait-for-you--clive1-!-!-!

[vinothraj]

Posted on September 10, 2012 at 06:40

uint8_t bc;

while{while(USART_GetFlagStatus(UART4, USART_FLAG_RXNE) == RESET); bc = (USART_ReceiveData(UART4) & 0x7F); 

while (USART_GetFlagStatus(UART4, USART_FLAG_TXE) == RESET);

              

USART_SendData(UART4, bc);

}

[vivek2]

Posted on September 10, 2012 at 07:50

thnx vinoth!

i found the problem. it was my interface ic. i was then trying to read a text file(40 KB) using hyperterminal. I can read a part of the file perfectly(say 15-20 lines) and some part is not captured(say 40-50 lines) n so on. my code remains the same as above.

[vivek2]

Posted on September 10, 2012 at 07:51

[Tesla DeLorean]

Posted on September 10, 2012 at 15:50

I think, ideally, you want to add some buffering to provide elasticity between the rate the data comes in and the rate it leaves.