STM32F407 - USART6 Tx Frame Error

ygt_1108 · ‎2017-10-18

Posted on October 18, 2017 at 10:31

Hi All,

I tried to use USART6 but the data I sended is corrupted, I check the baudRate bur its looks fine(9600 bps), I add the screen shot of oscilloscope I send 0x79(0b0111 1001) but its showed me irrelevant data, also I tired the diffrent baudrate but result was same,

Here is my USART6 initialization code;

GPIO_InitTypeDef GPIO_InitStruct;

USART_InitTypeDef USART_InitStr;

RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART6, ENABLE);

RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOC, ENABLE);

GPIO_PinAFConfig(GPIOC, GPIO_PinSource6, GPIO_AF_USART6);

GPIO_PinAFConfig(GPIOC, GPIO_PinSource7, GPIO_AF_USART6);

GPIO_InitStruct.GPIO_OType = GPIO_OType_PP;

GPIO_InitStruct.GPIO_PuPd = GPIO_PuPd_UP;

GPIO_InitStruct.GPIO_Mode = GPIO_Mode_AF;

GPIO_InitStruct.GPIO_Pin = GPIO_Pin_6 | GPIO_Pin_7;

GPIO_InitStruct.GPIO_Speed = GPIO_Speed_100MHz;

GPIO_Init(GPIOC, &GPIO_InitStruct);

USART_InitStr.USART_BaudRate = 9600;

USART_InitStr.USART_WordLength = USART_WordLength_8b;

USART_InitStr.USART_StopBits = USART_StopBits_1;

USART_InitStr.USART_Parity = USART_Parity_No;

USART_InitStr.USART_HardwareFlowControl = USART_HardwareFlowControl_None;

USART_InitStr.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;

USART_Init(USART6, &USART_InitStr);

USART_Cmd(USART6, ENABLE);

I send with, USART_SendData(USART6, 0x79);

The response I read on terminal 0b1111 1001(Dec: 159)(Hx: F9)

Thanks in advanced.

Yigit

AvaTar · ‎2017-10-18

Posted on October 18, 2017 at 11:01

Do the settings of your terminal really match (number of bits, stop bits, parity) ?

What do you receive on your F407 board when you send characters from the terminal ?

You can loop back your UART (connect TX to RX), and check what you receive.

ygt_1108 · ‎2017-10-18

Posted on October 18, 2017 at 11:15

Hi

meyer.frank

‌, Thank you for your reply,

I already set my terminal to USART6, and when I send data from terminal, this data

corrupted to,

Send 'a'(0x61) -> Response 0xA1

ygt_1108 · ‎2017-10-18

Posted on October 18, 2017 at 11:39

Now I tried send another data to teminal and the result is ;

TX(F407) RX(TeraTerm)

0b0111 1001 ------------------------------------> 0b1111 1001

0b0100 0111

------------------------------------>

0b1000 0111

0b0101 0100

----------------------------------->

0b1001 0100

I guess some bits is missing, it could be stopbit but why is the stopbit missing?

ygt_1108 · ‎2017-10-18

Posted on October 18, 2017 at 11:41

meyer.frank

‌ I use disco board, The connection between board and Pc by the TLL board(FTDI232)

Rx->Tx

Tx->Rx

ygt_1108 · ‎2017-10-18

Posted on October 18, 2017 at 13:01

Here is the configuration of the terminal program and you're absolutely right about first bit, it is the first time I face like problem

ygt_1108 · ‎2017-10-18

Posted on October 18, 2017 at 13:25

Unfortunately it has not work for me, I did get this configuration from SPL examples, I wonder it might be problem with clock ?I checked but I couldnt see anything, I sharing this configuration, if you see anything wrong please tell me, thanks a lot

RCC_DeInit();

RCC_HSEConfig(RCC_HSE_ON);

HSEStartUpStatus = RCC_WaitForHSEStartUp();

if (HSEStartUpStatus == SUCCESS) {

RCC_HCLKConfig(RCC_SYSCLK_Div1);

RCC_PCLK1Config(RCC_HCLK_Div4);

RCC_PCLK2Config(RCC_HCLK_Div2);

FLASH_SetLatency(FLASH_Latency_5);

FLASH_PrefetchBufferCmd(ENABLE);

RCC_PLLConfig(RCC_PLLSource_HSE, 4, 168, 2, 7);

RCC_PLLCmd(ENABLE);

while (RCC_GetFlagStatus(RCC_FLAG_PLLRDY) == RESET)

;

RCC_SYSCLKConfig(RCC_SYSCLKSource_PLLCLK);

while (RCC_GetSYSCLKSource() != 0x08)

;

AvaTar · ‎2017-10-18

Posted on October 18, 2017 at 11:34

How is the connection done ?

Connecting the 3.3V output of the MCU directly to a COM port does not work, the levels do not match.

ygt_1108 · ‎2017-10-18

Posted on October 18, 2017 at 13:58

Ok I found the problem it was so annoying,

it is happen beacuse of 'HSE_VALUE' symbolic constant it was not equal to actual crystal value, how I forgot the fix it, Thank you so much my friend for try to help me, if I come to germany one day, I gonna order beer for you

ygt_1108 · ‎2017-10-18

Posted on October 18, 2017 at 14:06

it was 25000000, but Ä± use 80000000