STM32F0308 USART set up

Tom Power · ‎2017-08-23

Posted on August 23, 2017 at 17:47

Hi,

I am having trouble getting some basic USART up and running on the STM32F0308-DISCO board. I have tried both sending and receiving and don't seem to see anything coming through on either end. My code is as follows:

Thanks in advance.

#include 'stm32f0xx.h'

#include 'string.h'

#define BSRR_VAL 0x0300

void usart_init( void );

/*-----------------------------------------------------------------------------*/

void usart_init( void )

{

USART_InitTypeDef USART_InitStructure;

GPIO_InitTypeDef GPIO_InitStructure;

RCC_AHBPeriphClockCmd( RCC_AHBPeriph_GPIOB, ENABLE );

RCC_APB2PeriphClockCmd( RCC_APB2Periph_USART1, ENABLE );

/* Configure USART2 pins */

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8 | GPIO_Pin_9;

GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;

GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;

GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;

GPIO_Init( GPIOB, &GPIO_InitStructure );

GPIO_PinAFConfig( GPIOB, GPIO_PinSource8, GPIO_AF_1 );

GPIO_PinAFConfig( GPIOB, GPIO_PinSource9, GPIO_AF_1 );

/* Config USART */

USART_InitStructure.USART_BaudRate = 9600;

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( USART1, &USART_InitStructure );

USART_Cmd( USART1, ENABLE );

}

/*-----------------------------------------------------------------------------*/

void output_init( void )

{

RCC_AHBPeriphClockCmd( RCC_AHBPeriph_GPIOC, ENABLE );

GPIO_InitTypeDef GPIO_InitStructure;

GPIO_StructInit( &GPIO_InitStructure );

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8 | GPIO_Pin_9;

GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;

GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_OUT;

GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;

GPIO_Init( GPIOC, &GPIO_InitStructure );

}

/*-----------------------------------------------------------------------------*/

int main(void)

{

output_init();

usart_init();

while (1)

{

//usart_send_str( 'moving to 180' );

//while (USART_GetFlagStatus(USART1, USART_FLAG_TXE) == RESET);

//USART_SendData( USART1, (uint8_t)'X' );

while ( USART_GetFlagStatus( USART1, USART_FLAG_RXNE) == RESET );

char ch = (char)USART_ReceiveData( USART1 );

if ( ch == 'o' )

GPIOC->BSRR = BSRR_VAL;

else if ( ch == 'f' )

GPIOC->BRR = BSRR_VAL;

}

#stm32f0 #usart

Note: this post was migrated and contained many threaded conversations, some content may be missing.

Tesla DeLorean · ‎2017-08-23

Posted on August 23, 2017 at 19:44

PB8 and PB9 are USART pins?

http://www.st.com/content/ccc/resource/technical/document/datasheet/a4/5d/0b/0e/87/c4/4d/71/DM00088500.pdf/files/DM00088500.pdf/jcr:content/translations/en.DM00088500.pdf

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Tom Power · ‎2017-08-23

Posted on August 23, 2017 at 19:48

I had been playing around with several pins, those must have been the most recent I tried. I also tried PA2 and PA3 with no success.

waclawek.jan · ‎2017-08-23

Posted on August 23, 2017 at 19:55

Tesla DeLorean · ‎2017-08-23

Posted on August 23, 2017 at 22:15

PA2 and PA3 should at least have some connectivity to a USART peripheral, and a free for use on the board.

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Tom Power · ‎2017-08-24

Posted on August 24, 2017 at 13:09

OK, so since my device is an STM32F030R8 device, I should be using USART2 with PA2 and PA3, is this correct?

I have just tried this and I am still not seeing anything.

waclawek.jan · ‎2017-08-24

Posted on August 24, 2017 at 13:26

According to the table from the DS I posted above, there's no USART connectivity on PA2 and PA3 for STM32F030x8.

JW

Elkin Granados · ‎2017-08-24

Posted on August 24, 2017 at 15:49

Hi to everyone!

Checking the user's manual of the discovery board there shows that the pins that you are using to uart are free, pages 19 and 20:

http://www.st.com/content/ccc/resource/technical/document/user_manual/ad/36/2c/ad/32/6c/43/27/DM00092pdf/files/DM00092pdf/jcr:content/translations/en.DM00092pdf

By the way, the right pins are PA9 and PA10, there you havean issue.

I have a question, how are you testing that the uart is not working? are you plugging the board to the computer through a usb-to-serial converter and checking in a terminal if data is received? I made a test code for a nucleo board F030 using CubeMX and System Workbench, and as the nucleoSTLink chips works also as usb-to-serial brigde, for making the test is fast, here is the post:

https://community.st.com/thread/40685-stm32-cubemx-uart?commentID=156868#comment-156868

As the Discovery STlink chip doesn't works as usb-to-serial bridge you should use one external. I recommend to you to use CubeMX for initialize the peripherals, there you can be ''sure'' about the pins that are available in your board.

Tom Power · ‎2017-08-24

Posted on August 24, 2017 at 14:10

According to the document provided by

Turvey.Clive.002

, there should be ( see below ). Or am I misunderstanding?

I have also tried using USART1 and PA9 and PA10, which should work according to the table below, but I have had no luck.

waclawek.jan · ‎2017-08-24

Posted on August 24, 2017 at 14:40

I apparently have an older version of DS missing the footnote 3...

Then USART2 on PA2/3 should work.

As Clive said, make sure the pins are free on that board. Check them as GPIO Input/Output.

What's written on the chip and what is its ID readout?

JW