usart3 remapping

kdeganck9 · ‎2009-10-22

Posted on October 22, 2009 at 10:28

usart3 remapping

kdeganck9 · ‎2011-05-17

Posted on May 17, 2011 at 13:26

I do not succeed in 'half' remapping the USART3 on a STM32F103RB device (64LQFP, 128K Flash/20K RAM)

The software works when port 3 in not remapped (with I2C2 clock disabled) and uses the same code as for port 1 and 2.

The pins PC10 and PC11 can be toggled when used as push pull output.

Has anyone experienced a similar problem or can just advice me in what to do next ?

Thanks in advance.

The code below shows the only difference between remap or not by means of the definition of 'USART3_PartialRemap'.

#ifdef USART3_PartialRemap

/* Configure USART3 Rx (PC.11) as input floating */

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_11;

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;

GPIO_Init(GPIOC, &GPIO_InitStructure);

/* Configure USART3 Tx (PC.10) as alternate function push-pull */

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;

GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;

GPIO_Init(GPIOC, &GPIO_InitStructure);

GPIO_PinRemapConfig( GPIO_PartialRemap_USART3, ENABLE );

#else

/* Configure USART3 Rx (PB.11) as input floating */

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_11;

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;

GPIO_Init(GPIOB, &GPIO_InitStructure);

/* Configure USART2 Tx (PB.10) as alternate function push-pull */

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;

GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;

GPIO_Init(GPIOB, &GPIO_InitStructure);

#endif

RCC_APB1PeriphClockCmd( RCC_APB1Periph_USART3, ENABLE);

clive2 · ‎2011-05-17

Posted on May 17, 2011 at 13:26

I'm using USART3 in partial remap mode, also using flow control on a STM32F103RET6 (64LQFP, 512K/64K). Initialization code is similar to yours, I have the remap statement before the GPIO init. I have a GSM modem attached, works fine.

Would look at GPIO-C clock. For the flow control to work you have to park the CAN controller off the RTS/CTS pins, otherwise it interferes with the operation (see errata)

Finally after configuring the pins, enable the clock, then the USART

..

else if (Uart->Port == USART3)

{

/* Enable USART3 Clock */

RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART3, ENABLE);

}

USART_Cmd(Uart->Port, ENABLE); /* Enable the USART */

..

What is the failure mode? Do you not see data on the Tx pin? Is the USART taking data and do you see the registers/status reflect changing internal state?

-Clive

kdeganck9 · ‎2011-05-17

Posted on May 17, 2011 at 13:26

Dear Clive,

Thanks for your response.

I tried on a 'RET6' device too and I have the same problem.

The GPIO clocks are enabled, otherwise I would be able to toggle the pins via JTAG.

I also tried the remap statement before and after.

But in the next coming days I'll try some other things you propose.

regards,

Koen

domen2 · ‎2011-05-17

Posted on May 17, 2011 at 13:26

AFIO clock?

kdeganck9 · ‎2011-05-17

Posted on May 17, 2011 at 13:26

Domen,

Thank you very much.

Now it works.