Testing USART1 on STM32F429I-DISCO board

[H UQ]

Posted on October 28, 2013 at 15:22

Hi All,

I am working on USART1 device for STM32F429I_DISCO board. [I have already tested my serial device (code) on stm32429i_eval1 board.]

I am using following USART setup/pin mapping

unsigned int temp;

/* Enable GPIOA on AHB1 */

ENABLE_PERIPHERAL_CLOCK(AHB1, GPIOA);

/* Select Alternate Function 7 for USART1 pins */

temp = GPIO_READ(A, AFRH);

temp &= (0xFFFFF0FF & 0xFFFFFF0F);

GPIO_WRITE(A, AFRH, (temp | (0x00000700 | 0x00000070)));

/* Select Alternate function for USART1 pins */

temp = GPIO_READ(A, MODER);

temp &= (0xFFCFFFFF & 0xFFF3FFFF);  

GPIO_WRITE(A, MODER, (temp | (0x00200000|  0x00080000)));   

/* Enable Clock for USART1 */

ENABLE_PERIPHERAL_CLOCK(APB2, USART1);

My Questions are

Can we test USART1 on STM32F429I_DISCO board?

If yes, then above mentioned pin mapping is correct?

If yes, then should we use JP4[TX, RX]  pins for this purpose?

[Tesla DeLorean]

Posted on October 28, 2013 at 15:35

You could attach a USB-to-CMOS Serial type adapter and confirm it that way.

You could connect PA9/PA10 with a wire or micro-jumpers, and prove it looped back.

You could use a MAX3232 or equivalent type device to generate RS232 levels and add a DB9.

For JP4 to work you'd need to do something with SB11/SB15, but that would connect you too the STM32F103 part, which may/may-not provide the serial connectivity you want. I'd suspect NOT.

[H UQ]

Posted on October 30, 2013 at 16:15

Thanks for reply

For this option

>>>> You could connect PA9/PA10 with a wire or micro-jumpers, and prove it looped back.

Is USART support Loop back mode? It is not mentioned in reference manual

For this option

>> You could use a MAX3232 or equivalent type device to generate RS232 levels and add a DB9.

I have tried to use this option but i receive garbage characters (funny characters) on tera term all the time.

My USART driver works fine without any change [RCC, CLOCK; mentioned above] on STM32429I_EVAL1 board but not on DISCO board.

Should I do some thing more regarding GPIO/RCC/CLOCK settings?

Have any one tested USART1 (PA9/PA10) on this board (STM32F429I_DISCO)

Moreover in one of the thread [[DEAD LINK /public/STe2ecommunities/mcu/Lists/STM32Discovery/Flat.aspx?RootFolder=/public/STe2ecommunities/mcu/Lists/STM32Discovery/Help%20me%20USART%20STM32F4&FolderCTID=0x01200200770978C69A1141439FE559EB459D75800084C20D8867EAD444A5987D47BE638E0F&currentviews=210]Help me USART STM32F4], you have mentioned that

>>> You haven't explicitly stated that you're using an STM32F4-Discovery board, but if you are PA9 is not usable for a USART pin due to a huge bulk capacitor being attached to it.

It means PA9 can not be used for USART testing?

[Tesla DeLorean]

Posted on October 30, 2013 at 17:00

I'm talking about a piece of wire externally (looping back), this will not be discussed in the manual. You send a character, you should receive a character. Functionality of pin confirmed, baud rate implicitly the same.

You have a different board, right? So comments about an

http://www.st.com/web/en/catalog/tools/FM116/SC959/SS1532/PF252419

aren't going to impact a completely different design. Check the schematics.

Baud rates look wrong, or junk on terminal. You can measure bit times on a scope. Most likely you have wrong HSE_VALUE and/or PLL settings. The

http://www.st.com/web/catalog/tools/FM116/SC959/SS1532/PF259094?icmp=stm32f4pr_pron_p3436s_sep2013

has an 25 MHz HSE, the

http://www.st.com/web/catalog/tools/FM116/SC959/SS1532/PF259090

has an 8 MHz HSE. Settings for one won't work with the other, timings, and expectations will be different. Computation for USART baud rates are predicated on knowing what the clocks actually are.

[H UQ]

Posted on November 08, 2013 at 15:04

Thanks for fruitful response.

Successfully tested the serial driver by

• using '' USB-to-CMOS Serial type adapter'' with PA9 and PA10 pins
• Updating HSE_VALUE (8MHZ) and PLL settings