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uart communication stm32f4

lacava
Associate II
Posted on March 13, 2012 at 17:23

'morning every body

I need a little help to write an ''echo program'' (micro send anything to the uart and receives back the same transmission). 

does anybody have any ideas about it?? any help is VEEEEEEERY appreciate!! :)

#stm32-uart-usart #echo
13 REPLIES 13
41003160
Associate II
Posted on November 28, 2013 at 16:37

I copy your code and bulid but  have an error   :.\USART.axf: Error: L6218E: Undefined symbol SYSCFG_EXTILineConfig (referred from stm32f4_discovery.o).

Can you correct for me. Thanks

Posted on November 28, 2013 at 16:52

Check that you have stm32f4xx_syscfg.c or stm32f4xx_exti.c in your project.

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anjali8122
Associate II
Posted on September 30, 2015 at 10:59

hey , i used your code in em-blocks software tool and run it with the Tera term for output. i get alpha sign and small n 'n' in the output. I also tried with different baud rate but not able to get proper output. will u pls give me suggestions. I would like to show you my output. pls find attachement.

________________

Attachments :

output.png : https://st--c.eu10.content.force.com/sfc/dist/version/download/?oid=00Db0000000YtG6&ids=0680X000006HzLa&d=%2Fa%2F0X0000000bNu%2FJurIDiuc0JL5f.adFndLzHzoB6wfBkWeLP8xCfIqoLU&asPdf=false
Posted on September 30, 2015 at 13:35

The project might have been more enlightening, but never mind..

This is on what board using what chip?

Does the HSE_VALUE define match the clock frequency used in your design, and is the setting of the PLL clocks in system_stm32f4xx.c reflective of the board/chip used?

Remember the STM32F4-DISCO board uses an 8 MHz clock source, the examples and template in many of the projects assume the use of an EVAL series board with a 25 MHz clock.

If there is still doubt, have the code output a stream of 'U' characters, and look at the waveform with a scope, and measure the bit timings, and confirm it matches the selected baud rate.

Consider also what you're attaching the serial port too, an RS232 port does not have levels that are compatible directly with the CMOS ones on the STM32, you'd need a MAX3232 type level converter.

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