RS485 interfacing with stm32f030

[bharti sharma]

Posted on August 31, 2017 at 14:28

hello all,

my question regarding interfacing rs485 with stm32f030r8t6 microcontroller. 485 to ttl converter is used 5v vcc but stm32 works on 3.3v vcc.so how can i interface stm32 with rs485 cnverter. when i  am sending data from stm32 to rs485 some last byte will lost.actually i am working on rs485 modbus protocol. and don't receive any response in  receive buffer register.so please help me with example code using stm32 controller so that i can work on further.

[Vangelis Fortounas]

Posted on August 31, 2017 at 23:02

Hello!

To interface a 5v with 3v device, there are level shifters   like

https://media.digikey.com/pdf/Data%20Sheets/ST%20Microelectronics%20PDFS/ST2129.pdf

.

Knowing the extra costs and space that  shifter occupies ,  consider if it is better

to place a compatible tranceiver like

http://cds.linear.com/docs/en/datasheet/1480fa.pdf

for example.

Suggestion. To fix first the level shift issue. After, you will have clearer vew about any other possible issue with serial port..

Regards

vf