MAX485 and STM32 ?

antonius · ‎2013-12-31

Posted on January 01, 2014 at 01:49

Guys,

Can I use MAX485 and STM32F107VCT6?

I can't find VH max on F107 datasheet, is it possible if I interface MAX485 with STM32F107VCT6 USART ? pin PA9 and PA10 connected directly to MAX485

Any clues ?

Thanks

#contact-bounce

Andrew Neil · ‎2014-01-01

Posted on January 01, 2014 at 13:51

''I can't find VH max on F107 datasheet''

http://www.st.com/web/catalog/mmc/FM141/SC1169/SS1031/LN1564/PF221020

Tables 36-37 ?

A complex system that works is invariably found to have evolved from a simple system that worked.
A complex system designed from scratch never works and cannot be patched up to make it work.

antonius · ‎2014-01-01

Posted on January 02, 2014 at 00:10

Found, thank you,

So it's possible if I use 5V supply for MAX485 but the input is from USART1 of STM32F107, do you reckon ?

Any experience on how to use GPIO as input button ?

Tesla DeLorean · ‎2014-01-01

Posted on January 02, 2014 at 00:59

Both PA9/PA10 are FT (Five Volt Tolerant), an output in OD mode can be pulled to a 5V supply.

Button and GPIO inputs are on practically any Dev/Eval board you can find, look at some schematics.

Typically you have a pull-up to 3V connected to one side of the button, which connects to your GPIO pin, and the other side of the button to ground. With the button not press you see a HIGH, when the button makes to ground you see a LOW.

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Andrew Neil · ‎2014-01-01

Posted on January 02, 2014 at 08:19

Don't forget

http://www.lmgtfy.com?q=contact+bounce

...

A complex system that works is invariably found to have evolved from a simple system that worked.
A complex system designed from scratch never works and cannot be patched up to make it work.