GR64 UART1 problem


In my aplication i used GR47 modul and now i have to use GR64. It should be compatible, but this doesn’t work when I replace GR47 modul for GR64.

I use /40 variant where is Vref used as a input but in GR47 it was output and I use this for 10kOhm pull-ups on TD, RTS and DTR of UART1

schematic example:

GR47 Diode
pin TD *—|>|-------*MCU
[] 10kOhm
* Vref(pin34 ) on GR47

On /40ver is Vref input so i give voltage for pull-ups from external 3.3V regulator, but this doesn’t work also.

What is effect when i give to ipnput Vref pin external 3.0 voltage on GR64 -> it will use for output IO voltage reference? Or has no effect?

I read that on GR64 use 1.8V logic but on GR47 was 2.78V logic -> maybe this is why it doesn’t work - IO voltage level problem?

On GR47 i used 9600Baud for comunication with MCU because it was default baudrate… on GR64 is 9600Baud default Baudrate too or it’s something else?

Thanks for answer.