Hello,

I am trying to get the maximum baud rate with a T89C51CC01 controller and a 20MHz crystal.

It seems that the best I can do is 28800 bps (3.3% error) with the following settings :

CKCON=1
SMOD1=1
TH1=249

However, with the same crystal, the original UART bootloader works up to 57600 bps (it works, I have tried ...)

What am I missing ?