Hi,

my Controller runs with 18.432 MHz and the highest baud rate I need is 115200 baud. So I have to feed the internal UART with 115200 * 16 = 1.8432MHz. T2 is already used, T1 is still available. In addition I have to switch the processor speed from x2 to x4 and back. So I can only use the f/(12*(256-TH1)) formula or it will change the baud rate to. But I need f/10!

So I think of feeding T1 from extern with 1.8432 MHz. T1 runs in mode 2 as counter with TH1=0xFF. So it should generate a overflow on every extern clock.

I never used a 8051 UART with external clock. So I'm a bit unsure whether it can work or not. Any comments are wellcome.

TIA

Gustl