Keep in mind that existing available source for the MCS-52 Basic to run it "auto-bauds" the Serial Port. '51 platforms that execute with less than 12 clk cycles per instruction will not perform this correctly. This has been covered in a prev. thread.

While there is a DS80C320 version somewhere on the net (and thus 4 clocks per instr), to test what was then a brand new DS89C420 i just "hard coded" the timer.

regards,
p