Hi all,

I have using MC9S08DZ60 for my application , i want to set 115200 baud rate using the 4MHZ external crystal?

Please can any one help me find the bus clock for setting 115200 BR.

What is the BUSCLK is suitable for setting 115200 BR using 4MHZ external crystal?

Thanks in advance for your help?

The baud rate is determined by baud=bus/(16*br) where br is the baud rate register, and can take values from 1 to 8191.

So, replace baud with your target of 115200, and solve for bus, and you have: bus=1843200*br

Now, you can fill in your expected bus (say, 24MHz), and get the needed BR value => 13.0208

Not an exact value, so your baud rate (with a rounded BR of 13 -- the closest to 13.0208) will be a little off. I believe up to 5% off total on both sides is acceptable for correct operation.