Hi I have aprogram that runson p89c51 and p89v51 when I am usunf an exact baudrate divider. I had to change my crystal and I have 3% error. the p89c51 keeps working fine and the p89v51 works in an unexpected way. Does someone experienced such a problem?
The problem is just what I wrote .the p89c51 works in both cases the same. the p89v51 works on the slow speed just like the p89c51 but on the higher speed , the communication sometimes works and sometime not... i can not figure why only part of the communication works... the problem is that the p89v51 does not behave like the p89c51 in the higher speed. it becomes unstable.
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No, X2
the max crystal for X2 is 20MHz
I am using 17.734 its about 35.... after X2 configuration
try T2 clocking and get the 3% error removed. You are running on the edge of acceptable and at that point a capacitor tolerance can make the difference.
Erik
Thanks! with timer 2 it works. (0.49% error)
It means that we should not take for granted that the p89v51 is 1 to 1 substitute for the p89c51...
NO, It means that we should not take for granted that ANY 'identical' chip is 1 to 1 substitute for the p89c51 when running outside margins