Hi Kalpana,If it works with

[AJISH ALFRED]

Hi Kalpana,

If it works with 6.5Mhz crystal then ofcourse you can do the same with 4Mhz, 6Mhz crystal and 8 Mhz crystal by appropriately setting the timer registers.

Suggest you to use 4Mhz or 6Mhz crystal since you need long time period (20ms).