Hi Babar,

if you have count the number of cycles, you have
the reverse problem:
Make a delay loop for the new crystal with a different
count of cycles.
I have the following macro (using Keil assembler)
as solution for easy changing the crystal.

Peter



mdelay macro value, rx, ry ;cycle, used register(s)
local m____1
if( value < 5 )
rept value
nop
endm
elseif( value < 515 )
mov rx, #low((value-1)/2)
djnz rx, $
if((value and 1) = 0)
nop
endif
else
mov rx, #high(value/2+253)
mov ry, #low(value/2-2)
m____1: djnz ry, m____1
djnz rx, m____1
if(value and 1)
nop
endif
endif
endm