To determine if running on a 83+ or 83+ SE:

in a,(2)
and 80h

;Output is non-zero flag set if on a SE, otherwise Z for normal 83+.



To set the speed on a SE:


To set 6 MHz:

xor a
out (20h),a


To set 15 MHz:

ld a,1
out (20h),a



To determine the speed on a SE:

in a,(20h)
;A = 0 if 6 MHz, A=1 if 15.