Re: layout of 89v51 kit
Each of the three 82C55s has four registers:
A ==> Port A
B ==> Port B
C ==> PortC
Control ==> Control Word
You will be using DPTR and MOVX instructions to address these registers ..
Here are valid addresses:
U14 - load DPTR with:
A ==> DPTR=0000h
B ==> DPTR=0001h
C ==> DPTR=0002h
Control==> DPTR=0003h
U15 - load DPTR with:
A ==> DPTR=0100h
B ==> DPTR=0101h
C ==> DPTR=0102h
Control==> DPTR=0103h
U16 - load DPTR with:
A ==> DPTR=0200h
B ==> DPTR=0201h
C ==> DPTR=0202h
Control==> DPTR=0203h
Which pins do you call: don't care?
Regards,
IanP