by EmulatorCoder on Sat Dec 01, 2012 9:27 pm
The 7501/8501 variant of the 6510 was used in Commodore's C16, C116 and Plus/4 home computers, where its I/O port controlled not only the Datasette but also the CBM Bus interface. The 2 MHz-capable 8502 variant was used in the Commodore C128. All these CPUs are opcode compatible (including undocumented opcodes), except the 8502, where some differences concerning the undocumented opcodes have been reported[by whom?].
The Commodore 1551 disk drive used the 6510T, a version of the 6510 with eight I/O lines. The NMI and RDY signals are not available.
I would start by downloading the pinouts for 6510 and 8501 and compare.
name: 8501
function: CPU
package: DIL,40
manufacturer: Mostek
+--()--+
0o IN | 1 40| /RESET
RDY | 2 39| R//W
/IRQ | 3 38| D0
AEC | 4 37| D1
VCC | 5 36| D2
A0 | 6 35| D3
A1 | 7 34| D4
A2 | 8 33| D5
A3 | 9 32| D6
A4 |10 31| D7
A5 |11 30| P0
A6 |12 29| P1
A7 |13 28| P2
A8 |14 27| P3
A9 |15 26| P4
A10 |16 25| P6
A11 |17 24| P7
A12 |18 23| GATE IN
A13 |19 22| A15
GND |20 21| A14
+------+