NotTooBright
New Member
Hello Forum,
In re-designing an old game-system, based upon the Rockwell 'R65c02' CPU to run at a higher clock speed, i have run into a very curious problem : Replacing the CPU with the 'wdc65co2, i could not get output via the I/O interface board. Amongst other standard TTL 74LS chips on the interface board are 2-off 74LS174 present on the data-bus. If i replace these with DM74LS174 chips, the system works fine. But the same chips by ANY other manufacturer and the system will not give an output via these chips !? I have also tried replacing all of the LS with HCT, HC, F etc. etc. But to no avail ! Can anybody explain why this is ? Because i would like to understand this problem and also to use the wdc processor !
In re-designing an old game-system, based upon the Rockwell 'R65c02' CPU to run at a higher clock speed, i have run into a very curious problem : Replacing the CPU with the 'wdc65co2, i could not get output via the I/O interface board. Amongst other standard TTL 74LS chips on the interface board are 2-off 74LS174 present on the data-bus. If i replace these with DM74LS174 chips, the system works fine. But the same chips by ANY other manufacturer and the system will not give an output via these chips !? I have also tried replacing all of the LS with HCT, HC, F etc. etc. But to no avail ! Can anybody explain why this is ? Because i would like to understand this problem and also to use the wdc processor !