I have, however, made some substitutions. Probably the most visible is the choice of EPROM. I have a 27C512 socketed. This is because one can use that as a replacement for the 27C256 provided he places the code in the top half of memory. Second item of note would be the connector that has been added to make a detachable battery pack. I thought it would be a nice addition. Third, I didn’t have the proper resistor arrays, so I used one that was close, and the other I substituted with upright resistors. There is nothing more retro than that… And the last substitute was to make odd sized capacitors work, and replacing the 560nF cap with a 100nF cap. I doubt there will be an issue here. Per my previous conversations with Lee I am under the impression that many times he chooses a part because it’s what he has ‘on hand’, and it works. The alternative was to go with a 560nF Tantalum. It would work, but I didn’t want anything that volitile on my chest (I have seen many Tantalum capacitors go ‘boom’ in my history with older computers).
But, a long story short I only lack those two components and burning the ROM in order to have a working example of Lee’s 6502 computer.
But I have another problem. I’ve looked high and low, but have not found my TTL Serial to USB adapter. But, what I do have sitting on my work bench are a bunch of CH340G RS232 to USB ICs as well as plenty of 12mhz oscillators. Ok, so that’s something. I also have some MAX3232CPE RS232 to TTL ICs. So I have options, and should be able to wire something up. I’ve never tried my hand at making my own USB to TTL adapter. But it could be neat. Especially since I have my own 3D Printer. I could make it look decent.
I’ll post an update as soon as it is finished.