Having spend all day changing USB ports and cables around to get my new TL866-II+ programmer to work. I prayed and demon from hell pointed out what to plug in and when and handed me CD with software. Thier cable and the BACK usb port and the latest download.
Then it passed the self test.
That a side, do we still find small parts like a 4K EPROM and how do
we program them? New programmers can’t support the +20 volfts. When will New OLd Stock run out? Even 28C16’s as replacement
are hard to find other than China.
Ben,
It is more like the case Build a replica XYZ Z80 computer,
that uses a 2Kx8 eprom. I guess a short term fix is a 28 pin
to 24 adaptor of PCB some kind. My junk box has ample parts
at the moment.
Ben.
Yes, I’m quite fond of the AT28xxx EEPROMs, since you can program them with only +5 V, meaning that with appropriate tweaking of hardware (routing the “write” signal) and software (correct delays after writing, and making sure you’re not running code from the device you’re trying to write!) you can even program them in-system.
Do remember that the 28-pin 28xxx parts have a couple of pin assignments different from JEDEC (27xxx) parts: pin 1 is READY/B̅U̅S̅Y̅ or A14instead of Vpp, and pin 27 is W̅E̅ (write enable) instead of A14. I have more details and links to datasheets in my personal notes.