Anyone want one of these?
https://github.com/bkw777/Molex_7880x_bus_tap
I'm going to make one for myself and I don't mind making a few more
along the way, considering "Anyone" is probably just Steve since it
would mostly just be useful for debugging REX and REX-like things.
The two parts are connected by an FFC cable and lets you connect a logic
analyzer to the option rom socket while something is in operation in the
socket.
The cable is thin and you can even install the rom door cover and flip
the machine back over and use normally with the rom hanging out to the
side of the machine.
What I want it for is, this doesn't work, but I think it's close, maybe.
https://github.com/bkw777/REX_ATF
REX Classic and REX# are based on the Xilinx XCR3064XL CPLD. That part
was EOL'ed last year.
This Microchip (ATMEL) ATF1504ASL is a very similar chip, and is still
being made and sold new.
Extra bonus, it's a fully native 5v part, so there is no 3V3 regulator
needed and only one VCC rail to route which makes the pcb simpler.
And I managed to reassign some pins so the jtag pins are not used for
general i/o, so programming is a lot simpler. No more aux power
connection, power cmes from the programmer, no more PORT_EN jumper and
pulldown resistor, just connect the jtag and go.
--
bkw
