Recently I’ve been working on a new shield for my HVEPROM project to program internal ROM UV erasable versions of Intel’s first microcontroller, released in 1976. I built it because I was trying to repair something with one of these in it, and being able to disassemble and modify the code was a key part of that repair. My universal programmer (quite an expensive one) didn’t support these. Others do, but I wasn’t keen to go splashing out again.
Read more about it here.
Why stop there? Having gone to all that trouble, I thought it’d be interesting to build an entirely new project based on one of these, and see what they’re all about.
Pictured above is the result of that effort. An MCS-48 based dual temperature sensor. It uses one or more DS18B20 one-wire bus temperature sensors.
Read more about it here.
Posted in Vintage microcontrollers
I’m building the temperature sensor. Looking forward to using my 8749s!
Send me a picture of it when done!
How critical is the MOSFET selection? I am considering building a second one with 2N7000 and ZVP3306A MOSFETs.
Use whatever you can get your hands on. Is this the chip shortage causing availability problems?
Just don’t resort to transistors. Definitely will not work.
I built the HVEprom to read and write a 8749. It works great.
Has anyone thought of printing a 3D case for it?
I imagine the most difficult part would be how ZIF socket is buried between the components. But at the same time, this could be mitigated by plugging in another ZIF socket to raise it.