VCC and crystal

A project log for Gold186

A freeformed computer based on an Intel 80186 with 16 KB eprom, 1 MB ram and a serial port.

matsengmatseng 02/08/2019 at 12:340 Comments

Since I have GND in the outer bigger frame I made a small frame for VCC and hooked it up to the two VCC pins on the CPU. I also added two 100n caps between VCC and GND.

I discovered that I don't have any thru-hole caps in the pF range so I had to improvise a bit by soldering two SMD caps between the pins of the crystal and then hook up a ground wire between the caps.

After adding some 10K pull-ups to the inputs of the CPU that must be held high while running I could got a nice waveform at the clkout pin and a lot of randomly-looking toggling at the combined address/data-bus pins.

So it seems that the CPU is not completely dead at least :-)