Similar to the standard Z80 CPU Module, the v2.1 version is essentially a breakout board for the Z80 CPU with all of the signals needed for regular RC2014 use presented on pins on the standard header.
Some signals, such as INT, BUSRQ, WAIT and NMI need to be pulled high for normal operation. The original CPU Module did this with links to the 5v line – however, this meant that modules that needed to use these, such as the SD Memory Dump Module, risked damage to the CPU or module. The v2.1 CPU Module overcomes this by using 10k resistors to pull the signals high, which allows them to be safely pulled low if required.
Click image above for PDF schematic
Instead of presenting these additional lines on a header at the top of the module, they are moved down to the Enhanced Bus, which means that this can be used with the Backplane Pro without having to run additional jumper wires. It will, however, function perectly well with the original Backplane 8
The CPU socket pads are slightly oversized too, so that a ZIF socket can be used if required.
Bill of materials
- Z80 CPU 2.1 PCB
- 40 pin DIL socket
- Zilog Z80 CPU
- 40 pin RA Header
- 100nf
- 10k x 4