Category Archives: Monsputer

Z80 Monsputer: Bus manager and probe

There are 2 new boards for the Z80 Monsputer; one is a bus manager (at top) and the other is a bus probe for a logic analyser. The bus manager can be used for single stepping through the code by … Continue reading

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Z80 Monsputer: CPU board cleanup

I posted some pictures of the Monsputer CPU board, which had numerous ugly patches. By substituting a smaller chip with more pins, I was able to put all the glue logic in the CPLD. Here is the top and bottom … Continue reading

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Point to point wiring with magnet wire

I’m currently rewiring a part of the Monsputer’s CPU board that was implemented with several patches. I’m reusing an Atmel CPLD used for another board. A problem with this chip: it’s a TQFP package. Without a PCB, it’s difficult to … Continue reading

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Z80 Monsputer interconnect

This board does all the interconnect outside the bus connector. It has buffers to make ports 0x50 to 0x53 as tristate buffers. The circuit in the lower section converts ports 50-53 to hexadecimal for a VFD display.

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Z80 Monsputer: CPU board

The Z80 Monsputer has of course a CPU. It went from several iterations of design over the years. This is probably not the last one because of the ugly patches. Z80 CPU running at 4 MHz 6850 main UART 8253 … Continue reading

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Z80 Monsputer GPIO and vectored interrupts

This board is one of the first boards I’ve done for the monsputer. It has only TTL logic on it. I’ve probably made it about 25 years ago (or more!). The chips came from a bunch of PCBs that I … Continue reading

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Z80 Monsputer memory card

This board has: 512k dynamic RAM 4 x 256k EPROM 2 x 128k FLASH 2 x 32k SRAM CPLD for glue logic The CPLD generates all the signals for refreshing the dynamic RAM. It also generates an 8th bit address … Continue reading

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