Category Archives: Z80

Assembler trick: inline strings

Quite often, we need to send strings to a computer. Usually, there is a section in your code where you define the message with a label: ;string is terminated with null MsgHelloWorld: .asciz “Hello World!\r\n” ;subroutine to print strings putstr: … Continue reading

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Altera Quartus, combining Verilog and VHDL

In my previous post, I ported the Multicomp from Grant Searle to an Altera Cyclone II FPGA platform. The Multicomp peripheral are quite minimal, and I wished to use the on board facilities. Code for these were supplied in Verilog. … Continue reading

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Z80 Basic computer on a FPGA

I bought an Altera Cyclone FPGA RCQ208 development board (clone) on eBay a while ago. I ported the Multicomp project from Grant Searle for this platform.This is a minimal port: 1K internal RAM, a single UART, no video but support … Continue reading

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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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Monsputer Serial Card

This card has several protocols: CAN (SJA1000) I²C (PCF8584) Serial (16550,6852) Parallel Port (CPLD) SPI (CPLD) External ports There are 2 CPLDs: ATF1504 parallel port ATF1508 SPI,vectored interrupts 10-1F, glue logic Here’s a look of the other side: I use … Continue reading

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