Z80 in 3 Chips

Features

• Z80
  • 12.5 MHz operation
• 512KB SRAM
• PSoC5LP
  • PSoC5 LP emulates standard Z80 peripheral chips
    • Serial port with USB
  • Memory Management Unit (MMU)
    • Controls 512KB SRAM
  • Loader moves EPROM code to SRAM
  • Controls CPU reset
• Optional MCP23017 16-bit port expander
  • I2C Addresses 0x24
• Optional Front Panel
  • I2C Addresses 0x20-0x23
• SPI interface for SDHC card

Stackup (top to bottom)

• Front Panel For 8 Bit Computers
  • 32 LEDs
  • 32 pushbutton switches
  • I2C interface
• Z80 in 3 Chips (this card)
• SD_CARD_X49 mounted on CARRIER95TO49MM
• JOYPAD

Connectors

H1 - I2C Interface

• Connects to Front Panel Card via I2C

H2 - ISP Download

• Connects to PSoC programmer

H3- Serial Port or SPI (SD Card)

H4 - I/O

J1 - USB B

• 5V card Power
• USB to Serial comm port

J2, J3 - I/O Ports

• J3 connects to JOYPAD

J4 - Audio Out

• DAC is the Analog function generator in the PSoC

J5 - Z80 Signals

• Useful for monitoring the CPU lines

Software

• Hardware/Software options are set in the PSoC "Hardware_Config.h" file
  • Comment out all but one choice
• Options
  • GRANT_9_CHIP_Z80
  • GRANT_7_CHIP_Z80
  • GRANT_7_CHIP_Z80_STANDALONE
  • GRANT_FPGA_CPM
  • MULTIBOOT_CPM

Front Panel

Z80_PSoC Monitor

• Press SW26 button (one in from upper left) button on Front Panel For 8 Bit Computers to run the Monitor
• PSoC Code Github repo

• Type to check the SD card

R4000

• Result:

Multiboot Multicomp

• Insert "M/CPM 512KB" SD card
• Press SW25 (upper left button) on Front Panel For 8 Bit Computers to run Multiboot software
• Z80 NASCOM BASIC
• CP/M Multiboot - Runs MultiComp 512KB SRAM version
  • CP/M 2.2, CP/M 3.0, BASIC
  • SBC-2G-512 on Retrobrewing site - Original author
  • GitHub copy of SBC-2G-512

Reference Designs

• Z80 Reference Designs

Hackaday Page

• Hackaday Page

Assembly Sheet

• Z80 in 3 Chips Assembly Sheet