Front view of the complete ESD EX80 system

Some time has passed since my last update on my Z80 computer and a lot of things have changed. First, I summarize some specs from the past posts and will not go deeply into details here. You can find more details here: Z80 Single Board Computer, Z80 work in progress.

  • MCU: Z80 (Z8400B) at 7.3728 MHz, NMOS version for no real reason, CMOS would also be ok
  • RAM: 628128 SRAM (128k available with bank switching, see text)
  • ROM: AT28C64 EEPROM, AT28C256 possible (see text)
  • Internal display: 320×240 TFT with ILI9325 controller
  • External video (b/w), 80×25 characters
  • PS/2 Keyboard
  • 1.44 MB floppy disk, compatible with normal PCs
  • CP/M 2.2
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Z80 Single Board Computer

This is another project building a single board computer with an Z80 MCU alongside some RAM and ROM. In contrast to other well known projects I want to utilise an EEPROM which is very easy to handle. I also want to build a computer that works autonomously including an user interface and does not need additional microcontroller or a PC since both would be more powerful than the actual processor.

It is inspired by the SBC project by Grant Searle and therefore runs his modified version of Microsoft BASIC for the NASCOM computer. I further modified it for this SBC.

Before I explain the details, here is the result.


Z80 SBC overview

Z80 SBC overview

The specs are:

  • MCU: Z80 in CMOS (Z84C006) at 7.3728 MHz
  • RAM: 628128 SRAM
  • ROM: AT28C256 EEPROM
  • Display: 320×240 TFT with ILI9325 controller
  • Keyboard with 64 keys
  • Power consumption: 190 mA at 5V

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