Z280 - 512K

[Tadeusz Pycio]

A variation of my "Z280 MPU with bootstrap" module is being developed, this time with 512kB RAM on the module. The external address bus has been reduced to only support I/O circuits, and an optional RESET button has been added. This results in the one available boot mode being a serial bootstap from the EEPROM contained in the microcontroller. As with the previous model, I envisage that the EEPROM contents can be updated after booting (jumper PROG).

[Richard Deane]

How is your z280-512k progressing? When complete I am keen to get the gerbers, use jlcpcb to get pcbs, and construct a version.

Good luck with finishing it.

Richard

On Wed, 28 Feb 2024 at 19:56, Tadeusz Pycio <ta...@wp.pl> wrote:

A variation of my "Z280 MPU with bootstrap" module is being developed, this time with 512kB RAM on the module. The external address bus has been reduced to only support I/O circuits, and an optional RESET button has been added. This results in the one available boot mode being a serial bootstap from the EEPROM contained in the microcontroller. As with the previous model, I envisage that the EEPROM contents can be updated after booting (jumper PROG).

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[Tadeusz Pycio]

I am awaiting a shipment that is still in China. As soon as I receive the PCB I will assemble it and check the operation.  If I haven't made some silly mistake this module should work. I will start adapting the microcontroller software after this check of the module, i.e. updating the EEPROM contents with the Z280 bootloader without pulling it out of the module. I would like the process of updating the contents of the microcontroller's EEPROM via the serial port to be independent of the baudrate used by the Z280.

[Paul de Bak]

Thanks Tadeusz for the update. Hope it goes well :)

Paul

On Mon, 1 Apr 2024 at 23:30, Tadeusz Pycio <ta...@wp.pl> wrote:

I am awaiting a shipment that is still in China. As soon as I receive the PCB I will assemble it and check the operation.  If I haven't made some silly mistake this module should work. I will start adapting the microcontroller software after this check of the module, i.e. updating the EEPROM contents with the Z280 bootloader without pulling it out of the module. I would like the process of updating the contents of the microcontroller's EEPROM via the serial port to be independent of the baudrate used by the Z280.

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[Tadeusz Pycio]

Module assembled, basic tests performed (boot, CP/M 2.2). It remains to check in RomWBW environment and add EEPROM upgrade routines.

[Tadeusz Pycio]

Z280 projects have been made available on GitHub

[Jaap van Ganswijk]

Very interesting! But what would a complete system cost? I also started designing a Z280 SBC on EasyEDA, but I'd rather buy a ready PCB, preferably a SBC. I already got some Z280's...

On Sun, 1 Jun 2025, 14:34 Tadeusz Pycio, <ta...@wp.pl> wrote:

Z280 projects have been made available on GitHub

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[Bill Shen]

 Z280 is highly integrated and used Z280 is quite cheap so you should be able to build a SBC for about $20

Bill