ROM Flash

EPROMs were used in the Z88 both for the internal ROM and externally for saving files. These had windows in them that allowed the EPROM to be erased using UV light. They are now supplied as OTP (One Time Program) devices which makes them unsuitable for storing files unless they are required to be a permanent record.

Flashstore was written to allow the Z88 to use Flash chips.

This section shows how the Flash chips can replace EPROMs making it easier to erase the file area.

Flash EPROM

	Rakewell use their 1M / 512K PCB which allows the following cards to be built. 1M RAM, or 1M FLASH, or 512K FLASH, or 512K RAM or 512K RAM/FLASH card. If you are interested in this, please contact Rakewell directly. Circuit Diagram http://tinyurl.com/zzdmxze
	A suitable 512K FLASH chip replacement is AMIC - A29040CL-55F - MEMORY, CMOS, 4MBIT, PLCC-32 Additional wired links are required.
	SPANSION took over the AMD chips and only produced the chip in SO 044—44-Pin Small Outline Package. New PCB required. The 1M Flash chip was then withdrawn from production. Rakewell bought exiting stocks.
	AMD then made an equivalent chip that could be programmed without using the 12v pin. This meant that the cards could be programmed in any slot. Designing a Single Socket Solution for AMD’s Am29F080 and Intel’s 28F008SA
	This is how the Flash cards all started with the 1M INTEL 28F008SA Chips. They were in a TS 040—40-Pin Standard Thin Small Outline Package and could only be programmed in Slot 3, like EPROM cards.

Internal ROM

Cambridge Computer commissioned OZ 4.0 ROM and were planning to use this with the new User Guide v4 but only the User Guide was changed. The new ROM was made available to users through the Z88 User Group.

The OZ version 4 ROM was the starting point for the disassembly of the code for subsequent versions of OZ. These are available in internal and external versions.

Z88 Motherboard

Here are where all the main parts are on the motherboard.

The external connector on the RH side was never used.

Note: On this motherboard the RAM socket is a 24 pin which is big enough for 32K. Later versions had a 28 pin socket fitted.

Motherboard Modifications (128K EPROM or 512K FLASH)

	Articles
	Z88 Motherboard Modifications - (This link has a Norton warning on it 12 Sep 2014 ) The EPROM chip described in the article above is no longer available.
Picture	Device	Operating	Standby
	Internal Z88 ROM TOSHIBA TC571001D-20 Datasheet	1mA	100uA
	A suitable EPROM chip replacement to use if wanting to change the language is ATMEL - AT27C010-70PU - EPROM, OTP, 1MBIT, PDIP-32 Additional wired links are required.	25mA	100μA
	A suitable 512K FLASH chip replacement was AMIC - A29040C-55F - MEMORY, CMOS, 4MBIT, DIP-32 (now obsolete) Additional wired links are required.	20 mA	1μA
	A current suitable 512K FLASH chip replacement is Microchip - SST39SF040-70-4C-PHE - MEMORY, CMOS, 4MBIT, PDIP-32 Additional wired links are required.	10 mA	30μA