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Choosing a memory chip that works with the Z88 is important. Manufactures and the availability of chips change. See Memory Chips for the most 'up-to-date' results.

RAM chips

There are 3 types of RAM chips

• Static RAM
• Pseudo Static RAM
• RAM that should work but doesn't

Modern Static RAM chips are top of the list. They are now manufactured in smaller packages rather than the DIL packages that are used on the Z88 Motherboard and some external cards. unbelievable low current consumption when compared to the RAM chips used in the 1980's give longer battery life. Fortunately, PCB Footprint Converter are available. This allows these smaller size chips to be used now with the Z88.

Pseudo Static RAM chips were used in the 1980s as true static RAM was expensive. From the outside they appear to be like static RAM but internally they have a clock chip that need to refresh the memory before it forgets the value. This overhead means that the chips will need more power than true static RAM.

There are some RAM chips that according to the application or data sheets should work, but don't. They are only found by trying them and the reason why they don't work will remain unknown.

PCB Footprint Converters

To aid construction, these converters may be used to allow the new surface mount devices to be used as larger devices. Let's face it, DIL or DIP packages are a lot easier to handle and solder. These converters may be used to 'bridge that gap.' Here is an example:-

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32 pin SOIC to DIL PCB

External RAM (fitted in the card slot)

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	Amplia un cartucho de Z88 hasta 512Kbytes - Convert 32K RAM card to 512K RAM The memory chip described in the article above is no longer available. Suitable replacements are listed below..
	CYPRESS SEMICONDUCTOR - CY62158ELL-45ZSXI - SRAM, 8MBIT, PARALLEL, 45NS, 44TSOP This memory chip is being used in the Rakewell's Flash/RAM card successfully. TESTED OK
	ALLIANCE MEMORY - AS6C8008-55ZIN - SRAM, 8MB, 2.7-5.5V, 1024KX8, TSOP44 TESTED FAILS
	LYONTEK - LY62W10248ML-55LLI - SRAM, 8M, 1MX8, 2.7-5.5V, 44TSOPII This memory chip is a 'drop-in' replacement for the BSI chip (see below). TESTED FAILS when loading a file in PipeDream.
	BSI (BRILLIANCE SEMICONDUCTOR) - BS62LV8001EIP55 - IC, SRAM 8M, 1024KX8, 2.4-5.5V, SMD This memory chip has been used in the Rakewell's Flash/RAM card successfully. TESTED OK This part is no longer manufactured.

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	Amplia un cartucho de Z88 hasta 512Kbytes - Convert 32K RAM card to 512K RAM The memory chip described in the article above is no longer available. Suitable replacements are listed below.
	ALLIANCE MEMORY - AS6C4008-55SIN - SRAM, 4MB, 2.7V-5.5V, 512KX8, SOP32 Note: This has not been tested.

Internal RAM

The internal 32K of RAM is not large enough. Upgrading this to 128K or 512K internally is possible, but the original 'built-in' OZ operating system did not use this correctly.

Cambridge Computer commissioned OZ 4.0 ROM and were planning to use this with the new User Guide v3 but only the User Guide was changed. The new ROM was made available to users through the Z88 User Group.

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