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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 replacement are listed below.

Rakewell will be selling their Flash/RAM PCB. This may be used instead of modifying the original 32K PCB board. This would upgrade the card to 1M.

Note: This chip will be tested, results will follow.

ALLIANCE MEMORY - AS6C8008-55ZIN - SRAM, 8MB, 2.7-5.5V, 1024KX8, TSOP44

Note: This chip will be tested, results will follow.

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.

Manufacture response:-

We have read the information on web-site provided from customer. Just as customer said, yes, the circuit diagram is pretty straightforward. We can not  find an problem from that. Just we know, the major differences between our parts and BSI's are the design on ESD protection devices, shown as below. We use type 2 on our parts, but BSI uses type 1 without using P-diode,Dp. We wondered  if this could be the issue. Maybe, we need to make some tests on customer's AP board to learn the real situations.

My response :-

Sorry about the delay in replying but I have been comparing the specs between both these chips and running more tests.

Where do we go from here?

I just can’t believe it is a timing issue because the Z80 is running at 3.2768 Mhz. A read or write command takes 3 clock cycles. This gives 915.52734375 nS and the device only needs 55.

How can we test and see what is happening? Have you got any suitable test equipment?

This memory chip has been used in the Rakewell's Flash/RAM card successfully.

TESTED OK

This part is no longer manufactured.

BSI (BRILLIANCE SEMICONDUCTOR) - BS62LV8001EIP55 - IC, SRAM 8M, 1024KX8, 2.4-5.5V, SMD

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.

Rakewell will be selling their Flash/RAM PCB. This may be used instead of modifying the original 32K PCB board. This would upgrade the card to 1M.

Z88 32kb to 512kb Memory Upgrade

The memory chip described in the article above is no longer available. Suitable replacements are listed below.

ALLIANCE MEMORY - AS6C4008-55PCN - SRAM, 4MB, 2.7V-5.5V, 512KX8, PDIP32

This has not been tested yet

Wide internally your Z88 to 512Kbytes

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

This has not been tested yet

Z88 32kb to 128K Upgrade

The memory chip described in the article above is no longer available. Suitable replacements are listed below.

ALLIANCE MEMORY - AS6C1008-55PCN - SRAM, 1MB, 2.7V-5.5V, 128KX8, PDIP32

This has not been tested yet