The Z88 only came with 32K of internal RAM. This is not enough memory for every day use.
The memory can be increased two different ways.
- Internally - by changing the 32K RAM chip
- Externally - by changing the RAM chip in an external card.
Which ever one you wish to use, choosing a memory chip that works with the Z88 is important. This is an ever changing market, manufactures and chips come and go.
1M RAM
The memory chip described in the article below is no longer available. A suitable replacement are listed. 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. Amplia un cartucho de Z88 hasta 512Kbytes - Convert 32K RAM card to 512K RAM | |
CYPRESS SEMICONDUCTOR - CY62158ELL-45ZSXI - SRAM, 8MBIT, PARALLEL, 45NS, 44TSOP 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. | |
This memory chip is a 'drop-in' replacement for the BSI chip (see below). It currently fails in PipeDream OZ 4.2. More testing is required. LYONTEK - LY62W10248ML-55LLI - SRAM, 8M, 1MX8, 2.7-5.5V, 44TSOPII | |
This memory chip has been used in the Rakewell's Flash/RAM card successfully. This part is no longer manufactured. BSI (BRILLIANCE SEMICONDUCTOR) - BS62LV8001EIP55 - IC, SRAM 8M, 1024KX8, 2.4-5.5V, SMD |
Technical Spec of a Flash and RAM chips
Z80 4MHz | AS6C8008 | ||||||
---|---|---|---|---|---|---|---|
Supply Voltage Min | V | 2.4 | 2.7 | 2.7 | 4.5 | ||
Supply Voltage Typ | V | - | 3.0 | 3.0 | 5.0 | ||
Supply Voltage Max | V | 5.5 | 5.5 | 5.5 | 5.5 | ||
Input High Voltage | V | 2.2 to VCC | 0.7 x VCC min to VCC+0.3 | 2.2 to VCC+0.3 | 2.4 to VCC+0.3 | 2.4 to VCC+0.5 | 2.2 to VCC + 0.5 V |
Input Low Voltage | V | -0.3 to 0.8 | 0.5 to 0.8 | -0.5 to 0.8 | - 0.2 to 0.6 | - 0.2 to 0.6 | –0.5 to 0.8 |
Output High Voltage | V | 2.4 min | 0.85 x VCC | 2.4 min | 2.4 min | 2.4 min | |
Output Low Voltage | V | 0.4 max | 0.45 | 0.4 max | 0.4 max | 0.4 max | |
Standby Power | uA | 1 | 3.5 to 50 | 6 to 80 | 10 to 50 | 2 to 8 | |
Power Consumption | mA | 20 - 40 | 39 | 60 | 30 to 60 | 1.8 to 3 | |
VCC for Data Retention | V | 1.5 | 2.0 | 1.5 | 2.0 | ||
Read Timings | |||||||
Read Cycle Time tRC | ns | 55 min | 55 min | 55 min | 55 min | 45 min | |
Address Access Time tAA | 55 min | 55 max | 55 max | 55 max | 45 max | ||
Chip Enable Access Time tACE | 55 min | 55 max | 55 max | 55 max | 45 max | ||
Output Enable Access Time tOE | 30 max | 25 max | 30 max | 30 max | 22 max | ||
Chip Enable to Output in Low-Z tCLZ | 18 min | 10 min | 10 min | 10 min | 5 min | ||
Output Enable to Output in Low-Z tOLZ | 18 min | 10 min | 5 min | 5 min | 10 min | ||
Chip Disable to Output in High-Z tCHZ | 30 max | 20 max | 20 max | 18 max | |||
Output Disable to Output in High-Z tOHZ | 25 max | 20 max | 20 max | 18 max | |||
Output Hold from Address Change tOH | 0 | 10 min | 10 min | 10 min | 10 min | ||
Write Timings | |||||||
Write Cycle Time tWC | 55 min | 55 min | 55 min | 55 min | 45 min | ||
Address Valid to End of Write tAW | 40 min | 40 min | 50 min | 50 min | 35 min | ||
Chip Enable to End of Write tCW | 0 | 50 min | 50 min | 35 min | |||
Address Set-up Time tAS | 0 | 40 min | 0 | 0 | 35 min | ||
Write Pulse Width tWP | 20 min | 30 min | 45 min | 45 min | 35 min | ||
Write Recovery Time tWR | 0 | 0 | 0 | 0 | |||
Data to Write Time Overlap tDW | 25 min | 25 min | 25 min | 25 min | 25 min | ||
Data Hold from End of Write Time tDH | 0 | 0 | 0 | 0 | 0 | ||
Data Setup to Write End | 25 min | ||||||
Output Active from End of Write tOW | 5 min | 5 min | 5 min | ||||
Write to Output in High-Z tWHZ | 25 max | 20 max | 20 max | 10 max | |||
THE Z80 CPU : TIMING |
512K RAM
The memory chip described in the article below is no longer available. A suitable replacement may be 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. Amplia un cartucho de Z88 hasta 512Kbytes - Convert 32K RAM card to 512K RAM |
Internal RAM
The memory chip described in the article below is no longer available. A suitable replacement may be ALLIANCE MEMORY - AS6C4008-55PCN - SRAM, 4MB, 2.7V-5.5V, 512KX8, PDIP32 This has not been tested yet | |
The memory chip described in this article below is no longer available. A suitable replacement may be ALLIANCE MEMORY - AS6C4008-55SIN - SRAM, 4MB, 2.7V-5.5V, 512KX8, SOP32 This has not been tested yet | |
The memory chip described in the article below is no longer available. A suitable replacement may be ALLIANCE MEMORY - AS6C1008-55PCN - SRAM, 1MB, 2.7V-5.5V, 128KX8, PDIP32 This has not been tested yet |