32K RAM

A single 62256 Static RAM chip provides 32K of memory to the Z80.  Address line A15 goes through a NOT gate on a 74LS04 to the /CE pin, thus mapping this memory to address 0x8000 – 0xFFFF.  The /WE and /OE lines are controlled by ORing the /MREQ with the /WR or /RD from the Z80

RAM Front

Click the image below for schematics in PDF format

SCM_32KRAM

Only 1 of the 6 NOT gates on the 74LS04 is used, which is wasteful

RAM_Tindie

Buy one here

Bill of materials

  • 34 pin RA Header
  • 28 pin wide DIL socket
  • 14 pin narrow DIL socket
  • 74LS32
  • 74LS04
  • 62256 RAM
1 Comment
  1. […] RAM – a 62256 static RAM (32kb) supported by a couple of 74HCT series TTL chips […]