LB-MEM-02

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Revision as of 15:02, 7 September 2024 by Blwikiadmin (talk | contribs) (→‎Rev 2)
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LB-MEM-02 P1660-720px.jpg


Features

  • 32KB SRAM
  • 16KB EPROM
    • Headers to select PROM bank
  • Connects to Address/Data and Memory control lines
  • 50x75mm card

Design

SRAM

LB-MEM-02-SRAM.PNG

EPROM

LB-MEM-02-PROM.PNG

  • LB-65CXX-01 card has 16 KB PROM from 0xC000-0xFFFF
  • LB-6802-01 card has 16 KB PROM from 0xC000-0xFFFF
  • LB-6809-01 card has 16 KB PROM from 0xC000-0xFFFF
  • LB-Z80-01 card has 8KB PROM from 0x0000-0x1FFF (upper 8KB is not used)

Parts/Jumpers

LB-MEM-02 REV1 MECH Ann.png

27C256/27C512 EPROMs

  • Card has a 16KB size from the CPU
  • 27C256 (32KB) and 27C512 (64KB) Flash EPROMs are commonly available
  • Jumpers allow firmware banks to be selected
    • 2 banks in 27C256
    • 4 banks in 27C512

LB-MEM-03 EPROM 27C256 512.PNG

Backplane Connector

LB-MEM-02-BKPL.PNG

Mechanicals

Rev 3

Rev 2

LB-MEM-02 Rev2 MECH.PNG

Rev 1

LB-MEM-02 REV1 MECH.PNG

Checkout

Rev 2

  • Flips 74HC04
  • Missing PWR and GND on U1 (74HC04)
  • Test using ramLoop.asm and no SRAM
    • Works on 6809 Emulator but always passes there
      • Controls/data look OK
      • Forcing an error works

Rev 1

  • GND is missing from U1-7

Assembly Sheet

Rev 1

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