Difference between revisions of "LB-MEM-02"

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[[file:LB-MEM-03_EPROM_27C256_512.PNG]]
 
[[file:LB-MEM-03_EPROM_27C256_512.PNG]]
 +
 +
{| class="wikitable"
 +
! EPROM
 +
! SIZE
 +
! BANKS
 +
! J6(A15/P1)
 +
! J2(A14/P27)
 +
! BANK #
 +
! LOAD OFFSET
 +
|-
 +
| 27C128
 +
| 16KB
 +
| 1
 +
| 2-3 (GND)
 +
| 2-3 (GND)
 +
| 1
 +
| 0x0000
 +
|-
 +
| 27C256
 +
| 32KB
 +
| 2
 +
| 2-3 (GND)
 +
| 1-2 (VCC)
 +
| 1
 +
| 0x0000
 +
|-
 +
| 27C256
 +
| 32KB
 +
| 2
 +
| 2-3 (GND)
 +
| 2-3 (GND)
 +
| 2
 +
| 0x4000
 +
|-
 +
| 27C512
 +
| 64KB
 +
| 4
 +
| 2-3 (GND)
 +
| 2-3 (GND)
 +
| 1
 +
| 0x0000
 +
|-
 +
| 27C512
 +
| 64KB
 +
| 4
 +
| 2-3 (GND)
 +
| 1-2 (VCC)
 +
| 2
 +
| 0x4000
 +
|-
 +
| 27C512
 +
| 64KB
 +
| 4
 +
| 1-2 (VCC)
 +
| 2-3 (GND)
 +
| 3
 +
| 0x8000
 +
|-
 +
| 27C512
 +
| 64KB
 +
| 4
 +
| 1-2 (VCC)
 +
| 1-2 (VCC)
 +
| 4
 +
| 0xC000
 +
|-
 +
|}
  
 
=== Backplane Connector ===
 
=== Backplane Connector ===

Revision as of 18:31, 12 September 2024

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

EPROM SIZE BANKS J6(A15/P1) J2(A14/P27) BANK # LOAD OFFSET
27C128 16KB 1 2-3 (GND) 2-3 (GND) 1 0x0000
27C256 32KB 2 2-3 (GND) 1-2 (VCC) 1 0x0000
27C256 32KB 2 2-3 (GND) 2-3 (GND) 2 0x4000
27C512 64KB 4 2-3 (GND) 2-3 (GND) 1 0x0000
27C512 64KB 4 2-3 (GND) 1-2 (VCC) 2 0x4000
27C512 64KB 4 1-2 (VCC) 2-3 (GND) 3 0x8000
27C512 64KB 4 1-2 (VCC) 1-2 (VCC) 4 0xC000

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 3

  • Adds PWR and GND on U1 (74HC04)
  • Adds electrolytic cap footprint

Rev 2

  • Flips 74HC04 orientation
  • Missing PWR and GND on U1 (74HC04)
  • Tested with LB-6809-01 card
    • Works

Rev 1

  • Missing PWR and GND on U1 (74HC04)
    • Added PWR and GND wires to nearest pins with PWR and GND
  • SRAM passes in TL866 in SRAM test mode
  • Test using ramLoop.asm software

Assembly Sheet

Rev 3

Rev 1

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