Lo-tech 1MB RAM Board (prototype) Resources
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Resources for the r01 (prototype) Lo-tech 1MB RAM Board:
Design
Bill of Materials
| Part | Value | Device | Package | Qty | Farnell | Mouser |
|---|---|---|---|---|---|---|
| C1..C8, C10 | 0.1uF | X7R Ceramic Capacitor | 0603 | 9 | 1414610 | - |
| C11 | 10uF | 16V Electrolytic | E2-5 | 1 | 9451056 | - |
| IC1, IC2 | - | AS6C4008-55SIN 4Mb SRAM | SOIC-32 | 2 | 1562901 | - |
| IC3, IC4 | - | 74HCT138D | SOIC-16 | 2 | 1201307 | - |
| IC5, IC6 | - | 74HCT688DW | SOIC-20 | 2 | 1085321 | - |
| IC7 | - | 74HCT245DW | SOIC-20 | 1 | 1085315 | - |
| IC8 | - | 74HCT04D | SOIC-14 | 1 | 1085299 | - |
| IC10 | - | 74HCT32D | SOIC-14 | 1 | 1201305 | - |
| JP1 | - | PINHD-1X2 | - | 1 | 1593411 | - |
| R1 | 10k | Resistor | 0603 | 1 | 1469748 | - |
| RN1, RN2 | 10k | BOURNS 4609X-101-103LF | SIL-9 | 2 | 2112931 | - |
| SW1, SW2 | - | MULTICOMP MCNDS-08-V | DIP-16 | 2 | 9471596 | - |
Note: There is no C9 or IC9.
DIP Switch Settings
The board is configured via two banks of DIP switches, which control whether each physical segment (=64KB) is active on the memory board.
JP1, when closed, excludes the first 16KB to provide compatibility with the IBM Personal Computer 5150 when the system board is populated with the minimum 16KB RAM. In this way, system memory can be expanded to the full 640KB (plus upper memory).
Switch position ON enables the corresponding page:
| Sw1 | Sw2 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||
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See Also
- Lo-tech 1MB RAM Board (current version)