Bill of Materials (TTL Buffer Boards)
This page lists the parts needed by the TTL buffer boards for use with the 6-12 bit boards (by IanB)
These boards are not essential as you can connect directly to the 12 way header on the main board. However they perform two functions:
- They buffer the signals and protect the CPLD from damage
- They bring their connectors to the outside of the recommended case so that leads for different computers can be easily swapped.
The latest gerbers are here:
- 3 bit TTL
- PC EGA/CGA/MDA TTL
- 6 bit TTL Not recommended for 12 bit boards
- 8 bit TTL Not recommended for 12 bit boards
| Part Description | Supplier | Quantity | Part Ref | Min Order | Notes |
|---|---|---|---|---|---|
| 4K7 0805 Resistor | RS 905-2924 | 4 off | R1-4 | 50 | R5 Not fitted |
| 100nf 0805 Multilayer Ceramic Capacitor | RS 464‑6688 | 1 off | C1 | 50 | working voltage ≥ 10V |
| Schottky diode MBR130LSFT1G | Farnell 2463407 | 1 off | D1 | 5 | SOD-123FL package |
| 74LS08 TTL | Farnell 1287549 | 1 off | U1 | 1 | SOIC package |
| Samtec SSW-106-02-T-D-RA 2x6 way 0.1" female right angle PCB Header | Farnell 2779580 | 1 off | P1 | 1 | |
| Samtec TLW-104-06-T-S 1x4 way male header | RS 198-2815 | 1 off | P2 | 1 | Long side of pins goes in PCB |
| Samtec TLW-101-06-T-S 1x1 way male header | RS 198-2806 | 2 off | P6, P7 | 1 | P6 & P7 should be trimmed flush with the plastic to act as support/spacers (see photo) |
| 6 Way IDC header (vertical) | Farnell 2215302 | 1 off | P4 | 10 |
| Part Description | Supplier | Quantity | Part Ref | Min Order | Notes |
|---|---|---|---|---|---|
| 100nf 0805 Multilayer Ceramic Capacitor | RS 464‑6688 | 1 off | C1 | 50 | working voltage ≥ 10V |
| Bourns 4605X-101-472LF 4K7 x 4 Resistor Network | Farnell 9356100 | 2 off | RN1-2 | 1 | |
| 74LS245 TTL | Farnell 1287549 | 1 off | U1 | 1 | SOIC package |
| Samtec SSW-106-02-T-D-RA 2x6 way 0.1" female right angle PCB Header | Farnell 2779580 | 1 off | P1 | 1 | |
| Samtec TLW-104-06-T-S 1x4 way male header | RS 198-2815 | 1 off | P2 | 1 | Long side of pins goes in PCB |
| Samtec TLW-101-06-T-S 1x1 way male header | RS 198-2806 | 2 off | P6, P7 | 1 | P6 & P7 should be trimmed flush with the plastic to act as support/spacers (see photo) |
| 9 way D-sub female | Farnell 1084678 | 1 off | P4 | 5 |
| Part Description | Supplier | Quantity | Part Ref | Min Order | Notes |
|---|---|---|---|---|---|
| 100nf 0805 Multilayer Ceramic Capacitor | RS 464‑6688 | 1 off | C1 | 50 | working voltage ≥ 10V |
| Bourns 4605X-101-472LF 4K7 x 4 Resistor Network | Farnell 9356100 | 2 off | RN1-2 | 1 | |
| Schottky diode MBR130LSFT1G | Farnell 2463407 | 1 off | D1 | 5 | SOD-123FL package |
| 74LS245 TTL | Farnell 1287549 | 1 off | U1 | 1 | SOIC package |
| Samtec SSW-106-02-T-D-RA 2x6 way 0.1" female right angle PCB Header | Farnell 2779580 | 1 off | P1 | 1 | |
| Samtec TLW-104-06-T-S 1x4 way male header | RS 198-2815 | 1 off | P2 | 1 | Long side of pins goes in PCB |
| Samtec TLW-101-06-T-S 1x1 way male header | RS 198-2806 | 2 off | P6, P7 | 1 | P6 & P7 should be trimmed flush with the plastic to act as support/spacers (see photo) |
| 10 Way IDC header (vertical) | Farnell 2843527 | 1 off | P4 | 10 |
| Part Description | Supplier | Quantity | Part Ref | Min Order | Notes |
|---|---|---|---|---|---|
| 100nf 0805 Multilayer Ceramic Capacitor | RS 464‑6688 | 2 off | C1-2 | 50 | working voltage ≥ 10V |
| Bourns 4606X-101-472LF 4K7 x 5 Resistor Network | Farnell 9356240 | 2 off | RN1-2 | 1 | |
| Schottky diode MBR130LSFT1G | Farnell 2463407 | 1 off | D1 | 5 | SOD-123FL package |
| 74LS245 TTL | Farnell 1287549 | 1 off | U1 | 1 | SOIC package |
| 74LS08 TTL | Farnell 1287549 | 1 off | U2 | 1 | SOIC package |
| Samtec SSW-106-02-T-D-RA 2x6 way 0.1" female right angle PCB Header | Farnell 2779580 | 1 off | P1 | 1 | |
| Samtec TLW-104-06-T-S 1x4 way male header | RS 198-2815 | 1 off | P2 | 1 | Long side of pins goes in PCB |
| Samtec TLW-101-06-T-S 1x1 way male header | RS 198-2806 | 2 off | P6, P7 | 1 | P6 & P7 should be trimmed flush with the plastic to act as support/spacers (see photo) |
| 12 Way IDC header (vertical) | Farnell 2843528 | 1 off | P4 | 10 |
The cable assembly will vary with each board and will require a matching IDC connector and ribbon cable plus an appropriate connector for the computer. A standard 9 way CGA/EGA/MDA cable should plug into the PC buffer board.
Note after trimming their pins as mentioned above, P6 and P7 act as feet and rest on top of the Pi zero's camera connector to stop P2 on the buffer boards from falling out of its socket if you push down on their external connectors which might result in the bottom of the buffer boards shorting against components on the Pi zero.