2 layers30.5 × 48.3 mm
SoftSwitch
btb/80ColumnCard
An Apple II 80-Column Card. Based on the Videx Videoterm
17 parts43Apache-2.0
2 layers155.2 × 78.6 mm
80ColumnCard
btb/80ColumnCard43An Apple II 80-Column Card. Based on the Videx Videoterm
- Size
- 155.2 × 78.6 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 47
- Nets
- 168
- Pads
- 646
- Tracks, vias
- 971, 49
- Routed
- Yes
- KiCad
- KiCad 7 (file 20221018)
- Created
- 19 Sep 2022
- Updated
- 14 Aug 2026
Overview
80ColumnCard is an open-source printed circuit board by btb, from the btb/80ColumnCard repository on GitHub, published under the Apache-2.0 licence. It is a 2-layer board of 155.2 × 78.6 mm with 47 parts on 168 nets, routed with 971 tracks and 49 vias.
It is built around the 74LS245SC, 74LS157PC and 74LS00SC, with the 74LS02PC, 74LS04PC and 74LS139PC among its other parts. Its parts include 26 ICs, 8 resistors, 5 capacitors, 4 crystals and 2 connectors.
Main components
1174LS245SC
-0℃~+70℃ 12ns@5V,45pF 15mA 24mA 4.75V~5.25V 74LS 8 Bidirectional Output enable Schmitt trigger Tri-State - Buffers, Drivers, Receivers, Transceivers ROHSTexas InstrumentsBuffers, Drivers, Receivers, Transceivers
74LS157PC
PDIP-160℃~+70℃ 4.75V~5.25V Single Supply PDIP-16 Signal Switches, Multiplexers, Decoders ROHSTexas InstrumentsSignal Switches, Multiplexers, Decoders
74LS00SC
-0℃~+70℃ 15ns@5V,50pF 2 2.7V 2V 4 4.75V~5.25V 400uA 500mV 74LS 800mV 8mA NAND Gate - Logic Gates ROHSTexas InstrumentsLogic Gates
74LS02PC
DIP-140℃~+70℃ 15ns@5V,15pF 2 2.7V 2V 4 4.75V~5.25V 400uA 500mV 74LS 800mV 8mA 8mA NOR Gate DIP-14 Logic Gates ROHSonsemiLogic Gates74LS04PC
PDIP-140℃~+70℃ 4.75V~5.25V 6 6.6mA 74LS PDIP-14 InvertersonsemiInverters74LS139PC
PDIP-1622ns 74LS 8mA Decoder Single Supply PDIP-16 Signal Switches, Multiplexers, DecodersonsemiSignal Switches, Multiplexers, Decoders
74LS161DC
-0℃~+70℃ 14ns 32MHz 4 4.75V~5.25V 74LS 93mW Asynchronous Binary Counter Programmable divide ratio、Reset function、Cascade counter、Synchronous counting Rising Edge Synchronous - Counters, DividersTexas InstrumentsCounters, Dividers74LS166AP-E
DIP-16-20℃~+75℃ 14ns@5V,15pF 25MHz 4.75V~5.25V 400mW 400uA 74LS 8 8mA Asynchronous clear function Parallel or Serial to Serial DIP-16 Shift Registers ROHSRenesas ElectronicsShift Registers74LS175PC
PDIP-160℃~+70℃ 1 10ns 18mA 25ns@5V,15pF 30MHz 4 4.75V~5.25V 5ns 74LS Series Asynchronous Complementary type D-Type Reset Rising Edge PDIP-16 Flip Flops ROHSTexas InstrumentsFlip Flops
74LS273PC
PDIP-201 15ns 27mA 27ns@5V,15pF 30MHz 5ns 74LS Series 8 D-Type Reset Rising Edge PDIP-20 Flip Flops ROHSonsemiFlip Flops74LS86
DIP-14-20℃~+75℃ 10mA 2.7V 23ns@5V,15pF 2V 400mV 400uA 5V 74LS 800mV 8mA XOR Gate DIP-14 Logic Gates ROHSHITLogic Gates
README
hardware/SoftSwitch/README.mdParts
47| Qty | Value | Footprint | References |
|---|---|---|---|
| 3 | 74LS157 | MyPackages:DIP-16_W7.62mm | U14, U15, U16 |
| 2 | '64 - '512 | Package_DIP:DIP-28_W15.24mm | U3W28, U20B1 |
| 2 | 220 | MyPassives:R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R1, R2 |
| 2 | 4013 | MyPackages:DIP-14_W7.62mm | U7, U8 |
| 1 | '32 - '256 | Package_DIP:DIP-28_W15.24mm | U10W28 |
| 1 | '32 - '256 | Package_DIP:DIP-28_W7.62mm | U10N28 |
| 1 | '512 | Package_DIP:DIP-32_W15.24mm | U10W32 |
| 1 | '512 | Package_DIP:DIP-32_W7.62mm | U10N32 |
| 1 | .1nF | MyPassives:C_Axial_L2.6mm_D1.8mm_P6.35mm_Horizontal | C2 |
| 1 | .1uF | MyPassives:C_Axial_L2.6mm_D1.8mm_P6.35mm_Horizontal | C5 |
| 1 | .1uF | MyPassives:CP_Radial_Tantal_D4.5mm_P6.35mm | C1 |
| 1 | 1.5K | MyPassives:R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R9 |
| 1 | 10 | MyPassives:R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R11 |
| 1 | 150 | MyPassives:R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R12 |
| 1 | 17.430 MHZ | Crystal:Crystal_HC18-U_Horizontal | Y1 |
| 1 | 1K | MyPassives:R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R8 |
| 1 | 1N4148 | Diode_THT:D_DO-35_SOD27_P10.16mm_Horizontal | CR1 |
| 1 | 1nF | MyPassives:C_Axial_L2.6mm_D1.8mm_P6.35mm_Horizontal | C3 |
| 1 | 200 | MyPassives:R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R13 |
| 1 | 2732 | MyPackages:DIP-24_W15.24mm | U20 |
| 1 | 2758/'16/'32 | MyPackages:DIP-24_W15.24mm | U3 |
| 1 | 2K | MyPassives:R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R10 |
| 1 | 2N3904 | Package_TO_SOT_THT:TO-92 | Q1 |
| 1 | 6116 | MyPackages:DIP-24_W7.62mm | U10 |
| 1 | 6116 | MyPackages:DIP-24_W15.24mm | U10W24 |
| 1 | 74LS00 | MyPackages:DIP-14_W7.62mm | U6 |
| 1 | 74LS02 | MyPackages:DIP-14_W7.62mm | U2 |
| 1 | 74LS04 | MyPackages:DIP-14_W7.62mm | U4 |
| 1 | 74LS139 | MyPackages:DIP-16_W7.62mm | U9 |
| 1 | 74LS161 | MyPackages:DIP-16_W7.62mm | U23 |
| 1 | 74LS166 | MyPackages:DIP-16_W7.62mm | U21 |
| 1 | 74LS175 | MyPackages:DIP-16_W7.62mm | U22 |
| 1 | 74LS245 | MyPackages:DIP-20_W7.62mm | U5 |
| 1 | 74LS273 | MyPackages:DIP-20_W7.62mm | U18 |
| 1 | 74LS86 | MyPackages:DIP-14_W7.62mm | U1 |
| 1 | A11/WE | MyPassives:SolderJumper-3_Pie_Bridged12 | X21 |
| 1 | Apple II Expansion Bus | Apple_II:Apple II Expansion Edge Connector | J1 |
| 1 | CHAR INV | MyPassives:SolderJumper-3_Pie_Bridged23 | X6 |
| 1 | MC6845 | MyPackages:DIP-40_W15.24mm | U19 |
| 1 | SCREEN INV | MyPassives:SolderJumper-3_Pie_Bridged23 | X7 |
| 1 | VIDEO & LIGHT PEN | Connector_PinHeader_2.54mm:PinHeader_1x06_P2.54mm_Horizontal | J2 |
| 1 | not placed | MyPassives:CP_Radial_Tantal_D4.5mm_P6.35mm | C4 |
Questions
How big is the 80ColumnCard PCB?
It measures 155.2 × 78.6 mm and has 2 copper layers, 1.6 mm thick.
What parts does the 80ColumnCard use?
47 parts, built around the 74LS245SC, 74LS157PC, 74LS00SC and 74LS02PC. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.
Where can I download the 80ColumnCard KiCad files?
From the btb/80ColumnCard repository on GitHub, at the commit this page was made from: the board is hardware/80ColumnCard/80ColumnCard.kicad_pcb and its schematic hardware/80ColumnCard/80ColumnCard.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the 80ColumnCard design in my own project?
Its repository publishes it under the Apache-2.0 licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).
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