2 layers
LM80C R6
leomil72/LM80C
A Z80-based homebrew computer withTMS9918, AY-3-8910, Z80 CTC, Z80 PIO, and Z80 SIO
153 parts123GPL-3.0
2 layers53.2 × 57.4 mm
KeybJr
climatex/KeybJr10Use any keyboard with the PCjr.
- Size
- 53.2 × 57.4 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 19
- Nets
- 36
- Pads
- 80
- Tracks, vias
- 87, 0
- Pours
- 1
- Routed
- Yes
- KiCad
- KiCad 7 (file 20221018)
- Created
- 21 Mar 2022
- Updated
- 11 Jun 2025
Overview
KeybJr is an open-source printed circuit board by climatex, from the climatex/KeybJr repository on GitHub. It is a 2-layer board of 53.2 × 57.4 mm with 19 parts on 36 nets, routed with 87 tracks and 0 vias.
It is built around the ATMEGA328P-PU and BC337. Its parts include 5 capacitors, 3 resistors, 3 connectors, 2 diodes and 1 IC. It belongs with the AVR (ATmega, ATtiny) boards of this library.
Main components
2
ATMEGA328P-PU
DIP-28-300mil-40℃~+85℃ 1.8V~5.5V 10bit 1KB 20MHz 23 2KB 32KB 8 Bit AVR Built-in FLASH DIP-28-300mil Microcontrollers (MCU/MPU/SOC) ROHSMicrochip TechnologyMicrocontrollers (MCU/MPU/SOC)
BC337
TO-92-31 NPN 100 100MHz 100nA 45V 5V 625mW 700mV 800mA NPN TO-92-3 Bipolar (BJT) ROHSFoshan Blue Rocket ElecBipolar (BJT)
README
README.mdKeybJr
Use any PS/2, AT or XT keyboard with the IBM PCjr, over the infrared or cable.
More information
Check out my website article to learn more!
Parts
19| Qty | Value | Footprint | References |
|---|---|---|---|
| 2 | 100n | Capacitor_THT:C_Disc_D7.5mm_W2.5mm_P5.00mm | C2, C3 |
| 2 | 22p | Capacitor_THT:C_Disc_D7.5mm_W2.5mm_P5.00mm | C4, C5 |
| 2 | LED | LED_THT:LED_D5.0mm_IRGrey | D1, D2 |
| 1 | +5V (if not using J3) | Connector_BarrelJack:BarrelJack_Horizontal | J1 |
| 1 | 100u | Capacitor_THT:CP_Radial_D6.3mm_P2.50mm | C1 |
| 1 | 10k | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R1 |
| 1 | 16 MHz | Crystal:Crystal_HC49-U_Vertical | Q1 |
| 1 | 22 | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R2 |
| 1 | 470 | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R3 |
| 1 | AT/PS2 - XT | Connector_PinHeader_2.54mm:PinHeader_1x03_P2.54mm_Vertical | JP2 |
| 1 | ATmega328P-P | Package_DIP:DIP-28_W7.62mm | U1 |
| 1 | BC337 | Package_TO_SOT_THT:TO-92_Inline | T1 |
| 1 | Mini-DIN 6pin | Connector_MiniDIN:Mini_DIN6_Female_THT | J2 |
| 1 | RESET | Button_Switch_THT:SW_PUSH_6mm | SW1 |
| 1 | infrared - wired | Connector_PinHeader_2.54mm:PinHeader_1x03_P2.54mm_Vertical | JP1 |
| 1 | to PCjr "K" connector | Connector_PinHeader_2.54mm:PinHeader_2x03_P2.54mm_Vertical | J3 |
Questions
How big is the KeybJr PCB?
It measures 53.2 × 57.4 mm and has 2 copper layers, 1.6 mm thick.
What parts does the KeybJr use?
19 parts, built around the ATMEGA328P-PU and BC337. 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 KeybJr KiCad files?
From the climatex/KeybJr repository on GitHub, at the commit this page was made from: the board is Board/KeybJr.kicad_pcb and its schematic Board/KeybJr.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the KeybJr design in my own project?
Its repository states no licence, so its author keeps all rights: ask climatex before reusing the design.
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