2 layers170.2 × 170.2 mm
2 layers49 × 49 mm
KeyboardInterface
RomualdRousseau/Miniish1Homebrew 6502 Computer
- Size
- 49 × 49 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 13
- Nets
- 32
- Pads
- 79
- Tracks, vias
- 130, 3
- Pours
- 1
- Routed
- Yes
- KiCad
- KiCad 7 (file 20221018)
- Created
- 14 Nov 2020
- Updated
- 26 May 2026
Overview
KeyboardInterface is an open-source printed circuit board by RomualdRousseau, from the RomualdRousseau/Miniish repository on GitHub, published under the GPL-3.0 licence. It is a 2-layer board of 49 × 49 mm with 13 parts on 32 nets, routed with 130 tracks and 3 vias.
It is built around the 74HC595 and 74HC14. Its parts include 4 capacitors, 3 ICs, 3 connectors, 1 resistor and 1 diode. It belongs with the retro computing and games boards of this library.
Main components
2
74HC595
SOP-16-40℃~+85℃ 1 100ns@5V,50pF 10MHz 2V~6V 74HC 8 Serial-to-Serial or Parallel Tri-State SOP-16 Shift Registers ROHSGRShift Registers
74HC14
SOP-14-40℃~+85℃ 1.9V、3.98V、4.4V、5.48V、5.9V 100mV、260mV、260mV 20uA 25ns@4.5V,50pF 2V~6V 6 74HC Noise suppression function Schmitt trigger SOP-14 Inverters ROHSJSMSEMIInverters
README
README.mdMiniish - Homebrew 6502 Computer
The goal of this project is to build a 8bit game console based on 6502 CPU. The entire project is strongly inspired by the work and videos of Ben Eater, but also Javidx9 and his emulator.
Mother Board
It is basically the same hardware design presented by Ben Eater. I just cleaned up the adress control logic to have as mush of the 32K RAM available.
The address plan is:
0000 --------------------------------
// RAM
8000 --------------------------------
// LO ROM
D000 --------------------------------
// IRQ Status
D100 --------------------------------
// PICTURE PROCESSING UNIT (PORT1B)
D200 --------------------------------
// AUDIO PROCESSING UNIT (PORT2B)
D300 --------------------------------
// I/O
D400 --------------------------------
// Reserved
E000 --------------------------------
// HI ROM
FFFF --------------------------------
Picture Processing Unit (PPU)
VGA Card
The card is built using a FPGA and strongly inspired to the NES PPU and the capability of PICO-8.
The overall specs of the VGA card is 16 colors with a 128x128 display area using the VGA 640x480 60Hz standard. The 16 colors are the PICO8 palette.
The VGA card is interfaced to the motherboard through a sprite based unit. The video ram is not mapped to the computer ram but instead, the CPU sends instructions to a sprite generator very similar to the NES (greatly based on Javidx9 explanations).
The overall spec of the sprite generator is:
-
1 nametables for the background composed of 16 * 16 tiles. Each tile is 8x8 pixels. Scrolling vertical and horizontal modes are supported.
-
256 sprites with tansparency support. Each sprite is also a tile of 8x8 pixels.
-
64 simultaneous sprites on screen and 16 sprites per scanline
-
NMI is generated at each vertical blank
Audio Procesing Unit (APU)
The card is built using a ATMEGA328p at 20Mhz with the library the_synth of Edgar.
The synthetizer has the overall spec:
-
4 channels at 20KHz
-
4 waveforms: triangle, square, sinus + noise
-
4 envelopes
-
modulation
-
IRQ0 is generated as the next data frame callback
Parts
13| Qty | Value | Footprint | References |
|---|---|---|---|
| 4 | 100nF | Capacitor_THT:C_Disc_D5.0mm_W2.5mm_P2.50mm | C1, C2, C3, C4 |
| 2 | 74HC595 | Package_DIP:DIP-16_W7.62mm | U2, U3 |
| 1 | 33K | Resistor_THT:R_Axial_DIN0309_L9.0mm_D3.2mm_P12.70mm_Horizontal | R1 |
| 1 | 74HC14 | Package_DIP:DIP-14_W7.62mm | U1 |
| 1 | CIA | Connector_PinSocket_2.54mm:PinSocket_1x10_P2.54mm_Vertical | J2 |
| 1 | D | Diode_THT:D_A-405_P10.16mm_Horizontal | D1 |
| 1 | LOGO | Cow:VerySmallCow | XiaoNiuNiu |
| 1 | POWER | Connector_PinSocket_2.54mm:PinSocket_1x02_P2.54mm_Vertical | J3 |
| 1 | PS/2 | Connector_MiniDIN:Mini_din6 | J1 |
Questions
How big is the KeyboardInterface PCB?
It measures 49 × 49 mm and has 2 copper layers, 1.6 mm thick.
What parts does the KeyboardInterface use?
13 parts, built around the 74HC595 and 74HC14. 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 KeyboardInterface KiCad files?
From the RomualdRousseau/Miniish repository on GitHub, at the commit this page was made from: the board is Hardware/KeyboardInterface/KeyboardInterface.kicad_pcb and its schematic Hardware/ArduinoMultiInterface/ArduinoMultiInterface.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the KeyboardInterface design in my own project?
Its repository publishes it under the GPL-3.0 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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