2 layers65.5 × 64.2 mm
2 layers65.5 × 87.3 mm
A2Pico.v2.6
rallepalaveev/a2pico28A2PICO
- Size
- 65.5 × 87.3 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 87
- Nets
- 63
- Pads
- 265
- Tracks, vias
- 627, 161
- Pours
- 6
- Routed
- Yes
- KiCad
- KiCad 8.0 (file 20240108)
- Created
- 26 Aug 2023
- Updated
- 11 Feb 2026
Overview
A2Pico.v2.6 is an open-source printed circuit board by rallepalaveev, from the rallepalaveev/a2pico repository on GitHub, published under the MIT licence. It is a 2-layer board of 65.5 × 87.3 mm with 87 parts on 63 nets, routed with 627 tracks and 161 vias.
It is built around the 74LVC245AD. Its parts include 7 capacitors, 5 resistors, 5 ICs, 3 diodes and 2 connectors. It belongs with the RP2040 boards of this library.
Main components
1README
README.mdA2Pico Reference Hardware
This repository is the home of the A2Pico reference hardware. Please refer to the upstream repository at https://github.com/oliverschmidt/a2pico for general information on A2Pico.
Hardware Revision History
Version 1.4 is the innitial design with 3x 74LVC245 and 1x 74HC08 to prove the concept. However it is obsolete as it does not switch off the Expansion ROM ($C800-$CFFF), which is always available and could cause data bus conlisions if used with other cards that use this memory space.
Version 1.5 switches off the Expansion ROM ($C800-$CFFF) when $CFFF is accessed or when reset is issued, and switches it back on again when the slot memory is accessed (IOSelect).
Version 1.6 combines 3 of the logic chips into a PLD. 74LS08, 74LS133 and 74LS02 are replaced by ATF22V10.
The RPI usage is as follows:
| GPIO | Usage |
|---|---|
| 0 | UART TX |
| 1 | UART RX |
| 2 - 13 | A0 - A11 |
| 14 | R/W |
| 15 - 22 | D0 - D7 |
| 26 | ENBL |
| 27 | IRQ |
| 28 | RES |
Version "n" has support for a MicroSD card with no ExtROM capability.
The RPI usage of the "n" versions is as follows:
| GPIO | Usage |
|---|---|
| 0 | SPI RX |
| 1 | SPI CSn |
| 2 | SPI SCK |
| 3 | SPI TX |
| 4 | NMI |
| 5 - 12 | A0 - A7 |
| 13 | DEVSEL |
| 14 | R/W |
| 15 - 22 | D0 - D7 |
| 26 | ENBL |
| 27 | IRQ |
| 28 | RES |
Version 1.7 is a direct successor of v1.4. Changes are replacing the 7408 by a 7411, data direction is controlled now by the Raspberry Pi Pico, which allows for all memory locations to be emulated, ENBL has an option to be is driven by a voltage divider for minimum latency, a USB "back power" option is included.
The RPI usage is as follows:
| GPIO | Usage |
|---|---|
| 0 | UART TX |
| 1 | DATA dir |
| 2 - 13 | A0 - A11 |
| 14 | R/W |
| 15 - 22 | D0 - D7 |
| 26 | ENBL |
| 27 | IRQ |
| 28 | RES |
Versions 2.4 and 2.5 are a new hardware variant of v1.7 - TH and SMD respectively. The major change is that A0-7 and D0-7 are multiplexed and an SD card interface is added. The RPI usage is as follows:
| GPIO | Usage |
|---|---|
| 0 | UART Tx |
| 1 | UART Rx |
| 2 | ENBL |
| 3 - 10 | AD0 - AD7 |
| 11 - 14 | A8 - A11 |
| 15 | R/W |
| 16 | PHI1 |
| 17 | RES |
| 18 | IRQ |
| 19 | CMD |
| 20 | DAT0 |
| 21 | DAT3 |
| 22 | CLK |
| 26 | AL-OE |
| 27 | D-OE |
| 28 | DDIR |
Parts
87| Qty | Value | Footprint | References |
|---|---|---|---|
| 60 | , , , , , , , , , , , , , , , +44 | ||
| 6 | 100n | Capacitor_THT:C_Disc_D5.0mm_W2.5mm_P5.00mm | C2, C3, C4, C5, C6, C7 |
| 3 | 10k | Resistor_THT:R_Axial_DIN0204_L3.6mm_D1.6mm_P5.08mm_Horizontal | R2, R3, R4 |
| 3 | 74LVC245 | Package_DIP:DIP-20_W7.62mm_Socket | U2, U3, U4 |
| 2 | 1k | Resistor_THT:R_Axial_DIN0204_L3.6mm_D1.6mm_P5.08mm_Horizontal | R1, R5 |
| 2 | D_T-1_P5.08mm_Horizontal | Diode_THT:D_T-1_P5.08mm_Horizontal | D1, D2 |
| 1 | 100mA | Capacitor_THT:C_Disc_D5.0mm_W2.5mm_P5.00mm | Fu2 |
| 1 | 220uF | Capacitor_Tantalum_SMD:CP_EIA-6032-15_Kemet-U | C1 |
| 1 | 500mA | Capacitor_THT:C_Disc_D5.0mm_W2.5mm_P5.00mm | Fu1 |
| 1 | 74F11 | Package_DIP:DIP-14_W7.62mm_Socket | U5 |
| 1 | LED_D1.8mm_W3.3mm_H2.4mm | LED_THT:LED_D1.8mm_W3.3mm_H2.4mm | LED1 |
| 1 | LOGO | LOGO | G*** |
| 1 | Pico / PicoW | RaspberryPI PicoW:RPi_PicoW_SMD_TH | U1 |
| 1 | PinHeader_1x03_P2.54mm_Vertical | Connector_PinHeader_2.54mm:PinHeader_1x03_P2.54mm_Vertical | J1 |
| 1 | PinHeader_1x04_P2.54mm_Horizontal | Connector_PinHeader_2.54mm:PinHeader_1x04_P2.54mm_Horizontal | J2 |
| 1 | TO-92L_Inline_Wide | Package_TO_SOT_THT:TO-92L_Inline_Wide | T1 |
The 86 most common of 87 parts.
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Questions
How big is the A2Pico.v2.6 PCB?
It measures 65.5 × 87.3 mm and has 2 copper layers, 1.6 mm thick.
What parts does the A2Pico.v2.6 use?
87 parts, built around the 74LVC245AD. 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 A2Pico.v2.6 KiCad files?
From the rallepalaveev/a2pico repository on GitHub, at the commit this page was made from: the board is A2Pico.v2.6/A2Pico.v2.6.kicad_pcb and its schematic A2Pico.v1.6/A2Pico.v1.6.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the A2Pico.v2.6 design in my own project?
Its repository publishes it under the MIT licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).