HardLabs

Osdev hat

alxhub·osdev-hat·osdev_hat/osdev_hat.kicad_pcb

Osdev hat layout, top view — open source Raspberry Pi board by alxhub

About the Osdev hat

Osdev hat is an open source Raspberry Pi PCB design by alxhub, published on GitHub under the MIT license. It is a 2-layer board measuring 65 × 56.5 mm, with 60 components from 18 distinct parts.

Its main chip is the Raspberry_Pi_4, from the Raspberry Pi family. Other key parts include the TPS25942ARVCT and PCA9555DB. By type, the board carries 29 resistors, 16 diodes, 6 connectors, 6 capacitors and 2 ICs.

It belongs with the dev boards & breakouts designs in this gallery.

From the project

An operating system development HAT for Raspberry Pi

The OSDev HAT is a Raspberry Pi HAT which makes operating system development against the Raspberry Pi as a host significantly easier.

The HAT contains a socket for an ESP32 (I use the Sparkfun ESP32-S3 Thing Plus). The ESP32 is capable of turning the Pi on and off and communicating with it over UART. A custom bootloader based on raspbootin allows the Pi to boot from a kernel loaded from the ESP32.

Osdev hat, from the project README
From the project README

Main components on the Osdev hat

TPS25942ARVCTPCA9555DB

Osdev hat bill of materials (BOM)

60 components, 18 distinct parts.

QtyPartRefs
1
TPS25942ARVCT
U1
1
PCA9555DB
U2
1
Raspberry_Pi_4
J1
1
Conn_01x12_Socket
J2
1
Conn_01x16_Socket
J3
2
Conn_01x04_Socket
J4, J5
1
USB_C_Plug
P1
1
D_Schottky
D_ESP1
16
LED
D1, D2, D3, D4, D5, D6, D7, D8 +8
1
C_Polarized
C1
2
0.1uF
C2, C4
2
1uF
C3, C5
1
?
C6
16
470
R1, R2, R3, R17, R18, R19, R20, R21 +8
2
5.1k
R4, R5
3
100k
R6, R8, R13
6
?
R7, R9, R10, R11, R12, R14
2
10k
R15, R16

Osdev hat design files

The KiCad project lives in the alxhub/osdev-hat repository on GitHub; these links point at the commit this page was built from.

Osdev hat: common questions

What microcontroller does the Osdev hat use?

The Osdev hat is built around the Raspberry_Pi_4, from the Raspberry Pi family.

How big is the Osdev hat?

The Osdev hat measures 65 × 56.5 mm, has 2 copper layers and is 1.6 mm thick.

How many components are on the Osdev hat?

60 components, from 18 distinct parts. The full bill of materials is listed on this page.

Where can I download the Osdev hat design files?

From the alxhub/osdev-hat repository on GitHub, which has the KiCad layout and the schematic; the links under Design files point to each one.

Can I use the Osdev hat design in my own project?

Yes, under the terms of its MIT license, which alxhub chose for the repository.

Can I test firmware for the Osdev hat without the hardware?

Yes. HardLabs builds a simulation of the board from its netlist and BOM, so you can run and debug Raspberry Pi firmware against it before you order a PCB.

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