2 layers87.6 × 73 mm Stemcell panel, the printed circuit board in 3D

Stemcell panel

STM32F4 breakout board in pro micro pinout. Designed mainly for ergo split keyboards.

Size: 87.6 × 73 mm
Copper layers: 2
Thickness: 1.6 mm
Parts: 258
Nets: 56
Pads: 1,650
Tracks, vias: 2,340, 348
Pours: 7
Routed: Yes
KiCad: KiCad 6 (file 20211014)
Created: 16 Jan 2022
Updated: 6 Sep 2022

Overview

Stemcell panel is an open-source printed circuit board by megamind4089, from the megamind4089/STeMCell repository on GitHub. It is a 2-layer board of 87.6 × 73 mm with 258 parts on 56 nets, routed with 2,340 tracks and 348 vias.

It is built around the XC6220B331MR and B5819W. Its parts include 72 capacitors, 48 resistors, 24 connectors, 12 ICs and 12 diodes. It belongs with the keyboards and input boards and the STM32 and AVR (ATmega, ATtiny) boards of this library.

Main components

README

README.md

STeMCell

STM32 breakout in promicro footprint

Features:

Pro micro footprint
STM32F4x1 series MCU
Two layer PCB
Support half duplex USART communication in any of D0, D1, D2, D3 using jumpers
Onboard switch to enable/disable USB DFU bootloader
Inbuilt TX pullup for UART half duplex communication
User LED on PA8
Extra 5 pinout on bottom like Elite C
Supports QMK and ZMK
JLCPCB assembly supported

v2.1.0

front back

Parts

258

Qty	Value	Footprint	References
36			, 1, 2, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22 +20
36	100n	Capacitor_SMD:C_0402_1005Metric	C4, C4, C4, C4, C4, C4, C5, C5, C5, C5, C12, C12, C12, C12, C12, C12 +20
18	10k	Resistor_SMD:R_0402_1005Metric	R6, R6, R6, R6, R6, R6, R7, R7, R7, R7, R7, R7, R8, R8, R8, R8 +2
18	4.7u	Capacitor_SMD:C_0402_1005Metric	C2, C2, C2, C2, C2, C2, C3, C3, C3, C3, C3, C3, C9, C9, C9, C9 +2
12	20p	Capacitor_SMD:C_0402_1005Metric	C10, C10, C10, C10, C10, C10, C11, C11, C11, C11, C11, C11
12	5k1	Resistor_SMD:R_0402_1005Metric	R2, R2, R2, R2, R2, R2, R3, R3, R3, R3, R3, R3
6	10u	Capacitor_SMD:C_0402_1005Metric	C1, C1, C1, C1, C1, C1
6	1A Fuse	Fuse:Fuse_0805_2012Metric	F1, F1, F1, F1, F1, F1
6	220	Resistor_SMD:R_0402_1005Metric	R1, R1, R1, R1, R1, R1
6	2k2	Resistor_SMD:R_0402_1005Metric	R4, R4, R4, R4, R4, R4
6	4.7k	Resistor_SMD:R_0402_1005Metric	R5, R5, R5, R5, R5, R5
6	B5819W	Diode_SMD:D_SOD-123	D2, D2, D2, D2, D2, D2
6	Boot0	Button_Switch_SMD:SW_SPST_CK_KXT3	SW1, SW1, SW1, SW1, SW1, SW1
6	Down	stemcell:Pins5_castellated	J4, J4, J4, J4, J4, J4
6	G***	kibuzzard-620B7294	kibuzzard-620B7294, kibuzzard-620B7294, kibuzzard-620B7294, kibuzzard-620B7294, kibuzzard-620B7294, kibuzzard-620B7294
6	HSE1 8Mhz 12pF	Crystal:Crystal_SMD_3225-4Pin_3.2x2.5mm	Y1, Y1, Y1, Y1, Y1, Y1
6	LED	LED_SMD:LED_0402_1005Metric	D1, D1, D1, D1, D1, D1
6	Left	stemcell:Pins12_castellated	J2, J2, J2, J2, J2, J2
6	RX0	stemcell:SOLDER_JUMPER_3	JP2, JP2, JP2, JP2, JP2, JP2
6	Right	stemcell:Pins12_castellated	J3, J3, J3, J3, J3, J3
6	SCL	stemcell:SOLDER_JUMPER_3	JP4, JP4, JP4, JP4, JP4, JP4
6	SDA	stemcell:SOLDER_JUMPER_3	JP3, JP3, JP3, JP3, JP3, JP3
6	STM32F4x1CxUx	Package_DFN_QFN:QFN-48-1EP_7x7mm_P0.5mm_EP5.6x5.6mm	U1, U1, U1, U1, U1, U1
6	TX PUp	stemcell:SOLDER_JUMPER_3	JP5, JP5, JP5, JP5, JP5, JP5
6	TX0	stemcell:SOLDER_JUMPER_3	JP1, JP1, JP1, JP1, JP1, JP1
6	USB C Connector	stemcell:USB-C-C168688	J1, J1, J1, J1, J1, J1
6	XC6220B331MR	Package_TO_SOT_SMD:SOT-23-5	U2, U2, U2, U2, U2, U2

Questions

How big is the Stemcell panel PCB?

It measures 87.6 × 73 mm and has 2 copper layers, 1.6 mm thick.

What parts does the Stemcell panel use?

258 parts, built around the XC6220B331MR and B5819W. 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 Stemcell panel KiCad files?

From the megamind4089/STeMCell repository on GitHub, at the commit this page was made from: the board is panel/stemcell-panel.kicad_pcb and its schematic stemcell.kicad_sch. PCBKit opens the board in the browser, with nothing to install.

Can I use the Stemcell panel design in my own project?

Its repository states no licence, so its author keeps all rights: ask megamind4089 before reusing the design.

Category and platform

Keyboards and input STM32 AVR (ATmega, ATtiny)

Topics

ergonomic-keyboard ergo promicro stm32f4 stm32

Project files

Show this board on your page

A live frame, for any web page

<iframe src="https://pcbkit.io/embed/boards/megamind4089-stemcell-stemcell-panel" title="Stemcell panel in PCBKit" width="100%" height="480" style="border:0;border-radius:12px" allow="fullscreen" loading="lazy"></iframe>

A picture

<img src="https://pcbkit.io/embed/boards/megamind4089-stemcell-stemcell-panel.jpg" alt="Stemcell panel" width="1200" height="900">

A picture that opens the board, for a README

[![Stemcell panel](https://pcbkit.io/embed/boards/megamind4089-stemcell-stemcell-panel.jpg?size=s)](https://pcbkit.io/boards/megamind4089-stemcell-stemcell-panel)

Source

Repository: megamind4089/STeMCell
Board file: panel/stemcell-panel.kicad_pcb
Commit: c96bd62
Homepage: megamind4089.github.io/STeMCell
Licence: Not stated

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