4 layers40.3 × 68.8 mm
2 layers41 × 20.3 mm
Flash
fm4dd/pmod-flash1Macronix MX25R6435F SPI Flash PMOD
- Size
- 41 × 20.3 mm
- Copper layers
- 2
- Thickness
- 0.8 mm
- Parts
- 15
- Nets
- 10
- Pads
- 62
- Tracks, vias
- 144, 9
- Pours
- 1
- Routed
- Yes
- KiCad
- KiCad 7 (file 20221018)
- Created
- 1 Oct 2023
- Updated
- 24 Feb 2026
Overview
Flash is an open-source printed circuit board by fm4dd, from the fm4dd/pmod-flash repository on GitHub. It is a 2-layer board of 41 × 20.3 mm with 15 parts on 10 nets, routed with 144 tracks and 9 vias.
It is built around the MX25R6435FZAIL0 and CC0402KRX7R7BB104. Its parts include 6 resistors, 3 capacitors, 2 connectors, 1 IC and 1 inductor. It belongs with the fPGA and programmable logic boards and the FPGA and CPLD boards of this library.
Main components
2README
readme.mdFlash PMOD
Description
This PMOD provides the Macronix MX25R6435F SPI Flash memory in a pass-through PMOD connector board. The MX25R6435F is a 64Mbit (8MByte) Serial NOR Flash that can operate in multiple modes up to 80Mhz Quad SPI. The PMOD includes the option to install a 7-pin 2.54mm pitch testpoint header for signal and protocol analysis.
https://www.mxic.com.tw/en-us/products/NOR-Flash/Pages/Ultra-Low-Power-Flash.aspx
Schematic
PCB Gerber
The PMOD Flash module was designed with KiCad 7
Pin Assignments
| Pinout | Pin | Function | Pin | Function |
|---|---|---|---|---|
 | 1 | CS | 7 | SIO2 |
| 2 | MOSI | 8 | SIO3 | |
| 3 | MISO | 9 | not connected (CS2) | |
| 4 | SCK | 10 | not connected (CS3) | |
| 5 | GND | 11 | GND | |
| 6 | 3V3 | 12 | 3V3 |
Example Code
The following code examples demonstrate the PMOD function for quick verification on various Microcontroller and FPGA platforms.
| Platform | Test Program location | Description |
|---|---|---|
| Arduino | examples/arduino | Flash test adopted from the SparkFun_SPI_SerialFlash library |
| Raspberry | examples/rpi | Linux has the flashrom program for basic read/write commands |
| Gatemate | examples/gatemate | Gatemate FPGA test program for basic Flash access validation |
| iCEBreaker | examples/icebreaker | iCEBreaker FPGA test program for basic Flash access validation |
PMOD-Flash Function Tests
PMOD Flash module connected to the PMOD2RPi board, driven by Seeeduino XIAO SAMD21 MCU:
PMOD Flash module connected to the PMOD2RPi board, interfacing with the Raspberry Pi 4:
PMOD Flash module verified running at 50MHz SPI clock speed with the Raspberry Pi 4:
PMOD Flash module test on Cologne Chip Gatemate FPGA:
Parts
15| Qty | Value | Footprint | References |
|---|---|---|---|
| 6 | 10K | Resistor_SMD:R_0402_1005Metric | R1, R2, R3, R4, R5, R6 |
| 3 | 0.1uF | Capacitor_SMD:C_0402_1005Metric | C1, C2, C3 |
| 1 | Conn_01x07 | Connector_PinHeader_2.54mm:PinHeader_1x07_P2.54mm_Vertical | TP1 |
| 1 | GND | FM4DD:Label_GND | G*** |
| 1 | Logo_KiCad_5mm | FM4DD:Logo_KiCad_5mm_SScr | L1 |
| 1 | MX25R6435FZAIL0 | FM4DD:USON-8_4x4mm | U1 |
| 1 | PMOD_02x06 | FM4DD:PMODPinSocket_2x06_P2.54mm_Horizontal | J1 |
| 1 | PMOD_02x06 | FM4DD:PMODHeader_2x06_P2.54mm_Horizontal | J2 |
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Questions
How big is the Flash PCB?
It measures 41 × 20.3 mm and has 2 copper layers, 0.8 mm thick.
What parts does the Flash use?
15 parts, built around the MX25R6435FZAIL0 and CC0402KRX7R7BB104. 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 Flash KiCad files?
From the fm4dd/pmod-flash repository on GitHub, at the commit this page was made from: the board is kicad/flash.kicad_pcb and its schematic kicad/flash.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Flash design in my own project?
Its repository states no licence, so its author keeps all rights: ask fm4dd before reusing the design.