This is a reference design for the nrF52840 for easy SWD programming and testing. This layout uses the nrF52840 module from Raytek called the MDBT50Q. This PCB has been tested and it works! This design relied heavily on the work of Adafruit’s feather board.

https://github.com/hydronics2/nrF52840_Reference_PCB

Simple SOIC SPI Memory Breakout PCB Labeled both single SPI and QUAD SPI output

128Mb supported by PJRC SPI Library W25Q128JV

This is a simple breakout board for a RDA5807 Radio Module available for less than $1.

The RDA 5807M is single chip broadcast FM stereo Radio tuner with both frequency selection and RDS/RBDS decoder over i2c. The RDA5807M series support FM bands 50MHz to 115MHz.

I’ll be using the arduion IDE to program a microcontroller to use the RDA5807M.

https://github.com/hydronics2/RDA5807M-FM-Radio-Module-Breakout-PCB

Ready for SWD Programming SWDIO is on PA31 SWCLK is on PA30

github for parts https://github.com/hydronics2/samd21_QFP_reference_PCB

This board receives RS485 signals via RJ485 ethernet jack. Converts the two differential pairs back into clock and data SPI signals for one LED panel. The board also has a DC-to-DC converter that takes 45V to 5V to supply to the LED panel.

Trnsceiver Chip: SP485EN, 1016-1829-1-ND RJ45 Ethernet Jack: 380-1316-5-ND DC-DC converter - PYB20-Q48-S5

https://github.com/hydronics2/HDMI-to-FPGA-to-APA102-Pixels https://hackaday.io/project/163657-hdmi-to-fpga-to-apa102