circuitpython/ports/nrf/boards/sparkfun_nrf52840_micromod/README.md

SparkFun MicroMod nRF52840 Processor

Featuring the nRF52840 SoC from Nordic Semiconductor, the SparkFun MicroMod nRF52840 Processor offers a powerful combination of ARM Cortex-M4 CPU and 2.4 GHz Bluetooth transceiver in the MicroMod form-factor with the M.2 MicroMod connector to allow you to plug in a compatible MicroMod Carrier Board with any number of peripherals.

The MicroMod nRF52840 Processor features the same Raytac MDBT50Q-P1M found on our Pro nRF52840 Mini. This module includes an integrated trace antenna, fits the IC to an FCC-approved footprint along with including decoupling and timing mechanisms that would need to be designed into a circuit using the bare nRF52840 IC. The Bluetooth transceiver included on the nRF52840 boasts a BT 5.1 stack and supports Bluetooth 5, Bluetooth mesh, IEEE 802.15.4 (Zigbee & Thread) and 2.4Ghz RF wireless protocols (including Nordic's proprietary RF protocol) allowing you to pick which option works best for your application.

We've also routed two I²C buses, 2 SPI buses, eleven GPIO, dedicated digital, analog, PWM & PDM pins along with multiple serial UARTS to cover nearly all of your peripheral needs.

CircuitPython Pin Defs

CircuitPython pin definitions, while similar to other boards represent a slight departure from just the typical A and D pin definitions. The majority of general pins are labeled as G (or alternatively, BUS,) as the MicroMod system they build on uses those names to specify pins that may not be specficially analog or digital.

This can be somewhat confusing, especially around the analog pins. Here's a quick pin-map:

MicroMod Pin #	ATP Pin Label	Pin Definition	Additional Definitions	Pin/Port Reference	Notes
8	G11			(Not Connected)
10	D0	D0		P0_27
11	BOOT	BOOT		P0_07
12	SDA	I2C_SDA	SDA	P0_08
13	RTS1	UART_RTS1		P1_02
14	SCL	I2C_SCL	SCL	P0_11
15	CTS1	UART_CTS1		P1_09
16	/I2C INT	I2C_INT		P0_15
17	TX	UART_TX1	TX	P1_03
18	D1	D1		P1_08
19	RX	UART_RX1	RX	P1_10
20	RX2	UART_RX2		P1_05
22	TX2	UART_TX2		P1_07
32	PWM0	PWM0		P0_06
34	A0	A0		P0_04	Attached to AIN2
38	A1	A1		P0_05	Attached to AIN3
40	G0	G0	BUS0	P0_29	Attached to AIN5
42	G1	G1	BUS1	P0_03	Attached to AIN1
44	G2	G2	BUS2	P1_13
46	G3	G3	BUS3	P1_12
47	PWM1	PWM1		P0_16
48	G4	G4	BUS4	P1_11
49	BATT_VIN	BATT_VIN3		P0_30	Attached to AIN6, will be battery voltage / 3.
50	PDM_CLK	PDM_CLK		P0_25
51	SDA1	I2C_SDA1		P1_01
52	PDM_DATA	PDM_DATA		P0_26
53	SCL1	I2C_SCL1		P0_24
55	/CS	SPI_CS		P0_20
57	SCK	SPI_SCK	LED_CLK	P0_28	Attached to AIN4
59	COPI	SPI_COPI	SPI_MOSI, LED_DAT	P0_31	Attached to AIN7
60	SCK1	SDIO_SCK	SPI_SCK1
61	CIPO	SPI_CIPO	SPI_MISO	P0_02
62	COPI1	SDIO_CMD	SPI_COPI1
63	G10	G10		P0_10	Attached to NFC2
64	CIPO1	SDIO_DATA0	SPI_CIPO1
65	G9	G9		P0_09	Attached to NFC1
66	DAT1	SDIO_DATA1
67	G8	G8		P1_14
68	DAT2	SDIO_DATA2
69	G7	G7	BUS7	P1_04
70	CS1	SDIO_DATA3	SPI_CS1
71	G6	G6	BUS6	P1_06
73	G5	G5	BUS5	P0_15

Peripheral Naming

The SparkFun MicroMod spec uses a zero-based peripheral numbering scheme. The 0th peripheral is the default and the "0" is omitted from the peripheral name. For example, the first I2C peripheral is named I2C (instead of I2C0) and the second I2C peripheral is named I2C1. Note: MicroMod UART is not present in the edge connector pinout because the primary debug serial port (i.e.UART0) is exposed as a virtual serial port over USB. As a result, the first UART peripheral in the edge connector pinout is UART1 and the second UART peripheral is UART2.

For more details, see https://www.sparkfun.com/micromod#tech-specs.

Bootloader Notes

The MicroMod nRF52840 Processor needs to have the Adafruit nRF52 UF2 bootloader flashed on it.

Hardware Reference

The MicroMod nRF52840 Processor hardware layout is open source:

• Schematic
• Eagle Files
• Hookup Guide