3.7 mikroBUS™ Socket (J4)

A mikroBUS™ socket (J4) expands the functionality of the PIC32WM-BW1 Curiosity Board using the MikroElektronika Click adapter boards.

The mikroBUS connector consists of the following:

Pair of 1x8 female headers with proprietary pin configuration and silkscreen markings
The pinout consists of three groups of communications pins:
- Serial Peripheral Interface (SPI)
- Universal Asynchronous Receiver/Transmitter (UART)
- Inter-Integrated Circuit (I²C)
Two power groups
- 3.3V, GND power line
- 5V, GND power line
Four additional pins
- Pulse-Width Modulation (PWM)
- Reset Pin (RST)
- Interrupt
- Analog

Note: For a complete listing of the Click boards, refer to www.mikroe.com/click.

The GPIO pins for the mikroBUS sockets are assigned to route I²C, SPI peripherals and other GPIO pins as follows.

Table 3-6. mikroBUS™ Socket (J4) Pinout Details
Pin Number	Pin Name	Pin on PIC32WM-BW1 Module	Description
1	AN	PB6, AN	ADC analog input
2	RST	PA3	General-purpose I/O pin
3	CS	PA0, SERCOM2_PAD2	Client select pin for SPI (or) General-purpose I/O pin
4	SCK	PA10, SERCOM2_PAD1	SPI clock
5	MISO	PA1, SERCOM2_PAD3	SPI host input client output
6	MOSI	PA9, SERCOM2_PAD0	SPI host output client input
7	+3.3V	+3.3V	3.3V power
8	GND	GND	Ground
9	GND	GND	Ground
10	+5V	NA	5V input power for Click board
11	SDA	PA7, SERCOM1_PAD0	I²C data
12	SCL	PA8, SERCOM1_PAD1	I²C clock
13	TX	PA9, SERCOM3_PAD0	UART TX
14	RX	PA10, SERCOM3_PAD3	UART RX
15	INT	PA2⁽¹⁾	Interrupt pin (or) GPIO pin
16	PWM	PA2⁽¹⁾	PWM pin (or) GPIO pin
Note: The INT and PWM signals are multiplexed on pin PA2, with R120 for PWM and R121 for INT. If conflicts occur during INT or PWM operation, removing R120 or R121 isolates the two functions. The SPI and UART functions share the same GPIO pins, and both cannot operate simultaneously. The UART_TX and SPI_MOSI signals are multiplexed on pin PA9. Pull-up resistors R191 and R111 support the UART_TX functionality. If conflicts occur during SPI operation, removing R191 and R111 isolates the two functions.