RP2040

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The Pico-compatible part of the UDOO KEY is built upon a Raspberry Pi RP2040 microcontroller, dual Arm Cortex-M0+, with a QSPI 8MB Flash, a 133MHz clock and 264KB of on-chip SRAM. The RP2040 microcontroller is a chip from Raspberry Pi Foundation that integrates two Arm Cortex-M0+ CPUs that can be run up to 133MHz, featuring 264kB of on-chip SRAM and up to 16MB of off-chip Flash memory. This microcontroller can be used for machine learning, motor control, audio and so on. The UDOO KEY is 100% compatible with Raspberry Pi Pico both hardware and software-wise. This means that each and any expansion hardware as well as each and any software built for Raspberry Pi Pico will work out of the box on UDOO KEY. For further information on RP2040, please refer to the dedicated page on raspberrypi.com.

P1 and P2 connectors of the Pico part can be used to connect external peripherals to the RP2040. Two 20-pin headers or castellated holes must be soldered on P1 and P2 in a proper manner to use them . The following tables summarize the possibilities offered by P1 and P2 connectors.

P1

Pin number	Schematic pin name	SPI	UART interface	I²C	PWM	SIO/PIO
1	N.C.	-	-	-	-	-
2	N.C.	-	-	-	-	-
3	GND	-	-	-	-	-
4	RPI_SDA	SPI0_SCK	UART0_CTS	I2C1_SDA	PWM1_A	SIO/PIO0/PIO1
5	RPI_SCL	SPI0_TX	UART0_RTS	I2C1_SCL	PWM1_B	SIO/PIO0/PIO1
6	GP4	SPI0_RX	UART1_TX	I2C0_SDA	PWM2_A	SIO/PIO0/PIO1
7	GP5	SPI0_CSn	UART1_RX	I2C0_SCL	PWM2_B	SIO/PIO0/PIO1
8	GND	-	-	-	-	-
9	GP6	SPI0_SCK	UART1_CTS	I2C1_SDA	PWM3_A	SIO/PIO0/PIO1
10	GP7	SPI0_TX	UART1_RTS	I2C1_SCL	PWM3_B	SIO/PIO0/PIO1
11	GP8	SPI1_RX	UART1_TX	I2C0_SDA	PWM4_A	SIO/PIO0/PIO1
12	GP9	SPI1_CSn	UART1_RX	I2C0_SCL	PWM4_B	SIO/PIO0/PIO1
13	GND	-	-	-	-	-
14	GP10	SPI1_SCK	UART1_CTS	I2C1_SDA	PWM5_A	SIO/PIO0/PIO1
15	GP11	SPI1_TX	UART1_RTS	I2C1_SCL	PWM5_B	SIO/PIO0/PIO1
16	GP12	SPI1_RX	UART0_TX	I2C0_SDA	PWM6_A	SIO/PIO0/PIO1
17	GP13	SPI1_CSn	UART0_RX	I2C0_SCL	PWM6_B	SIO/PIO0/PIO1
18	GND	-	-	-	-	-
19	GP14	SPI1_SCK	UART0_CTS	I2C1_SDA	PWM7_A	SIO/PIO0/PIO1
20	GP15	SPI1_TX	UART0_RTS	I2C1_SCL	PWM7_B	SIO/PIO0/PIO1

Pin number 1 and 2 are not connected since are used for MCUs communication.

P2

Pin number	Schematic pin name	SPI	UART interface	I²C	PWM	SIO/PIO
1	GP16	SPI0_RX	UART0_TX	I2C0_SDA	PWM0_A	SIO/PIO0/PIO1
2	GP17	SPI0_CSn	UART0_RX	I2C0_SCL	PWM0_B	SIO/PIO0/PIO1
3	GND	-	-	-	-	-
4	GP18	SPI0_SCK	UART0_CTS	I2C1_SDA	PWM1_A	SIO/PIO0/PIO1
5	GP19	SPI0_TX	UART0_RTS	I2C1_SCL	PWM1_B	SIO/PIO0/PIO1
6	GP20	SPI0_RX	UART1_TX	I2C0_SDA	PWM2_A	SIO/PIO0/PIO1
7	GP21	SPI0_CSn	UART1_RX	I2C0_SCL	PWM2_B	SIO/PIO0/PIO1
8	GND	-	-	-	-	-
9	GP22	SPI0_SCK	UART1_CTS	I2C1_SDA	PWM3_A	SIO/PIO0/PIO1
10	RPI_RESET	-	-	-	-	-
11	GP26	SPI1_SCK	UART1_CTS	I2C1_SDA	PWM5_A	SIO/PIO0/PIO1
12	GP27	SPI1_TX	UART1_RTS	I2C1_SCL	PWM5_B	SIO/PIO0/PIO1
13	GND	-	-	-	-	-
14	GP28	SPI1_RX	UART0_TX	I2C0_SDA	PWM6_A	SIO/PIO0/PIO1
15	ADC_VREF	-	-	-	-	-
16	3V3	-	-	-	-	-
17	N.C.	-	-	-	-	-
18	GND	-	-	-	-	-
19	VSYS	-	-	-	-	-
20	VBUS	-	-	-	-	-

Pin number:

• 10 is reserved for RP2040 reset by ESP32
• 16 provide 3.3V DC (315mA) in output
• 17 is not connected
• 19 provide 5V DC (500mA) filtered from USB Type-C connector (CN1)
• 20 provide 5V DC (500mA) raw from USB Type-C connector (CN1)

P5

The Serial Wire Debug interface is available on the 1x3 poles connector P5. This header allows you to program and debug the RP2040 microcontroller externally.
The following table shows the pin configuration.

Pin number	Function
1	SWCLK
2	GND
3	SWDIO