Pico-HAT: Connect your Raspi with the Pico through I²C

All infos on: http://www.weigu.lu/microcontroller/pico_hat/index.html

Some infos

The Pico connects to all the sensors and actuators and can act in Real Time. The Raspi can do the rest (Wifi, Webserver, MQTT, Display ...). The Pico is an I²C slave to the Raspi and the Raspi sends commands with a Python script to the Pico. An Arduino program on the Pico answers with sensor data or by switching an actuator.

As the Arduino IDE runs on a Raspi, both device (Raspi and Pico) can be reprogrammed via VNC from any computer, and I find this pretty amazing :).

Features

• The Raspi is connected through I²C with the Pico. Serial is prepared if needed (by adding 2 0 Ω resistors).

• The Pico can be powered over USB (recommended if you want to reprogram it via Arduino IDE and VNC) or through the Raspi (5 V).

• All GPIOs have the possibility to add a voltage divider to reduce the input voltage (e.g. 5 V to 3.3 V), or to add an external pull-down resistor.

• All headers have beneath a ground pin, one or two power pins (3.3 V or 5 V; H2 headers: 3.3 V and 5 V).

• Additionally we get a RESET-button, an SWD header, 2 power header (3.3 V and 5 V), 2 Ground pins, an an 3V3_EN and ADC_VREF pins.

Circuit

The circuit is designed with KiCAD and is open hardware. The following headers are available:

Name	Pin 1	Pin 2	Pin 3	Pin 5	Pin 5	Pin 6	Pin 7
5V_Pico	GND	5 V
3V3_Pico	GND	3.3 V
SWD	SWDIO	GND	SWCLK
H1_ADC0	GND	ADC0 (GPIO26)	3.3 V
H2_ADC1	GND	ADC1 (GPIO27)	3.3 V
H3_ADC2	GND	ADC2 (GPIO28)	3.3 V
H1x1	GND	GPIO22	3.3 V (or 5 V)
H3x1	GND	GPIO13	3.3 V (or 5 V)
H4x1	GND	GPIO12	3.3 V (or 5 V)
H2x1	GND	GPIO12	3.3 V	5 V
H1x2	GND	GPIO17 (alt. RX0-TX_Raspi)	GPIO16 (alt. TX0-RX_Raspi)	3.3 V (or 5 V)
H3x2	GND	GPIO10	GPIO11	3.3 V (or 5 V)
H4x2	GND	GPIO6	GPIO7	3.3 V (or 5 V)
H2x2	GND	GPIO8	GPIO9	3.3 V	5 V
H1x4	GND	GPIO21	GPIO20	GPIO19	GPIO18	3.3 V (or 5 V)
H2x4	GND	GPIO2	GPIO3	GPIO4	GPIO5	3.3 V	5 V