Hardware Introduction

The Robot Hat V4 features 2 lithium battery charging, 5V/3A DC-DC discharge, I2S audio output and speaker, a simple battery level indicator, microcontroller-based PWM and ADC drivers, as well as motor drivers.

Pinout

_images/robot_hat_pinout.png
Power Port

  • 7-12V PH2.0 3pin power input.

  • Powering the Raspberry Pi and Robot HAT at the same time.

Power Switch

  • Turn on/off the power of the robot HAT.

  • When you connect power to the power port, the Raspberry Pi will boot up. However, you will need to switch the power switch to ON to enable Robot HAT.

Type-C USB Port

  • Insert the Type-C cable to charge the battery.

  • At the same time, the charging indicator lights up in red color.

  • When the battery is fully charged, the charging indicator turns off.

  • If the USB cable is still plugged in about 4 hours after it is fully charged, the charging indicator will blink to prompt.

Digital Pin
ADC Pin
PWM Pin
Left/Right Motor Port

  • 2-channel XH2.54 motor ports.

  • Pin: Motor Port.

  • API: module motor, 1 for left motor port, 2 for right motor port.

I2C Pin and I2C Port

  • I2C Pin: P2.54 4-pin interface.

  • I2C Port: SH1.0 4-pin interface, which is compatible with QWIIC and STEMMA QT.

  • These I2C interfaces are connected to the Raspberry Pi’s I2C interface via GPIO2 (SDA) and GPIO3 (SCL).

  • Pin: I2C.

  • API: class I2C.

SPI Pin

  • P2.54 7-pin SPI interface.

  • Pin: SPI.

UART Pin

  • P2.54 4-pin interface.

  • Pin: UART.

RST Button

  • The RST button, when using Ezblock, serves as a button to restart the Ezblock program.

  • If not using Ezblock, the RST button does not have a predefined function and can be fully customized according to your needs.

  • Pin: Buttons.

  • API: class Pin

USR Button

  • The functions of USR Button can be set by your programming. (Pressing down leads to a input “0”; releasing produces a input “1”. )

  • API: class Pin, you can use Pin("SW") to define it.

  • Pin: Buttons.

Battery Indicator

  • Two LEDs light up when the voltage is higher than 7.6V.

  • One LED lights up in the 7.15V to 7.6V range.

  • Below 7.15V, both LEDs turn off.

  • Battery Level Indicator.

Speaker and Speaker Port

  • Speaker: This is a 2030 audio chamber speaker.

  • Speaker Port: The Robot HAT is equipped with onboard I2S audio output, along with a 2030 audio chamber speaker, providing a mono sound output.

  • Pin: Speaker and Speaker Port.

  • API: class Music

Pin Mapping

Raspberry Pi IO

Robot Hat V4

Raspberry Pi

Robot Hat V4

Raspberry Pi

NC

3V3

5V

5V

SDA

SDA

5V

5V

SCL

SCL

GND

GND

D1

GPIO4

TXD

TXD

GND

GND

RXD

RXD

D0

GPIO17

I2S BCLK

GPIO18

D2

GPIO27

GND

GND

D3

GPIO22

MOTOR 1 DIR

GPIO23

NC

3V3

MOTOR 2 DIR

GPIO24

SPI MOSI

MOSI

GND

GND

SPI MISO

MISO

USR BUTTON

GPIO25

SPI SCLK

SCLK

SPI CE0

CE0

GND

GND

NC

CE1

NC

ID_SD

NC

ID_SC

MCU Reset

GPIO5

GND

GND

(SPI)BSY

GPIO6

Board Identifier 2

GPIO12

Board Identifier 1

GPIO13

GND

GND

I2S LRCLK

GPIO19

RST BUTTON

GPIO16

USER LED

GPIO26

NC

GPIO20

GND

GND

I2S SDATA

GPIO21

Digital IO

Robot HAT has 4 sets of 3Pin digital pins.

_images/digitalio.png
Digital IO

Robot Hat V4

Raspberry Pi

D0

GPIO17

D1

GPIO4

D2

GPIO27

D3

GPIO22

ADC

_images/adcpin.png

The Robot HAT features four sets of 3Pin ADC (Analog to Digital Converter) pins, each spaced 2.54mm apart. These pins operate at a 3.3V power supply. The ADC function, offering 12-bit precision, is facilitated by an onboard microcontroller. Detailed instructions for reading ADC values are provided in the On-Board MCU section.

_images/btradc.png

Also, ADC channel A4 is connected to the battery through a voltage divider using resistors, which will be used to measure the battery voltage to estimate the approximate battery charge.

The voltage divider ratio is 20K/10K, so:

  • A4 voltage (Va4) = value_A4 / 4095.0 * 3.3

  • Battery voltage (Vbat) = Va4*3

  • Battery voltage (Vbat) = value_A4 / 4095.0 * 3.3 * 3

PWM

_images/pwmpin.png

Robot HAT has 4 sets of 3Pin PWM pins, each spaced 2.54mm apart, and the power supply is 5V. The method of using the PWM is described in detail in On-Board MCU.

Note

PWM13 & 14 channels are used for motor drive.

I2C

_images/i2cpin.png

The Robot HAT has two I2C interfaces. One is the P2.54 4-pin interface, and the other is the SH1.0 4-pin interface, which is compatible with QWIIC and STEMMA QT. These I2C interfaces are connected to the Raspberry Pi’s I2C interface via GPIO2 (SDA) and GPIO3 (SCL). The board also features an On-Board MCU, and the two signal lines have 10K pull-up resistors.

SPI

_images/spipin.png

The SPI interface of the Robot HAT is a 7-pin P2.54 interface. It connects to the SPI interface of the Raspberry Pi and includes an additional I/O pin that can be used for purposes such as interrupts or resets.

SPI

Robot Hat V4

Raspberry Pi

BSY

GPIO6

CS

CE0(GPIO8)

SCK

SCLK(GPIO11)

MI

MISO(GPIO9)

MO

MOSI(GPIO10)

3V3

3.3V Power

GND

Ground

UART

_images/uartpin.png

The UART interface of the Robot HAT is a 4-pin P2.54 interface. It connects to the Raspberry Pi’s GPIO14 (TXD) and GPIO15 (RXD) pins.

Buttons

The Robot HAT comes with 1 LED and 2 buttons, all directly connected to the Raspberry Pi’s GPIO pins. The RST button, when using Ezblock, serves as a button to restart the Ezblock program. If not using Ezblock, the RST button does not have a predefined function and can be fully customized according to your needs.

LED & Button

Robot Hat V4

Raspberry Pi

LED

GPIO26

USR

GPIO25

RST

GPIO16

Speaker and Speaker Port

The Robot HAT is equipped with onboard I2S audio output, along with a 2030 audio chamber speaker, providing a mono sound output.

I2S

I2S

Raspberry Pi

LRCLK

GPIO19

BCLK

GPIO18

SDATA

GPIO21

Motor Port

The motor driver of the Robot HAT supports 2 channels and can be controlled using 2 digital signals for direction and 2 PWM signals for speed control.

Motor Driver

Motor

IO

Motor1 Dir

GPIO23

Motor1 Power

PWM13

Motor2 Dir

GPIO24

Motor2 Power

PWM12

Battery Level Indicator

The battery level indicator on the Robot HAT monitors the battery voltage using a voltage divider method and serves as a reference for estimating the battery level. The relationship between the LED and voltage is as follows:

Battery Level

LED Battery

Total Voltage

2 LEDs on

Greater than 7.6V

1 LED on

Greater than 7.15V

Both LEDs off

Less than 7.15V

When any one of the batteries reaches or exceeds 4.1V while the others are below that threshold, the charging current of that specific battery will be reduced.