Raspberry Pi Code Example

This example (ISXMPL3750ex3) demonstrates how to use the IS3750 Addressable LED Controller chip with an Arduino microcontroller board using the Arduino functions.

You can find the complete example at: www.inacks.com/isxmpl3750ex3

You can get the IS3750 evaluation board (Kappa3750Ard) compatible with Arduino UNO form factor boards at: www.inacks.com/kappa3750rasp

from smbus2 import SMBus, i2c_msg
import time

I2C_BUS = 1  # Use 1 for most Raspberry Pi models
DEVICE_ADDRESS = 0x12  # 7-bit I2C address of the IS3750

# IS3750 register map
REGISTER_SHOW = 0x00
REGISTER_LED1_RED = 0x01
REGISTER_LED1_GREEN = 0x02
REGISTER_LED1_BLUE = 0x03
REGISTER_LED2_RED = 0x04
REGISTER_LED2_GREEN = 0x05
REGISTER_LED2_BLUE = 0x06
REGISTER_LED3_RED = 0x07
REGISTER_LED3_GREEN = 0x08
REGISTER_LED3_BLUE = 0x09

def write_register(start_register, data_bytes):
    """
    Write a block of data starting at a 16-bit register address.
    
    :param start_register: The 16-bit register address to start writing to.
    :param data_bytes: A list of bytes to write.
    """
    high_addr = (start_register >> 8) & 0xFF
    low_addr = start_register & 0xFF
    with SMBus(I2C_BUS) as bus:
        msg = i2c_msg.write(DEVICE_ADDRESS, [high_addr, low_addr] + data_bytes)
        bus.i2c_rdwr(msg)

def show_leds():
    """Send the 'show' command to apply the LED updates."""
    write_register(REGISTER_SHOW, [1])

def clear_all_led_registers():
    """Clear all LED registers by sending 3600 zero bytes."""
    data = [0] * (1200 * 3)
    write_register(REGISTER_LED1_RED, data)

# Example usage loop
while True:
    clear_all_led_registers()
    write_register(REGISTER_LED1_GREEN, [5])
    show_leds()
    time.sleep(1)

    clear_all_led_registers()
    write_register(REGISTER_LED2_RED, [5])
    write_register(REGISTER_LED2_GREEN, [5])
    show_leds()
    time.sleep(1)

    clear_all_led_registers()
    write_register(REGISTER_LED3_RED, [5])
    show_leds()
    time.sleep(1)