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I2C Module API Manual

Overview

The K230 chip is equipped with 5 I2C hardware modules internally, supporting standard 100 kb/s, fast 400 kb/s, and high-speed 3.4 Mb/s communication modes. In addition, K230 also implements 5 software I2C modules for users to choose from.

Master Device API Introduction

The I2C class is located in the machine module.

Example Code

import time
from machine import I2C

# C32 parameters
EEPROM_ADDR = 0x50  # I2C address of 24C32
PAGE_SIZE = 32      # Page size of 24C32 (bytes)
MEM_SIZE = 4096     # Total capacity of 24C32 (4KB)

# Initialize I2C
i2c = I2C(2, scl=11, sda=12, freq=40000)

def test_24c32():
    print("24C32 EEPROM test started...")

    # Test data - generate cyclic pattern of 0x00-0xFF
    test_data = bytearray([x & 0xFF for x in range(PAGE_SIZE)])
    test_addr = 0x0000  # Test starting address

    print("Write data: [{}]".format(", ".join("0x{:02x}".format(x) for x in test_data)))

    # Write a page of data (24C32 supports page write)
    i2c.writeto_mem(EEPROM_ADDR, test_addr, test_data, addrsize=16)
    print("Write completed, address: 0x{:04x}".format(test_addr))

    # Wait for EEPROM to complete write (important!)
    time.sleep_ms(10)  # 24C32 page write typical time is 5ms

    # Read back data
    read_data = i2c.readfrom_mem(EEPROM_ADDR, test_addr, len(test_data), addrsize=16)
    print("Read data: [{}]".format(", ".join("0x{:02x}".format(x) for x in read_data)))

    # Verify data
    if test_data == read_data:
        print("Test successful! Write and read data match")
    else:
        print("Test failed! Data mismatch")

    # Random address read/write test
    print("\nRandom address read/write test...")
    import urandom
    test_addr = urandom.getrandbits(12)  # Generate 12-bit random address (0-0xFFF)
    test_byte = urandom.getrandbits(8)   # Generate random test byte

    print("Write byte at address 0x{:04x}: 0x{:02x}".format(test_addr, test_byte))
    i2c.writeto_mem(EEPROM_ADDR, test_addr, bytearray([test_byte]), addrsize=16)
    time.sleep_ms(5)  # Wait for write to complete

    read_byte = i2c.readfrom_mem(EEPROM_ADDR, test_addr, 1, addrsize=16)[0]
    print("Read byte: 0x{:02x}".format(read_byte))

    if test_byte == read_byte:
        print("Random address test successful!")
    else:
        print("Random address test failed!")

# Run test
test_24c32()

Constructor

i2c = I2C(id, scl , sda, freq=400000, timeout = 50000)

Parameters

• id: I2C device ID, hardware I2C is [0~4], software I2C is [5~9]

• scl: I2C scl pin

• sda: I2C sda pin

• freq: I2C clock frequency. Software I2C may not be able to set all frequencies, please refer to the actual result.

• timeout: I2C communication timeout

scan Method

i2c.scan()

Scans the slave devices on the current I2C bus and returns a list of 7-bit addresses of responding devices.

Parameters

None

Return Value

Returns a list containing all scanned slave addresses.

readfrom Method

i2c.readfrom(addr, len, True)

Reads data of the specified length from the slave at the specified I2C address.

Parameters

• addr: Slave address.

• len: Length of data to read.

• stop: Whether to send a stop signal. Currently only the default value True is supported.

Return Value

Returns the read data, type is bytes.

readfrom_into Method

i2c.readfrom_into(addr, buf, True)

Reads data from the slave at the specified I2C address into the buffer according to the buffer length.

Parameters

• addr: Slave address.

• buf: bytearray type, defines the length and is used to store the read data.

• stop: Whether to send a stop signal. Currently only the default value True is supported.

Return Value

None

writeto Method

i2c.writeto(addr, buf, True)

Sends the data in the buffer to the slave at the specified I2C address.

Parameters

• addr: Slave address.

• buf: Data to be sent.

• stop: Whether to send a stop signal. Currently only the default value True is supported.

Return Value

Number of bytes successfully sent.

readfrom_mem Method

i2c.readfrom_mem(addr, memaddr, nbytes, addrsize=8)

Reads data of the specified length from the specified memory address of the memory. Used for I2C operations on memory-type devices.

Parameters

• addr: I2C slave address.

• memaddr: Memory storage address.

• nbytes: Number of bytes to read.

• addrsize: Memory address width, default is 8 bits.

Return Value

Returns the read data, type is bytes.

readfrom_mem_into Method

i2c.readfrom_mem_into(addr, memaddr, buf, addrsize=8)

Reads data from the specified memory address of the memory into the buffer according to the buffer length. Used for I2C operations on memory-type devices.

Parameters

• addr: I2C slave address.

• memaddr: Memory storage address.

• buf: bytearray type, defines the length and is used to store the read data.

• addrsize: Register address width, default is 8 bits.

Return Value

None

writeto_mem Method

i2c.writeto_mem(addr, memaddr, buf, mem_size=8)

Writes the data in the specified buffer to the specified memory address of the memory. Used for I2C operations on memory-type devices.

Parameters

• addr: I2C slave address.

• memaddr: Memory storage address.

• buf: Data to be written.

• mem_size: Storage address width, default is 8 bits.

Return Value

None