I2C Master Write

This sample code guide is written to help users easily and completely understand I2C sample. This sample demonstrates I2C master write data function in polling mode and GDMA mode. In this sample, I2C is configured as the master. The chip writes some data to I2C slave.

Requirements

For hardware requirements, please refer to the Requirements.

Wiring

Connect P0_0 to the SCL of the I2C slave, connect P0_1 to the SDA of the I2C slave, need to connect 2.2k pull-up resistor.

The hardware connection of I2C sample code is shown in the figure below.

I2C Sample Code Hardware Connection Diagram

Configurations

1. The following macros can be configured to modify pin definitions.

   • #define PIN_I2C1_SCL P0_0

   • #define PIN_I2C1_SDA P0_1

2. The entry function is as follows, call this function in main() to run this sample code. For more details, please refer to the Initialization.

   i2c_mw_demo();
   

Building and Downloading

For building and downloading, please refer to the Building and Downloading.

Experimental Verification

Press the Reset button on the EVB, the master device sends 12 bytes of data to slave, the I2C slave will receive data 0xaa, 0xbb, 0x66, 0x68, 0x77, 0x88, 0xaa, 0xbb, 0x66, 0x68, 0x77, 0x88.

Code Overview

This section introduces the code and process description for initialization and corresponding function implementation in the sample.

Source Code Directory

• For project directory, please refer to Source Code Directory.

• Source code directory: sdk\src\sample\io_demo\i2c\master_write\i2c_mw_demo.c.

Initialization

The initialization flow for peripherals can refer to Initialization Flow.

I2C master mode initialization flow is shown in the following figure.

I2C Master Mode Initialization Flow Chart

1. Call hal_i2c_init_pin() to initialize the pin.

   hal_i2c_init_pin(I2C_ID, PIN_I2C1_SCL, PIN_I2C1_SDA);
   

2. Initialize the I2C peripheral:

   1. Define the T_I2C_MASTER_CONFIG type i2c_config.

   2. Modify the i2c_config parameters as needed. The I2C initialization parameter configuration is shown in the table below.

   3. Call hal_i2c_init_master_mode() to initialize the I2C peripheral.

   I2C Initialization Parameters

   I2C Hardware Parameters	Setting in the i2c_config	I2C
   Clock	T_I2C_MASTER_CONFIG::i2c_speed	400000
   Address Mode (7bits/10bits Mode)	T_I2C_MASTER_CONFIG::addr_mode	T_I2C_ADDR_MODE::I2C_ADDR_MODE_7_BITS
   Slave Address	T_I2C_MASTER_CONFIG::target_slave_addr	0x08
   Lock Type	T_I2C_MASTER_CONFIG::lock_type	T_I2C_LOCK_TYPE::I2C_LOCK_DISABLE

3. Call GDMA_channel_request to request an unused GDMA channel.

4. Call hal_i2c_enable_tx_dma_mode() to initialize the I2C TX GDMA mode.

Functional Implementation

Master Write By Polling Mode

The master call hal_i2c_master_write(), sends the data in I2C_WriteBuf to the slave by polling mode.

uint8_t I2C_WriteBuf[16] = {0xaa, 0xbb, 0x66, 0x68, 0x77, 0x88};

/* Use polling mode to write */
T_I2C_STATUS ret = hal_i2c_master_write(I2C_ID, ADDR, I2C_WriteBuf, 6);

if (ret != I2C_STATUS_OK)
{
   IO_PRINT_ERROR1("i2c_mw_demo: Polling mode send failed %d", ret);
}

Master Write By GDMA Mode

The master call hal_i2c_master_write_by_dma(), sends the data in I2C_WriteBufDMA to the slave by GDMA mode.

uint16_t I2C_WriteBufDMA[16] = {0xaa, 0xbb, 0x66, 0x68, 0x77, 0x88};

/* Use dma mode to write */
ret = hal_i2c_master_write_by_dma(I2C_ID, ADDR, I2C_WriteBufDMA, 6);

if (ret != I2C_STATUS_OK)
{
   IO_PRINT_ERROR1("i2c_mw_demo: DMA mode send failed %d", ret);
}