Peripherals

[中文]

UART

I2C

I2C driver has been redesigned (see I2C API Reference), which aims to unify the interface and extend the usage of I2C peripheral. Although it is recommended to use the new driver APIs, the legacy driver is still available in the previous include path driver/i2c.h.

The major breaking changes in concept and usage are listed as follows:

Major Changes in Concepts

  • i2c_config_t which was used to configure the I2C bus, but it doesn't really tell whether to configure master or slave. So in the new design, master and slave initialization are separate, user can call i2c_master_bus_config_t or i2c_slave_config_t.

  • i2c_mode_t which was used to tell whether I2C controller works in slave mode or master mode. This enumerator has been deprecated. In the new driver, users don'tneed to manually set the mode anymore since master and slave APIs are different.

  • i2c_rw_t which was used to tell whether I2C master controller is performing a write or a read operation. This is now deprecated.

  • i2c_addr_mode_t was renamed to i2c_addr_bit_len_t.

  • In the legacy driver, operations needed to be chained with a command list (dynamically or statically created). The new driver now handles this internally, making the operations more size and space efficient.

  • Capability flags like I2C_SCLK_SRC_FLAG_FOR_NOMAL are used to select clock source in the legacy driver. In the new driver, users can select clock source directly.

Major Changes in Usage

  • I2C bus initialization is done in two parts: first, initialization of the bus with i2c_new_master_bus(), then, initialization of the I2C device with i2c_master_bus_add_device().

  • i2c_reset_tx_fifo and i2c_reset_rx_fifo have been removed, since it is never required to reset the fifo by users. Whole bus can still be reset by calling i2c_master_bus_reset.

  • i2c_cmd_link_xxx functions have been removed, user doesn't need to use link to link commands on its own.

  • i2c_master_write_to_device has been renamed to i2c_master_transmit.

  • i2c_master_read_from_device has been renamed to i2c_master_receive.

  • i2c_master_write_read_device has been renamed to i2c_master_transmit_receive

  • i2c_slave_write_buffer has been renamed to i2c_slave_transmit

  • i2c_slave_read_buffer has been renamed to i2c_slave_receive

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