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Generic I2C GPIO Expander Driver (MCP23017, MCP23008, PCF8574, TCA9555).

  • #include "syn_ioexp.h"
  • #include "../util/syn_assert.h"
  • #include <string.h>

Public Functions

Type Name
SYN_Status syn_ioexp_init (SYN_IOExp * ioexp, SYN_GPIO_Pin scl, SYN_GPIO_Pin sda, uint8_t i2c_addr, SYN_IOExpType type)
Initialize an I2C GPIO Expander instance.
SYN_GPIO_State syn_ioexp_read_pin (SYN_IOExp * ioexp, uint8_t pin)
Read digital input state from a pin.
uint16_t syn_ioexp_read_port (SYN_IOExp * ioexp)
Read entire 16-bit input port mask.
void syn_ioexp_set_pin_mode (SYN_IOExp * ioexp, uint8_t pin, SYN_GPIO_Mode mode)
Set pin mode (input vs output).
void syn_ioexp_write_pin (SYN_IOExp * ioexp, uint8_t pin, SYN_GPIO_State state)
Write digital output state to a pin.
void syn_ioexp_write_port (SYN_IOExp * ioexp, uint16_t mask)
Write entire 16-bit output port mask.

Public Static Functions

Type Name
void write_i2c_bytes (SYN_SoftI2C * i2c, uint8_t dev_addr, const uint8_t * buf, size_t len)

Public Functions Documentation

function syn_ioexp_init

Initialize an I2C GPIO Expander instance. 

SYN_Status syn_ioexp_init (
    SYN_IOExp * ioexp,
    SYN_GPIO_Pin scl,
    SYN_GPIO_Pin sda,
    uint8_t i2c_addr,
    SYN_IOExpType type
)

Parameters:

  • ioexp Expander context.
  • scl I2C SCL pin.
  • sda I2C SDA pin.
  • i2c_addr I2C slave address (e.g. 0x20 or 0x27).
  • type Expander IC type (MCP23017, MCP23008, PCF8574, TCA9555).

Returns:

SYN_OK on success.

function syn_ioexp_read_pin

Read digital input state from a pin. 

SYN_GPIO_State syn_ioexp_read_pin (
    SYN_IOExp * ioexp,
    uint8_t pin
)

Parameters:

  • ioexp Expander context.
  • pin Pin index (0 to num_pins-1).

Returns:

SYN_GPIO_HIGH or SYN_GPIO_LOW.

function syn_ioexp_read_port

Read entire 16-bit input port mask. 

uint16_t syn_ioexp_read_port (
    SYN_IOExp * ioexp
)

Parameters:

  • ioexp Expander context.

Returns:

16-bit port value.

function syn_ioexp_set_pin_mode

Set pin mode (input vs output). 

void syn_ioexp_set_pin_mode (
    SYN_IOExp * ioexp,
    uint8_t pin,
    SYN_GPIO_Mode mode
)

Parameters:

  • ioexp Expander context.
  • pin Pin index (0 to num_pins-1).
  • mode Mode (SYN_GPIO_INPUT, SYN_GPIO_OUTPUT, SYN_GPIO_INPUT_PULLUP).

function syn_ioexp_write_pin

Write digital output state to a pin. 

void syn_ioexp_write_pin (
    SYN_IOExp * ioexp,
    uint8_t pin,
    SYN_GPIO_State state
)

Parameters:

  • ioexp Expander context.
  • pin Pin index (0 to num_pins-1).
  • state State (SYN_GPIO_HIGH or SYN_GPIO_LOW).

function syn_ioexp_write_port

Write entire 16-bit output port mask. 

void syn_ioexp_write_port (
    SYN_IOExp * ioexp,
    uint16_t mask
)

Parameters:

  • ioexp Expander context.
  • mask 16-bit port value.

Public Static Functions Documentation

function write_i2c_bytes

static void write_i2c_bytes (
    SYN_SoftI2C * i2c,
    uint8_t dev_addr,
    const uint8_t * buf,
    size_t len
)

The documentation for this class was generated from the following file src/syntropic/drivers/syn_ioexp.c