Library Maters PCF857x

The PCF8574/74A/75 are general-purpose I/O expander that connect via the two-wire bidirectional I2C-bus (serial clock (SCL), serial data (SDA)). The Library masters PCF857x is the full-function driver of the SHT4x sensors series (PCF8574, PCF8574A, PCF8575). The driver is written in C language with Code Blocks.

Table of Contents

• Install
• Examples
• Usage
  • example basic
  • example interface
• Document
• How to contribute
• License
• Contact Us
• Acknowledgements

Install

• The interface .C file expects bellow functions to correctly link the driver

  - pcf857x_interface_i2c_init function  ( optional )
  - pcf857x_interface_i2c_deinit function ( optional )
  - pcf857x_interface_i2c_read function ( Mandatory )
  - pcf857x_interface_i2c_write function ( Mandatory )
  - pcf857x_interface_delay_ms function ( Mandatory )
  - pcf857x_interface_debug_print function (optional )

• refer to the video: "Coming soon..."
• Use example project

Examples

• STM32L432 (STM32CubeIDE)
• PIC24FJ128GA705 (MPLAB X IDE)
• SAMD21G18 (Atmel studio 7)

Usage

example basic

#include <atmel_start.h>
#include "pcf857x_driver/pcf857x_driver_basic.h"

void serial_print(const char *pString, uint8_t u8Length);
uint8_t i2c_write(uint8_t addr, uint8_t reg, uint8_t *buf, uint16_t len);
uint8_t i2c_read(uint8_t addr, uint8_t reg, uint8_t *buf, uint16_t len);

/**
* @brief application example state machine
*/
typedef enum
{
  READ_WRITE = 0x00,
  TOGGLE     = 0x01,
  WRITE_ALL  = 0x03

}example_state_t;



int main(void)
{
  /* Initializes MCU, drivers and middleware */
  atmel_start_init();
  
  example_state_t  example_state;
  
  err = pcf857x_basic_initialize(PCF8575_VARIANT,PCF857X_ADDRESS_A001);            /**< i2c pin address (A2, A1, A0) */
   if(err != PCF857X_DRV_OK){
       pcf857x_interface_debug_print("initialize failed, error code: %d\r", err);
   }

   /**< READ ME
    * NOTE THAT PCF8575C VARIANT PINS ARE CURRENT SINK, MEANING ONE CAN NOT WRITE A HIGH AS VDD. PLEASE YOUR DATA SHEET FOR DIFFERENCES BETWEEN PCF8575 VS PCF8575C
    * */

   err = pcf857x_info(&pcf857x_handler);

   pcf857x_interface_debug_print("Chip Name: \t%s\r\n", pcf857x_handler.info.chip_name);
   pcf857x_interface_debug_print("Manufacturer: \t%s\r\n",pcf857x_handler.info.manufacturer_name);
   pcf857x_interface_debug_print("Interface Protocol: \t%s\r\n", pcf857x_handler.info.interface);
   pcf857x_interface_debug_print("Supply Volt Max: \t%.1f V\r\n",pcf857x_handler.info.supply_voltage_max_v);
   pcf857x_interface_debug_print("Supply Volt Min: \t%.1f V\r\n",pcf857x_handler.info.supply_voltage_min_v);
   pcf857x_interface_debug_print("Maximum Current: \t%.1f mA\r\n",pcf857x_handler.info.max_current_ma);
   pcf857x_interface_debug_print("Max Temperature: \t%.1f C\r\n",pcf857x_handler.info.temperature_max);
   pcf857x_interface_debug_print("Diver Version: \t\tV%.1f.%.2d\r\n",(pcf857x_handler.info.driver_version /1000), (uint8_t)(pcf857x_handler.info.driver_version - (uint8_t)(pcf857x_handler.info.driver_version / 100)*100));
   pcf857x_interface_debug_print("\nRecommended min MCU flash: \t%dkB\r\n",pcf857x_handler.info.flash_size_min);
   pcf857x_interface_debug_print("Recommended min MCU RAM: \t%dkB\r\n",pcf857x_handler.info.ram_size_min);

   /**< uncomment one of below options to test the driver */
   //example_state = READ_WRITE;
   example_state = TOGGLE;
   //example_state = WRITE_ALL;

  /* Replace with your application code */
  while (1) {
  	
  	 switch(example_state)
  	 {

  		 case READ_WRITE:
  		 {
  			 if(pcf857x_basic_gpio_read(PCF857X_GPIO_PIN_0) == LOW){           /**< read pin 0 and de-bounce button */
  				 pcf857x_interface_delay_ms(10);
  				 if(pcf857x_basic_gpio_read(PCF857X_GPIO_PIN_0) == LOW)
  				 {
  					 pcf857x_basic_gpio_write(PCF857X_GPIO_PIN_11, HIGH);
  				 }

  				 }else{
  				 pcf857x_basic_gpio_write(PCF857X_GPIO_PIN_11, LOW);
  			 }
  			 break;
  		 }

  		 case TOGGLE:
  		 {
  			 pcf857x_basic_gpio_toggle(PCF857X_GPIO_PIN_7);               /**< toggle pin 7 every 500 ms */
  			 pcf857x_interface_delay_ms(500);
  			 break;
  		 }

  		 case WRITE_ALL:
  		 {
  			 pcf857x_basic_gpio_write_all(HIGH);               /**< Write high on all port */
  			 pcf857x_interface_delay_ms(500);
  			 pcf857x_basic_gpio_write_all(LOW);                /**< low high on all port */
  			 pcf857x_interface_delay_ms(500);
  			 break;
  		 }

  	 }
  }
}


/**
* @brief transmit serial data via usb com port
* @param[in] pTxBuffer point to data to sent
* @param[in] length is the data size
* @return
* @note		none
* */
void serial_print(const char *pString, uint8_t u8Length)
{
  struct io_descriptor *io;
  usart_sync_get_io_descriptor(&USART_0, &io);
  usart_sync_enable(&USART_0);

  io_write(io, (char *)pString, u8Length);
}

/**
* @brief i2c data transmit
* @param[in] addr is the slave address
* @param[in] reg the register to write
* @param[in] buf the data to be written
* @param[in] len size of data
* @return  status code
* 			- 0 success
* 			- 1 failed to write
* @note	none
* */
uint8_t i2c_write(uint8_t addr, uint8_t reg, uint8_t *buf, uint16_t len)
{
  struct io_descriptor *I2C_0_io;

  i2c_m_sync_get_io_descriptor(&I2C_0, &I2C_0_io);
  i2c_m_sync_enable(&I2C_0);
  i2c_m_sync_set_slaveaddr(&I2C_0, addr, I2C_M_SEVEN);
  
  io_write(I2C_0_io, (uint8_t *)buf, len);
  return 0;
}

/**
* @brief i2c data Read
* @param[in] addr is the slave address
* @param[in] reg the register to read
* @param[out] buf point to data to read
* @param[in] len size of data
* @return  status code
* 			- 0 success
* 			- 1 failed to read
* @note	none
* */

uint8_t i2c_read(uint8_t addr, uint8_t reg, uint8_t *buf, uint16_t len)
{
  	struct io_descriptor *I2C_0_io;

  	i2c_m_sync_get_io_descriptor(&I2C_0, &I2C_0_io);
  	i2c_m_sync_enable(&I2C_0);
  	i2c_m_sync_set_slaveaddr(&I2C_0, addr, I2C_M_SEVEN);
  	
  	io_read(I2C_0_io, buf,  len);
  	return 0;
}

example interface

...

/**
* @brief      interface i2c bus read
* @param[in]  u8Addr is the i2c device address 7 bit
* @param[in]  u16Reg is the i2c register address
* @param[out] *pBuf points to a data buffer
* @param[in]  u8length is the length of the data buffer
* @return     status code
*             - 0 success
*             - 1 read failed
* @note       none
*/
uint8_t pcf857x_interface_i2c_read(uint8_t u8Addr, uint16_t u16Reg, uint8_t *pBuf, uint8_t u8Length)
{
  /*call your i2c read function here*/
  /*user code begin */
  if(i2c_read(u8Addr, u16Reg, pBuf, u8Length) !=  0)
  {
  	pcf857x_interface_debug_print("i2c write failed, check the i2c address or wiring\n");
  	return 1;
  }
  /*user code end*/
  return 0; /**< success */
}

/**
* @brief     interface i2c bus write
* @param[in] u8Addr is the i2c device address 7 bit
* @param[in] u16Reg is the i2c register address
* @param[in] *pBuf points to a data buffer
* @param[in] u8length is the length of the data buffer
* @return    status code
*            - 0 success
*            - 1 write failed
* @note      none
*/
uint8_t pcf857x_interface_i2c_write(uint8_t u8Addr, uint16_t u16Reg, uint8_t *pBuf, uint8_t u8Length)
{
  /*call your i2c write function here*/
  /*user code begin */
  if(i2c_write(u8Addr, u16Reg, pBuf, u8Length) !=  0)
  {
  	pcf857x_interface_debug_print("i2c write failed, check the i2c address or wiring\n");
  	return 1;
  }
  /*user code end*/
  return 0; /**< success */
}
...

Document

datasheet

Contribute

1. Clone repo and create a new branch: https://github.com/LibraryMasters/pcf857x_PR
2. Make changes and test
3. Submit a Pull Request with a comprehensive description of changes

License

MIT

Contact Us

Email address: cedricmalyam@gmail.com

Acknowledgements

• @PeterHenderson https://dribbble.com/peterhenderson for the logo