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IICMB IRQ driver

Interrupt driven dataflow for IICMB.

API

To interact with HDL IICMB can following API used.

Init

Initializes the IICMB driver.

  • *self : common storage handle
  • iicmbAdr: base address pointer to IICMB
  • bus: selected I2C channel
int iicmb_init(t_iicmb *self, void* iicmbAdr, uint8_t bus);

Wait

Waits until IICMB reaches busy state. This would allow to run this driver in a poll loop.

  • *self : common storage handle
int iicmb_busy_wait(t_iicmb *self);

ISR

IICMB fsm. This function needs to be called by the processors Interrupt handler.

  • *self : common storage handle
void iicmb_fsm(t_iicmb *self);

Busy

Checks if the IICMB is ready for new requests.

  • *self : common storage handle
int iicmb_busy(t_iicmb *self);

Error

Checks if the last transfer ended with an error.

  • *self : common storage handle
int iicmb_is_error(t_iicmb *self);

Write

Writes data packet to I2C slave.

  • *self : common storage handle
  • adr7: 7bit slave address
  • *data: pointer to write data
  • len: number of bytes in *data
int iicmb_write(t_iicmb *self, uint8_t adr7, void* data, uint16_t len);

Read

Reads data packet from I2C slave.

  • *self : common storage handle
  • adr7: 7bit slave address
  • *data: pointer to read data
  • len: number of bytes in *data
int iicmb_read(t_iicmb *self, uint8_t adr7, void* data, uint16_t len);

Write-Read

Writes to I2C slave, sends a repeated start condition and starts with read. Read and write data takes place in the same buffer. That means the read data will overwrite the write data.

  • *self : common storage handle
  • adr7: 7bit slave address
  • *data: pointer to read data
  • wrLen: number of write bytes in *data
  • rdLen: number of read bytes to capture in *data
int iicmb_wr_rd(t_iicmb *self, uint8_t adr7, void* data, uint16_t wrLen, uint16_t rdLen);

Example

The code snippet below shows the integration of the driver into a user application.

#include <stdlib.h> // EXIT codes, malloc
#include <stdio.h>  // f.e. printf
#include <stdint.h> // defines fixed data types: int8_t...
#include "iicmb.h"  // IICMB driver

t_iicmb g_iicmb;  // handle for IICMB driver

/**
 *  isr
 *    ISR IICMB Macro
 */
void processors_isr(void)
{
  iicmb_fsm(&g_iicmb);
}

/**
 *  main
 */
int main ()
{
  /* variables */
  uint8_t i2c[10];  // I2C packet to interact

  /* init IICMB
   *   base address 'NULL', change to physical address of IICMB
   *   traffic on I2C channel 0
   */
  iicmb_init(&g_iicmb, (void*) NULL, 0);

  /* issue transfer
   *   access I2C slave with address 0x12
   *   write 5 bytes to slave
   *   read 8 bytes from slave
   */
  iicmb_wr_rd(&g_iicmb, 0x12, &i2c, 5, 8);

  /* wait for transfer */
  while ( iicmb_busy(&g_iicmb) ) {
    __asm("nop");
  }

  /* normal end */
  exit(0);
}

For exemplary compile:

gcc -c -O iicmb.c -o iicmb.o
gcc -c -O main.c -o main.o
gcc iicmb.o main.o -lm -o main

Test

Githubs CI/CD executes the Makefile and performs some simple tests.