[参考译文] TM4C1294KCPDT：TM4C1294 EVK

//============================================================================
// Name        : i2cAPI.c
// Author      :
// Version     :
// Copyright   : Your copyright notice
// Description : Tiva i2c in C++, Ansi-style
//============================================================================
/*
 * i2cAPI.c
 * Implementation of a i2c interface
 *
 * Copyright
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED ''AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL I
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
 * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */


#include <stdint.h>
#include <stdio.h>
#include <stdbool.h>
#include "i2cAPI.h"
#include "driverlib/inc/tm4c1294kcpdt.h"
#include "driverlib/inc/hw_i2c.h"
#include "driverlib/inc/hw_memmap.h"
#include "driverlib/inc/hw_types.h"
#include "driverlib/inc/hw_gpio.h"
#include "driverlib/i2c.h"
#include "driverlib/sysctl.h"
#include "driverlib/gpio.h"
#include "driverlib/pin_map.h"
#include "driverlib/rom_map.h"
#include "utils/uartstdio.h"

uint32_t i2c_init(uint32_t g_ui32SysClock)
{
	//This function is for eewiki and is to be updated to handle any port
    //  Enable peripherals in use. Also reset I2C2 at the end to allow calling
        //  this function at any point in order to reset I2C interface.
        MAP_SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOD);

        MAP_SysCtlPeripheralEnable(SYSCTL_PERIPH_I2C8);


        // Enable I2C communication interface, SCL, SDA lines
        MAP_GPIOPinConfigure(GPIO_PD2_I2C8SCL);
        MAP_GPIOPinConfigure(GPIO_PD3_I2C8SDA);

        MAP_GPIOPinTypeI2CSCL(GPIO_PORTD_BASE, GPIO_PIN_2);
        MAP_GPIOPinTypeI2C(GPIO_PORTD_BASE, GPIO_PIN_3);

        //  Enable I2C master interface
        MAP_I2CMasterEnable(I2C8_BASE);

        // Run I2C bus in high-speed mode, 400kHz speed
        MAP_I2CMasterInitExpClk(I2C8_BASE, g_ui32SysClock, true);




	/*//enable GPIO peripheral that contains I2C
	SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOD);

	while(!SysCtlPeripheralReady(SYSCTL_PERIPH_GPIOD))
    {
        UARTprintf("I2c master busy Init\r\n");
        break;
    }

	// Configure the pin muxing for I2C0 functions on port B2 and B3.
	GPIOPinConfigure(GPIO_PD2_I2C8SCL);
	GPIOPinConfigure(GPIO_PD3_I2C8SDA);

	// Select the I2C function for these pins.
	GPIOPinTypeI2CSCL(GPIO_PORTD_BASE, GPIO_PIN_2);
	GPIOPinTypeI2C(GPIO_PORTD_BASE, GPIO_PIN_3);
	//I2CMasterEnable( I2C8_BASE );
	// Enable and initialize the I2C0 master module.  Use the system clock for
	// the I2C0 module.  The last parameter sets the I2C data transfer rate.
	// If false the data rate is set to 100kbps and if true the data rate will
	// be set to 400kbps.
	//I2CMasterInitExpClk(I2C8_BASE, SysCtlClockGet(), false);
	SysCtlPeripheralDisable(SYSCTL_PERIPH_I2C8);
	SysCtlPeripheralReset(SYSCTL_PERIPH_I2C8);
	SysCtlPeripheralEnable(SYSCTL_PERIPH_I2C8);

	while(!SysCtlPeripheralReady(SYSCTL_PERIPH_GPIOD))
    {
        UARTprintf("I2c master busy Init_1\r\n");
        break;
    }

	I2CMasterInitExpClk(I2C8_BASE, g_ui32SysClock, true);
*/

	//clear I2C FIFOs
	/*HWREG(I2C8_BASE + I2C_O_FIFOCTL) = 80008000;*/
}

void i2c_read_byte(uint16_t device_address, uint16_t device_register, uint8_t *pui32DataRx)
{
    i2c_read_multi(device_address,device_register,pui32DataRx,1);
}

void i2c_write_byte(uint16_t device_address, uint16_t device_register, uint8_t pui32DataTx)
{
    uint8_t ui8DataTx = pui32DataTx;
    i2c_write_multi(device_address,device_register,&ui8DataTx,1);
}

void i2c_read_multi(uint16_t device_address, uint16_t device_register, uint8_t *pui32DataRx,uint8_t nNumbytes)
{
    uint32_t I2cbaseregAddr = I2C0_BASE;
	//specify that we want to communicate to device address with an intended write to bus
	I2CMasterSlaveAddrSet(I2cbaseregAddr, device_address, false);

	//the register to be read
	I2CMasterDataPut(I2cbaseregAddr, device_register);

	//send control byte and register address byte to slave device
	I2CMasterControl(I2cbaseregAddr, I2C_MASTER_CMD_SINGLE_SEND);

	//wait for MCU to complete send transaction
	while(I2CMasterBusy(I2cbaseregAddr))
    {
	    UARTprintf("I2c master busy\r\n");
    }

	//read from the specified slave device
	I2CMasterSlaveAddrSet(I2cbaseregAddr, device_address, true);

	//send control byte and read from the register from the MCU
	I2CMasterControl(I2cbaseregAddr, I2C_MASTER_CMD_SINGLE_RECEIVE);

	//wait while checking for MCU to complete the transaction
	while(I2CMasterBusy(I2cbaseregAddr))
	{
	    UARTprintf("I2c master busy\r\n");
	}


    // Dummy acknowledge and wait for the receive request from the master.
    // This is done to clear any flags that should not be set.
    //
    while(!(I2CSlaveStatus(I2cbaseregAddr) & I2C_SLAVE_ACT_TREQ))
    {
    }

	if(nNumbytes == 1)
	{
	    pui32DataRx[nNumbytes] = I2CMasterDataGet(I2cbaseregAddr);
	}
	else if(nNumbytes > 1)
	{
	    for(ui32Index = 0; ui32Index < nNumbytes; ui32Index++)
        {
            //
            // Read the data from the master.
            //
            pui32DataRx[ui32Index] = I2CMasterDataGet(I2cbaseregAddr);

            //
            // Display the data that the slave has received.
            //
            //UARTprintf("Received: '%c'\n", pui32DataRx[ui32Index]);
        }

	}
}

void i2c_write_multi(uint16_t device_address, uint16_t device_register, uint8_t* pui32DataTx,uint8_t nNumbytes)  //uint32_t pui32DataTx[NUM_I2C_DATA];
{
    uint32_t I2cbaseregAddr = I2C0_BASE;
	//specify that we want to communicate to device address with an intended write to bus
	I2CMasterSlaveAddrSet(I2cbaseregAddr, device_address, false);

	//register to be read
	I2CMasterDataPut(I2cbaseregAddr, device_register);

	//send control byte and register address byte to slave device
	I2CMasterControl(I2cbaseregAddr, I2C_MASTER_CMD_BURST_SEND_START);

	//wait for MCU to finish transaction
	while(I2CMasterBusy(I2cbaseregAddr));

	I2CMasterSlaveAddrSet(I2cbaseregAddr, device_address, true);

	//specify data to be written to the above mentioned device_register
	while(nNumbytes--)
	{
        //
        // Place the data to be sent in the data register
        //
	    I2CMasterDataPut(I2cbaseregAddr, pui32DataTx);
	    UARTprintf("  Sending: '%c'  . . .  ", pui32DataTx);
        //
        // Initiate send of data from the master.  Since the loopback
        // mode is enabled, the master and slave units are connected
        // allowing us to receive the same data that we sent out.
        //
	    I2CMasterControl(I2cbaseregAddr, I2C_MASTER_CMD_SINGLE_SEND);

	    //
	    // Wait until the slave has received and acknowledged the data.
	    //
	    while(!(I2CSlaveStatus(I2cbaseregAddr) & I2C_SLAVE_ACT_RREQ))
        {
	       UARTprintf("I2c NACK\r\n");
        }

	    pui32DataTx++;
	}
	//wait while checking for MCU to complete the transaction
	I2CMasterControl(I2cbaseregAddr, I2C_MASTER_CMD_BURST_RECEIVE_FINISH);

	//wait for MCU & device to complete transaction
	while(I2CMasterBusy(I2cbaseregAddr));
	{
	    UARTprintf("I2c master busy\r\n");
	}

}