I2C interface on Tiva
11,837
Solution 1
The problem has been resolved. There were issues:
- It is essential to populate external pull ups.
- Use
GPIOPinTypeI2C()2nd parameter as a bit field instead of a bit number. - The procedure
SysCtlClockSet()is dedicated specially to TM4C123 devices. Instead useg_ui32SysClock = SysCtlClockFreqSet((SYSCTL_OSC_MAIN | SYSCTL_XTAL_25MHZ | SYSCTL_USE_PLL | SYSCTL_CFG_VCO_320), 40000000); - For a Master clock setting do not use
SysCtlClockGet()procedure. This is also dedicated to TM4C123 devices. Instead useI2CMasterInitExpClk(I2C4_BASE, g_ui32SysClock, false);
Here is the updated code,
#include <stdint.h>
#include <stdbool.h>
#include "inc/hw_i2c.h"
#include "inc/hw_memmap.h"
#include "inc/hw_types.h"
#include "driverlib/gpio.h"
#include "driverlib/i2c.h"
#include "driverlib/pin_map.h"
#include "driverlib/sysctl.h"
#include "inc/tm4c129xnczad.h"
#define SLAVE_ADDRESS 0x3C
void delay (void)
{
volatile uint32_t ui32Loop;
for(ui32Loop = 0; ui32Loop < 200; ui32Loop++);
}
volatile uint32_t result;
uint32_t g_ui32SysClock;
int main(void)
{
g_ui32SysClock = SysCtlClockFreqSet((SYSCTL_OSC_MAIN | SYSCTL_XTAL_25MHZ | SYSCTL_USE_PLL | SYSCTL_CFG_VCO_320), 40000000);
//
// Enable the GPIO port that is used for the on-board LED.
//
SYSCTL_RCGCGPIO_R = SYSCTL_RCGCGPIO_R3 | SYSCTL_RCGCGPIO_R9 | SYSCTL_RCGCGPIO_R1;
//
// Do a dummy read to insert a few cycles after enabling the peripheral.
//
result = SYSCTL_RCGCGPIO_R;
//
// Enable the GPIO pin for the LED (PD3). Set the direction as output, and
// enable the GPIO pin for digital function.
//
GPIO_PORTD_AHB_DIR_R = 0x8;
GPIO_PORTD_AHB_DEN_R = 0x8;
SYSCTL_RCGCI2C_R = (1 << 4) | (1 << 6); // Mode Clock Gating Control for I2C modules 4 and 6
GPIOPinConfigure(GPIO_PK6_I2C4SCL);
GPIOPinConfigure(GPIO_PK7_I2C4SDA);
GPIOPinConfigure(GPIO_PB6_I2C6SCL);
GPIOPinConfigure(GPIO_PB7_I2C6SDA);
GPIOPinTypeI2C(GPIO_PORTK_BASE, (1 << 7)); // Configures SDA
GPIOPinTypeI2CSCL(GPIO_PORTK_BASE, (1 << 6)); // Configures SCL
GPIOPinTypeI2C(GPIO_PORTB_BASE, (1 << 7)); // Configures SDA
GPIOPinTypeI2CSCL(GPIO_PORTB_BASE, (1 << 6)); // Configures SCL
I2CMasterInitExpClk(I2C4_BASE, g_ui32SysClock, false);
I2CSlaveEnable(I2C6_BASE);
I2CSlaveInit(I2C6_BASE, SLAVE_ADDRESS);
I2CMasterSlaveAddrSet(I2C4_BASE, SLAVE_ADDRESS, false);
//
// Loop forever.
//
while(1)
{
//
// Turn on the LED.
//
GPIO_PORTD_AHB_DATA_R |= 0x8;
I2CMasterDataPut(I2C4_BASE, 0x33);
I2CMasterControl(I2C4_BASE, I2C_MASTER_CMD_SINGLE_SEND);
//
// Wait until the slave has received and acknowledged the data.
//
while(!(I2CSlaveStatus(I2C6_BASE) & I2C_SLAVE_ACT_RREQ));
//
// Read the data from the slave.
//
result = I2CSlaveDataGet(I2C6_BASE);
//
// Wait until master module is done transferring.
//
while(I2CMasterBusy(I2C4_BASE));
//
// Delay for a bit.
//
delay ();
//
// Turn off the LED.
//
GPIO_PORTD_AHB_DATA_R &= ~(0x8);
//
// Delay for a bit.
//
delay ();
}
}
Solution 2
I was able to get I2C working on TIVA Launchpad TM4C123GH6PM. I used the the Tivaware library. I created 3 functions, init and write. Here are the functions.
Initialization
void initI2C0(void)
{
SysCtlPeripheralEnable(SYSCTL_PERIPH_I2C0);
//reset I2C module
SysCtlPeripheralReset(SYSCTL_PERIPH_I2C0);
//enable GPIO peripheral that contains I2C
SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOB);
// Configure the pin muxing for I2C0 functions on port B2 and B3.
GPIOPinConfigure(GPIO_PB2_I2C0SCL);
GPIOPinConfigure(GPIO_PB3_I2C0SDA);
// Select the I2C function for these pins.
GPIOPinTypeI2CSCL(GPIO_PORTB_BASE, GPIO_PIN_2);
GPIOPinTypeI2C(GPIO_PORTB_BASE, GPIO_PIN_3);
// 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(I2C0_BASE, SysCtlClockGet(), false);
//clear I2C FIFOs
HWREG(I2C0_BASE + I2C_O_FIFOCTL) = 80008000;
}
I2C Write Function
void writeI2C0(uint16_t device_address, uint16_t device_register, uint8_t device_data)
{
//specify that we want to communicate to device address with an intended write to bus
I2CMasterSlaveAddrSet(I2C0_BASE, device_address, false);
//register to be read
I2CMasterDataPut(I2C0_BASE, device_register);
//send control byte and register address byte to slave device
I2CMasterControl(I2C0_BASE, I2C_MASTER_CMD_BURST_SEND_START);
//wait for MCU to finish transaction
while(I2CMasterBusy(I2C0_BASE));
I2CMasterSlaveAddrSet(I2C0_BASE, device_address, true);
//specify data to be written to the above mentioned device_register
I2CMasterDataPut(I2C0_BASE, device_data);
//wait while checking for MCU to complete the transaction
I2CMasterControl(I2C0_BASE, I2C_MASTER_CMD_BURST_RECEIVE_FINISH);
//wait for MCU & device to complete transaction
while(I2CMasterBusy(I2C0_BASE));
}
Complete code for TIVA + I2C can be found here.
Reference
Author by
MarcoPolo
Updated on June 04, 2022Comments
-
MarcoPolo almost 2 years
On a Tiva (Texas Instruments Cortex M4F ARM) TM4C129XNCZAD I have a problem with I2C interface. I have enabled both a master on I2C module 4 thru port K and a slave on I2C module 6 thru port B. I have interconnected both I2C modules. Using Texas Instruments driver library I tried to send 1 byte using I2C_MASTER_CMD_SINGLE_SEND command. I spend a lot of time to make it working, but SCK line keeps Low logical level. I followed exactly TivaWare™ Peripheral Driver Library USER’S GUIDE, but the communication doesn't work. Has anybody some experience with it?
There is my code:
#include <stdint.h> #include <stdbool.h> #include "inc/hw_i2c.h" #include "inc/hw_memmap.h" #include "inc/hw_types.h" #include "driverlib/gpio.h" #include "driverlib/i2c.h" #include "driverlib/pin_map.h" #include "driverlib/sysctl.h" #include "inc/tm4c129xnczad.h" #define SLAVE_ADDRESS 0x3C void delay (void) { volatile uint32_t ui32Loop; for(ui32Loop = 0; ui32Loop < 200000; ui32Loop++); } volatile uint32_t result; int main (void) { SysCtlClockSet(SYSCTL_SYSDIV_1 | SYSCTL_USE_OSC | SYSCTL_OSC_MAIN | SYSCTL_XTAL_16MHZ); // // Enable the GPIO port that is used for the on-board LED. // SYSCTL_RCGCGPIO_R = SYSCTL_RCGCGPIO_R3 | SYSCTL_RCGCGPIO_R9 | SYSCTL_RCGCGPIO_R1; // // Do a dummy read to insert a few cycles after enabling the peripheral. // result = SYSCTL_RCGCGPIO_R; // // Enable the GPIO pin for the LED (PD3). Set the direction as output, and // enable the GPIO pin for digital function. // GPIO_PORTD_AHB_DIR_R = 0x8; GPIO_PORTD_AHB_DEN_R = 0x8; GPIO_PORTK_DEN_R = 0xC0; // Enable Port K for I2C module 4 GPIO_PORTB_AHB_DEN_R = 0xC0; // Enable Port B for I2C module 6 SYSCTL_RCGCI2C_R = (1 << 4) | (1 << 6); // Mode Clock Gating Control for I2C modules 4 and 6 GPIO_PORTK_AFSEL_R = 0xC0; // Alternate Function Select PK6, PK7 GPIO_PORTB_AHB_AFSEL_R = 0xC0; // Alternate Function Select PB6, PB7 GPIOPinConfigure(GPIO_PK6_I2C4SCL); GPIOPinConfigure(GPIO_PK7_I2C4SDA); GPIOPinConfigure(GPIO_PB6_I2C6SCL); GPIOPinConfigure(GPIO_PB7_I2C6SDA); GPIOPinTypeI2C(GPIO_PORTK_BASE, 7); // Configurtes SDA GPIOPinTypeI2CSCL(GPIO_PORTK_BASE, 6); // Configurtes SCL GPIOPinTypeI2C(GPIO_PORTB_BASE, 7); // Configurtes SDA GPIOPinTypeI2CSCL(GPIO_PORTB_BASE, 6); // Configurtes SCL I2CMasterInitExpClk(I2C4_BASE, SysCtlClockGet(), false); I2CSlaveEnable(I2C6_BASE); I2CSlaveInit(I2C6_BASE, SLAVE_ADDRESS); I2CMasterSlaveAddrSet(I2C4_BASE, SLAVE_ADDRESS, false); // // Loop forever. // while(1) { // // Turn on the LED. // GPIO_PORTD_AHB_DATA_R |= 0x8; I2CMasterDataPut(I2C4_BASE, 0x33); I2CMasterControl(I2C4_BASE, I2C_MASTER_CMD_SINGLE_SEND); // // Wait until the slave has received and acknowledged the data. // while(!(I2CSlaveStatus(I2C6_BASE) & I2C_SLAVE_ACT_RREQ)); // // Read the data from the slave. // result = I2CSlaveDataGet(I2C6_BASE); // // Wait until master module is done transferring. // while(I2CMasterBusy(I2C4_BASE)); // // Delay for a bit. // delay (); // // Turn off the LED. // GPIO_PORTD_AHB_DATA_R &= ~(0x8); // // Delay for a bit. // delay (); } } -
Mahendra Gunawardena over 8 years@Parag The code word as it is, why do you want to change the code. The complete code is on github
