Hi,
My developing environments:
TM4C1294 custom board, FreeRTOS v7.1.1, LWIP 1.4.1, CCS 6.0.1
I am working on detecting fail bits from I2C expander, and there is only one Master which is MCU.
I thought it worked well since I could read the right values(4 bytes) from the expander. However, it suddenly stops working after running 2~3 hours.(both SDA and SCL go high).
The task,I2CTask in my project, is executed in a regular time basis and read values.
Here is my I2C init funciton:
void i2c_init(void)
{
// The I2C5 peripheral must be enabled before use.
ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_I2C5);
while(!(ROM_SysCtlPeripheralReady(SYSCTL_PERIPH_I2C5)));
ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOB);
while(!(ROM_SysCtlPeripheralReady(SYSCTL_PERIPH_GPIOB)));
ROM_GPIOPinConfigure(GPIO_PB0_I2C5SCL);
ROM_GPIOPinConfigure(GPIO_PB1_I2C5SDA);
// Select the I2C function for these pins. This function will also
// configure the GPIO pins for I2C operation, setting them to
// open-drain operation with weak pull-ups.
ROM_GPIOPinTypeI2CSCL(GPIO_PORTB_BASE, GPIO_PIN_0);
ROM_GPIOPinTypeI2C(GPIO_PORTB_BASE, GPIO_PIN_1 );
// Initialize Master and Slave
// true: 400kbps I2C clock (false: 100kbps)
ROM_I2CMasterInitExpClk(I2C5_BASE, g_ui32SysClock, false);
}
Also here is read function:
unsigned long read32_PCA9506()
{
int err[2]; //used for debugging
int i,loopdelay; // delay loop variable
unsigned char byte[4]; // 4 byte array for retrieved bytes holding
// unsigned char byte1,byte2,byte3,byte4 ; // holders for the 4 retrieved bytes
unsigned long return_fails = 0; // 32bit return holder of assembled bytes
// Program the SLAVE address into registers, and select a WRITE operation
// for I2C bus
ROM_I2CMasterSlaveAddrSet(I2C5_BASE, PCA9506_ADDR, I2C_SEND);//PCA9506_ADDR:0x20
// Note: The I^2C bus requires us to transmit the ' START ' condition
// from the Micro to the PCA9506. The next byte transfered must be the
// address of the slave device. A0,A1,A2 of PCA9506 are tied low (000).
// The address is the 7 MSB of a byte, with the LSB being the R/W selection bit.
// For our configuration, 0x20 is the address of the PCA9506
// The address is loaded into Slave address register, then the register
// address byte is loaded into a write register with the type of 'START'
// configuration we want to use.... START toggle is sent, then slave address
// goes out automatically, then register to write too is transmitted.
// Load Slave address, select type of START transmission, and write
// register address to OUTPUT write register for I2C0
ROM_I2CMasterDataPut( I2C5_BASE, COMMAND_REG);//COMMAND_REG: 0x80
// Transmit START, slave address, -- NO STOP sent
ROM_I2CMasterControl( I2C5_BASE, I2C_MASTER_CMD_BURST_SEND_START );
while (!(ROM_I2CMasterBusy( I2C5_BASE ))) {} //sometime does not catch flag,so put this code
while (ROM_I2CMasterBusy( I2C5_BASE )) {} // wait for transmission to finish
err[0] = ROM_I2CMasterErr(I2C5_BASE); // read the error status of last transmission and
if ( err[0] != I2C_MASTER_ERR_NONE )
{
UARTprintf("error[0] = %x\n",err[0] );
// error detected during START BURST MODE, SEND STOP COMMAND
ROM_I2CMasterControl( I2C5_BASE, I2C_MASTER_CMD_BURST_SEND_ERROR_STOP );
// ROM_I2CMasterIntClear(I2C5_BASE);
I2C5_error_count = (I2C5_error_count + 1); // increment the detected error counter for I2C0
return_fails = 0;
return (unsigned long) return_fails; // return from READ function, reporting no
// FAIL bit status, but with error count increased
}
ROM_I2CMasterSlaveAddrSet( I2C5_BASE, PCA9506_ADDR, I2C_RECV );
//repeat start condition followed by receive operation with data negative acknowledge
//master goes to Master receive state
ROM_I2CMasterControl( I2C5_BASE, I2C_MASTER_CMD_BURST_RECEIVE_START );
for ( i=0; i<4; i++)
{
while (!ROM_I2CMasterBusy( I2C5_BASE ));
while (ROM_I2CMasterBusy( I2C5_BASE )){}
// BYTE 1 - IO-O HAS NOW BEEN READ, SO RETRIEVE THE VALUE AND STORE IT IN return
byte[i] = ROM_I2CMasterDataGet( I2C5_BASE );
UARTprintf("Data Get: byte[%d] == %x\n", i, byte[i]);
ROM_I2CMasterControl(I2C5_BASE, I2C_MASTER_CMD_BURST_RECEIVE_CONT);
err[1] = ROM_I2CMasterErr(I2C5_BASE);
if ( err[1] != I2C_MASTER_ERR_NONE )
{
UARTprintf("error[1] = %x\n",err[2] );
// error detected during START BURST MODE, SEND STOP COMMAND
ROM_I2CMasterControl( I2C5_BASE, I2C_MASTER_CMD_BURST_RECEIVE_ERROR_STOP );
// ROM_I2CMasterIntClear(I2C5_BASE);
I2C5_error_count = (I2C5_error_count + 1); // increment the detected error counter for I2C5
return_fails = 0;
return (unsigned long) return_fails; // return from READ function, reporting no
// FAIL bit status, but with error count increased
}
for(loopdelay=0; loopdelay<1000; loopdelay++);//8.33 uSec
}//end for
return_fails = (byte[3] << 24) | (byte[2] << 16) | (byte[1] << 8) | byte[0]; // assemble 32bit FAIL register
// all 4 registers have now been read, so transmit the STOP signal to IC2 slave
// transmit a receive stop condition - Current State is receive - write 0x04 to I2CMCS register
// with NO acknowledge to put I2C bus into IDLE state
ROM_I2CMasterControl( I2C5_BASE, I2C_MASTER_CMD_BURST_RECEIVE_FINISH ); // transmit STOP only to free up bus
I2C5_error_count = 0; // if we reach this point, we have successfully completed
// a read process of 32 bits ( 4 bytes ) from the PCA9506 chip
for(loopdelay=0; loopdelay<1000; loopdelay++);
return (unsigned long) return_fails;
}
I have not found what is wrong with this.
As you see this is the polling mode, so may be better to use interrupt mode? if then can you give a tip to use interrupt mode in my situation like sending and receiving 4 bytes?
Thanks,
Jin
