Dear TI Community I am trying to Interface LM75 with MSP430f5510 and the firware is written using DriverLib
I believe I have done the configuration correctly, When i try to send Data via I2C
using USCI_B_I2C_masterSendSingleByte() , it send the data and hangs waiting for TX Interrupt -
Both SDA and SCL lines are pulled up using 10k resistor
I am new to LM75 - from what i gathered from TI Data sheet was that we need to send 0x00 to LM75 and it will return temperature
What i dont understand is that first should we send Address and follwed by pointer or just the pointer is enough ?
Either way I am stuck well before that it is successfully sending Start Condition and once it send data it freezes
Kindly help me
Below is my code
#include "driverlib.h"
// LM75
#define I2CBASE USCI_B1_BASE
#define SDA GPIO_PIN1
#define SCL GPIO_PIN2
//Set the address for slave module. This is a 7-bit address sent in the following format:
//[A6:A5:A4:A3:A2:A1:A0:RS]
#define LM75_ADDRESS 0x48
unsigned char receiveCount = 0;
void main(void)
{
//Flash Firmware onto MSP430F5510
// Stop watchdog timer
WDT_A_hold(WDT_A_BASE);
// Enable Global Interrupts
__bis_SR_register( GIE );
// Initialize Peripherals
Init_Clock();
Init_LM75();
while(1)
{
USCI_B_I2C_masterSendSingleByte(I2CBASE, LM75_ADDRESS);
//Delay until transmission completes
while(USCI_B_I2C_isBusBusy(I2CBASE))
{
;
}
receiveCount = RXCOUNT;
// Initialize multi reception
USCI_B_I2C_setMode(I2CBASE, USCI_B_I2C_RECEIVE_MODE );
USCI_B_I2C_masterReceiveMultiByteStart(I2CBASE);
__delay_cycles(90000000);
UARTSendInit(RxBuffer[0]);
UARTSendInit(RxBuffer[1]);
}
}
#pragma vector=USCI_B1_VECTOR
__interrupt void USCI_B1_ISR(void)
{
switch(__even_in_range(UCB1IV,12))
{
case USCI_I2C_UCRXIFG:
{
//Decrement RX byte counter
receiveCount--;
if(receiveCount)
{
if(receiveCount == 1)
{
//Initiate end of reception -> Receive byte with NAK
RxBuffer[RxIndex++] = USCI_B_I2C_masterReceiveMultiByteFinish( I2CBASE );
}
else
{
//Keep receiving one byte at a time
RxBuffer[RxIndex++] = USCI_B_I2C_masterReceiveMultiByteNext( I2CBASE );
}
}
else
{
//Receive last byte
RxBuffer[RxIndex++] = USCI_B_I2C_masterReceiveMultiByteNext( I2CBASE );
}
break;
}
case USCI_I2C_UCTXIFG:
{
__no_operation();
break;
}
}
}
//Initialize Clock
void Init_Clock(void)
{
//Set VCore = 3 for 25MHz clock
PMM_setVCore(PMM_CORE_LEVEL_3);
// //ACLK, MCLK, MCLK set out to pins
// GPIO_setAsPeripheralModuleFunctionOutputPin(
// GPIO_PORT_P11,
// GPIO_PIN0 + GPIO_PIN1 + GPIO_PIN2
// );
//Set DCO FLL reference = REFO
UCS_initClockSignal(
UCS_FLLREF,
UCS_REFOCLK_SELECT,
UCS_CLOCK_DIVIDER_1
);
//VLO Clock Sources ACLK (9.4kHz)
UCS_initClockSignal(
UCS_ACLK,
UCS_VLOCLK_SELECT,
UCS_CLOCK_DIVIDER_1
);
//Set Ratio and Desired MCLK Frequency and initialize DCO
UCS_initFLLSettle(
UCS_MCLK_DESIRED_FREQUENCY_IN_KHZ,
UCS_MCLK_FLLREF_RATIO
);
// Enable global oscillator fault flag
SFR_clearInterrupt(SFR_OSCILLATOR_FAULT_INTERRUPT);
SFR_enableInterrupt(SFR_OSCILLATOR_FAULT_INTERRUPT);
// Enable global interrupt
__bis_SR_register(GIE);
}
void Init_LM75(void)
{
//Assign I2C pins to USCI_B1
GPIO_setAsPeripheralModuleFunctionInputPin(
UART_SPI_Port, SDA + SCL );
//Initialize Master
USCI_B_I2C_initMasterParam param = {0};
param.selectClockSource = USCI_B_I2C_CLOCKSOURCE_ACLK;
param.i2cClk = UCS_getACLK();
param.dataRate = USCI_B_I2C_SET_DATA_RATE_100KBPS;
USCI_B_I2C_initMaster(I2CBASE, ¶m);
//Specify slave address
USCI_B_I2C_setSlaveAddress(I2CBASE, LM75_ADDRESS);
//Set Master in transmit mode
USCI_B_I2C_setMode(I2CBASE, USCI_B_I2C_TRANSMIT_MODE );
//Enable I2C Module to start operations
USCI_B_I2C_enable(I2CBASE);
//Enable master Receive interrupt
USCI_B_I2C_clearInterrupt(I2CBASE, USCI_B_I2C_RECEIVE_INTERRUPT );
USCI_B_I2C_enableInterrupt(I2CBASE, USCI_B_I2C_RECEIVE_INTERRUPT );
//Enable TX interrupt
USCI_B_I2C_clearInterrupt(I2CBASE,
USCI_B_I2C_TRANSMIT_INTERRUPT
);
USCI_B_I2C_enableInterrupt(I2CBASE,
USCI_B_I2C_TRANSMIT_INTERRUPT
);
}
void USCI_B_I2C_masterSendSingleByte(uint16_t baseAddress,
uint8_t txData)
{
//Store current TXIE status
uint8_t txieStatus = HWREG8(baseAddress + OFS_UCBxIE) & UCTXIE;
//Disable transmit interrupt enable
HWREG8(baseAddress + OFS_UCBxIE) &= ~(UCTXIE);
//Send start condition.
HWREG8(baseAddress + OFS_UCBxCTL1) |= UCTR + UCTXSTT;
//Poll for transmit interrupt flag.
while(!(HWREG8(baseAddress + OFS_UCBxIFG) & UCTXIFG))
{
}
//Send single byte data.
HWREG8(baseAddress + OFS_UCBxTXBUF) = txData;
//Poll for transmit interrupt flag.
while(!(HWREG8(baseAddress + OFS_UCBxIFG) & UCTXIFG))
{
}
//Send stop condition.
HWREG8(baseAddress + OFS_UCBxCTL1) |= UCTXSTP;
//Clear transmit interrupt flag before enabling interrupt again
HWREG8(baseAddress + OFS_UCBxIFG) &= ~(UCTXIFG);
//Reinstate transmit interrupt enable
HWREG8(baseAddress + OFS_UCBxIE) |= txieStatus;
}
