Hi,
I am working on communicating with the ADXL345 accelerometer and my code works fine when I single step debug through the program, however when I run it freely it gets stuck in low power mode after a transmit. Here is the code:
// Interfacing ADXL345 accelerometer with MSP430G2553 with I2C communication // // /|\ /|\ // ADXL345 10k 10k MSP430G2xx3 // slave | | master // ----------------- | | ----------------- // | SDA|<-|---+->|P3.1/UCB0SDA XIN|- // | | | | | // | | | | XOUT|- // | SCL|<-+----->|P3.2/UCB0SCL | // | | | | // // Attribute: Code modified from I2C multiple byte TX/RX Master example by // D. Dang // Texas Instruments Inc. // // Code Made By : // Prof. Ravi Butani // Marwadi Education Foundation, Rajkot GUJARAT-INDIA // ravi.butani@marwadieducation.edu.in // // Code Released under Creative Commons By-SA license // Visit creativecommons.org/.../deed.en_US to know more about license // Built with CCS Version 5.1.0 //****************************************************************************** #include <msp430.h> #define NUM_BYTES_TX 2 // How many bytes? #define NUM_BYTES_RX 6 #define ADXL_345 0x53 int RXByteCtr, RPT_Flag = 0,x1,y1,z1; // enables repeated start when 1 volatile unsigned char RxBuffer[6]; // Allocate 6 byte of RAM unsigned char *PRxData; // Pointer to RX data unsigned char TXByteCtr, RX = 0; unsigned char MSData[3]; void Setup_TX(unsigned char); void Setup_RX(unsigned char); void Transmit(unsigned char,unsigned char); void Receive(void); int main(void) { WDTCTL = WDTPW + WDTHOLD; // Stop WDT P1SEL |= BIT6 + BIT7; // Assign I2C pins to USCI_B0 P1SEL2|= BIT6 + BIT7; // Assign I2C pins to USCI_B0 P1DIR |= BIT0; // Init sequence for ADXL345 //Transmit process Setup_TX(ADXL_345); RPT_Flag = 1; Transmit(0x2D,0x00); while (UCB0CTL1 & UCTXSTP); // Ensure stop condition got sent //Transmit process Setup_TX(ADXL_345); RPT_Flag = 1; Transmit(0x2D,0x10); while (UCB0CTL1 & UCTXSTP); // Ensure stop condition got sent //Transmit process Setup_TX(ADXL_345); RPT_Flag = 1; Transmit(0x2D,0x08); while (UCB0CTL1 & UCTXSTP); // Ensure stop condition got sent // Un-comment next block to change range of ADXL345 /* Setup_TX(ADXL_345); RPT_Flag = 1; Transmit(0x31,0x01); // Range Select at add 0x31 write 0x00 for 2g(default)/ 0x01 for 4g/ 0x02 for 8g/ 0x03 for 16g while (UCB0CTL1 & UCTXSTP); // Ensure stop condition got sent */ while(1){ //Transmit process Setup_TX(ADXL_345); RPT_Flag = 1; Transmit(0x32,0xFE); // Request Data from ADXL345 in 2g Range 10Bit resolution while (UCB0CTL1 & UCTXSTP); // Ensure stop condition got sent //Receive process Setup_RX(ADXL_345); Receive(); while (UCB0CTL1 & UCTXSTP); // Ensure stop condition got sent x1 = (((int)RxBuffer[1]) << 8) | RxBuffer[0]; y1 = (((int)RxBuffer[3]) << 8) | RxBuffer[2]; z1 = (((int)RxBuffer[5]) << 8) | RxBuffer[4]; // now You have XYZ axis reading in x1,x2,x3 variable....Bingo... you can play with it as you like.... // Below if sense x and y angle and Red led is on if its more then 45 or less then -45... // you can put your own condition here... if ((x1 > 128) || (y1 > 128) || (x1 < -128) || (y1 < -128)) { P1OUT |= BIT0; // red led on } else { P1OUT &= ~BIT0; // red led off } __delay_cycles(10000); // sample rate ~100 samples/sec // you can change by changing delay } } //------------------------------------------------------------------------------- // The USCI_B0 data ISR is used to move received data from the I2C slave // to the MSP430 memory. It is structured such that it can be used to receive // any 2+ number of bytes by pre-loading RXByteCtr with the byte count. //------------------------------------------------------------------------------- #pragma vector = USCIAB0TX_VECTOR __interrupt void USCIAB0TX_ISR(void) { if(RX == 1){ // Master Recieve? RXByteCtr--; // Decrement RX byte counter if (RXByteCtr) { *PRxData++ = UCB0RXBUF; // Move RX data to address PRxData } else { if(RPT_Flag == 0) UCB0CTL1 |= UCTXSTP; // No Repeated Start: stop condition if(RPT_Flag == 1){ // if Repeated Start: do nothing RPT_Flag = 0; } *PRxData = UCB0RXBUF; // Move final RX data to PRxData __bic_SR_register_on_exit(CPUOFF); // Exit LPM0 }} else{ // Master Transmit if (TXByteCtr) // Check TX byte counter { UCB0TXBUF = MSData[TXByteCtr]; // Load TX buffer TXByteCtr--; // Decrement TX byte counter } else { if(RPT_Flag == 1){ RPT_Flag = 0; TXByteCtr = NUM_BYTES_TX; // Load TX byte counter __bic_SR_register_on_exit(CPUOFF); } else{ UCB0CTL1 |= UCTXSTP; // I2C stop condition IFG2 &= ~UCB0TXIFG; // Clear USCI_B0 TX int flag __bic_SR_register_on_exit(CPUOFF); // Exit LPM0 } } } } void Setup_TX(unsigned char Dev_ID){ _DINT(); RX = 0; IE2 &= ~UCB0RXIE; while (UCB0CTL1 & UCTXSTP); // Ensure stop condition got sent// Disable RX interrupt UCB0CTL1 |= UCSWRST; // Enable SW reset UCB0CTL0 = UCMST + UCMODE_3 + UCSYNC; // I2C Master, synchronous mode UCB0CTL1 = UCSSEL_2 + UCSWRST; // Use SMCLK, keep SW reset UCB0BR0 = 12; // fSCL = SMCLK/12 = ~100kHz UCB0BR1 = 0; UCB0I2CSA = Dev_ID; // Slave Address is 048h UCB0CTL1 &= ~UCSWRST; // Clear SW reset, resume operation IE2 |= UCB0TXIE; // Enable TX interrupt } void Setup_RX(unsigned char Dev_ID){ _DINT(); RX = 1; IE2 &= ~UCB0TXIE; UCB0CTL1 |= UCSWRST; // Enable SW reset UCB0CTL0 = UCMST + UCMODE_3 + UCSYNC; // I2C Master, synchronous mode UCB0CTL1 = UCSSEL_2 + UCSWRST; // Use SMCLK, keep SW reset UCB0BR0 = 12; // fSCL = SMCLK/12 = ~100kHz UCB0BR1 = 0; UCB0I2CSA = Dev_ID; // Slave Address is 048h UCB0CTL1 &= ~UCSWRST; // Clear SW reset, resume operation IE2 |= UCB0RXIE; // Enable RX interrupt } void Transmit(unsigned char Reg_ADD,unsigned char Reg_DAT){ MSData[2]= Reg_ADD; MSData[1]= Reg_DAT; TXByteCtr = NUM_BYTES_TX; // Load TX byte counter while (UCB0CTL1 & UCTXSTP); // Ensure stop condition got sent UCB0CTL1 |= UCTR + UCTXSTT; // I2C TX, start condition __bis_SR_register(CPUOFF + GIE); // Enter LPM0 w/ interrupts } void Receive(void){ PRxData = (unsigned char *)RxBuffer; // Start of RX buffer RXByteCtr = NUM_BYTES_RX-1; // Load RX byte counter while (UCB0CTL1 & UCTXSTP); // Ensure stop condition got sent UCB0CTL1 |= UCTXSTT; // I2C start condition __bis_SR_register(CPUOFF + GIE); // Enter LPM0 w/ interrupts }
Any explanation as to why this is happening?
Thanks,
Micah
