Dear sir/mam
I'm trying to interface ADXL345 accelerometer with msp430fr5994 by using SPI. When i run the program I'm getting dummy value as 0XFF on transmit buffer.Im sharing the code here.I have used header file as SDK of standared master_spi. Please solve my mistake.
#include <msp430.h>
#include <spi.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
unsigned char addr[30]="";
void initSPI()
{
//Clock Polarity: The inactive state is high
//MSB First, 8-bit, Master, 3-pin mode, Synchronous
UCB1CTLW0 = UCSWRST; // **Put state machine in reset
UCB1CTLW0 |= UCCKPL | UCMSB | UCSYNC
| UCMST | UCSSEL__SMCLK; // 3-pin, 8-bit SPI Slave SMCLK=16MHZ
UCB1BRW = 0x160; //16000000/160=100KHZ
//UCB1MCTLW = 0;
UCB1CTLW0 &= ~UCSWRST; // **Initialize USCI state machine**
UCB1IE |= UCRXIE; // Enable USCI0 RX interrupt
}
void initGPIO()
{
//LEDs
COMMS_LED_DIR |= COMMS_LED_PIN;
COMMS_LED_OUT &= ~COMMS_LED_PIN;
BUTTON_LED_DIR |= BUTTON_LED_PIN;
BUTTON_LED_OUT &= ~BUTTON_LED_PIN;
// Configure SPI
P5SEL0 |= BIT0 | BIT1 | BIT2;
SLAVE_RST_DIR |= SLAVE_RST_PIN;
SLAVE_RST_OUT |= SLAVE_RST_PIN;
SLAVE_CS_DIR |= SLAVE_CS_PIN;
SLAVE_CS_OUT |= SLAVE_CS_PIN;
//Button to initiate transfer
BUTTON_DIR &= ~(BUTTON_PIN); // button input
BUTTON_OUT |= BUTTON_PIN; // button pull up
BUTTON_REN |= BUTTON_PIN; // button pull up/down resistor enable
BUTTON_IES |= BUTTON_PIN; // button Hi/lo edge
BUTTON_IE |= BUTTON_PIN; // button interrupt enabled
// Disable the GPIO power-on default high-impedance mode to activate
// previously configured port settings
PM5CTL0 &= ~LOCKLPM5;
BUTTON_IFG &= ~BUTTON_PIN; // button IFG cleared
}
void initClockTo16MHz()
{
// Configure one FRAM waitstate as required by the device datasheet for MCLK
// operation beyond 8MHz _before_ configuring the clock system.
FRCTL0 = FRCTLPW | NWAITS_1;
// Clock System Setup
CSCTL0_H = CSKEY_H; // Unlock CS registers
CSCTL1 = DCOFSEL_0; // Set DCO to 1MHz
// Set SMCLK = MCLK = DCO, ACLK = LFXTCLK (VLOCLK if unavailable)
CSCTL2 = SELA__LFXTCLK | SELS__DCOCLK | SELM__DCOCLK;
// Per Device Errata set divider to 4 before changing frequency to
// prevent out of spec operation from overshoot transient
CSCTL3 = DIVA__4 | DIVS__4 | DIVM__4; // Set all corresponding clk sources to divide by 4 for errata
CSCTL1 = DCOFSEL_4 | DCORSEL; // Set DCO to 16MHz
// Delay by ~10us to let DCO settle. 60 cycles = 20 cycles buffer + (10us / (1/4MHz))
__delay_cycles(60);
CSCTL3 = DIVA__1 | DIVS__1 | DIVM__1; // Set all dividers to 1 for 16MHz operation
CSCTL0_H = 0; // Lock CS registers
}
int adxl_device_id()
{
unsigned int id;
SPI_Master_ReadReg(CMD_TYPE_0_SLAVE,TYPE_0_LENGTH);
id=ReceiveBuffer[0];
return id;
}
int main(void) {
WDTCTL = WDTPW | WDTHOLD; // Stop watchdog timer
initClockTo16MHz();
initGPIO();
initSPI();
SLAVE_RST_OUT &= ~SLAVE_RST_PIN; // Now with SPI signals initialized,
__delay_cycles(100000);
SLAVE_RST_OUT |= SLAVE_RST_PIN; // reset slave
__delay_cycles(100000); // Wait for slave to initialize
COMMS_LED_OUT |= COMMS_LED_PIN;
while(1)
{
int adxl_id;
adxl_id=adxl_device_id();
}
return 0;
}
