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I am using a MicroChip's DSPIC33FJ128MC802 with a LIS3LV02DL accelerometer (ST Micro). I am having trouble communicating with the accelerometer. The SPI in 16bit mode and with Microcontroller as Master. Below, is the code I use to request the OUTX_L from the accelerometer.
I see the MOSI and SCK on PicoScope fine, and the Chip Select goes low right before the MOSI/SCK and goes back high after it. However, I do not see any signals coming back on the MISO, on the scope. All I see is noise. The values in 'tempm' variable is always 0xFFFF. Same thing with WhoAmI. I checked all the connections too and they seem fine. What am I doing wrong? Any suggestions? Thank you.
I am using MPLAB IDE v8.76 with an MPLAB ICD3.
Rich (BB code):
PORTBbits.RB13 = 0; //Lower SS line for accelerometer
// Delay_us_ms('u', 0x6);
temp = SPI1BUF; //Dummy read
SPI1BUF = 0xA800; //get low axis Bit15 set for Read
// while (!SPI1STATbits.SPITBF){}; //Wait for data to be sent
// while (SPI1STATbits.SPITBF){}; //Wait for data to be sent i.e flag to be cleared
while(!IFS0bits.SPI1IF){};
IFS0bits.SPI1IF = 0;
while (!SPI1STATbits.SPIRBF){}; //Wait for data to be received
tempm = SPI1BUF;
PORTBbits.RB13 = 1; //Raise SS line for accelerometer
Delay_us_ms('u', 0x6);
Rich (BB code):
void Init_Accel_Over_SPI(void)
{
int temp;
//hard defines are the only way the SPI will send this info
Init_SPI1_For_Word();
Delay_us_ms('u', 0x0A);
//**** accel set up ******
PORTBbits.RB13 = 0; //Lower SS line for accelerometer
// Delay_us_ms('u', 0x0A);
temp = SPI1BUF; //Dummy read
SPI1BUF = Write_CTRL_REG1; //(0x20, 0b011010111) CTRL_REG1: Device On, 160Hz, No self test, Enable all Axis
// while (!SPI1STATbits.SPITBF){}; //Wait for data to be sent
// while (SPI1STATbits.SPITBF){}; //Wait for flag to be cleared
while(!IFS0bits.SPI1IF){};
IFS0bits.SPI1IF = 0;
PORTBbits.RB13 = 1; //Raise SS line for accelerometer
Delay_us_ms('u', 0x0A);
//********************
PORTBbits.RB13 = 0; //Lower SS line for accelerometer
// Delay_us_ms('u', 0x0A);
temp = SPI1BUF; //Dummy read
SPI1BUF = Write_CTRL_REG2; //(0x21, 0b01110101) CTRL_REG2: 2G, BDU=1; big endian, boot NOT, DTR, 4Wire, 16 bit
while(!IFS0bits.SPI1IF){};
IFS0bits.SPI1IF = 0;
PORTBbits.RB13 = 1; //Raise SS line for accelerometer
Delay_us_ms('u', 0x0A);
//********************
PORTBbits.RB13 = 0; //Lower SS line for accelerometer
// Delay_us_ms('u', 0x0A);
temp = SPI1BUF; //Dummy read
SPI1BUF = Write_CTRL_REG3; //(0x22, 0b00010011) CTRL_REG3: Int clock, Filter Enabled, FDSEnabled, HPC=4096
while(!IFS0bits.SPI1IF){};
IFS0bits.SPI1IF = 0;
PORTBbits.RB13 = 1; //Raise SS line for accelerometer
Delay_us_ms('u', 0x0A);
} //end Init_Accel_Over_SPI
void Init_SPI1_For_Word(void)
{
SPI1STATbits.SPIEN = 0; //Disable SPI1
IFS0bits.SPI1IF = 0; //Clear interrupt flag for SPI1
IEC0bits.SPI1IE = 0; //Disable SPI interrupt
//*******
SPI1CON1bits.DISSCK = 0; //Use Internal serial clock
SPI1CON1bits.DISSDO = 0; //SPI1 SDO controlled by SPI1 controller
SPI1CON1bits.MODE16 = 1; //Communication is word wide (16-bit)
//SPI1CON1bits.SPRE = 0; //Set secondary prescaler to 8:1
SPI1CON1bits.SPRE = 6; //change to 2:1
SPI1CON1bits.PPRE = 0; //Set primary prescaler to 64:1
SPI1CON1bits.MSTEN = 1; //SP11 mode is master mode
SPI1CON1bits.SMP = 1; //Sample input data at middle of data output time
//**********************
SPI1CON1bits.CKE = 1; //Serial out data changes on transition from active clock state to idle clock state
// SPI1CON1bits.CKE = 0; // Serial out data changes from on transition from active clock state to idle clock state
SPI1CON1bits.SSEN = 1; // SSx pin not used by module. Pin controlled by port function
//**********************
SPI1CON1bits.CKP = 1; //Idle state for clock is high level; active is low
//**********************
SPI1STATbits.SPIROV = 0; //Clear SPI1 Receive overflow flag
SPI1STATbits.SPISIDL = 0;
SPI1STATbits.SPITBF = 0;
// SPI1STATbits.SPIRBF = 0;
SPI1CON2bits.FRMEN = 0; // Framed SPIx support disabled
SPI1STATbits.SPIEN = 1; //Enable SPI1
IFS0bits.SPI1IF = 0; //Clear interrupt flag for SPI1.
IEC0bits.SPI1IE = 0; //Disable SPI interrupt
} // end Init_SPI1_For_Word()I am using MPLAB IDE v8.76 with an MPLAB ICD3.
