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/**
* This is most complex and difficult device.
* It realize "read through write" paradigm. This is not standard, but
* most of I2C devices use this paradigm.
* You must write to device reading address, send restart to bus,
* and then begin reading process.
*/
#include <stdlib.h>
#include "ch.h"
#include "hal.h"
#include "lis3.h"
// buffers
static i2cblock_t accel_rx_data[ACCEL_RX_DEPTH];
static i2cblock_t accel_tx_data[ACCEL_TX_DEPTH];
/* Error trap */
static void i2c_lis3_error_cb(I2CDriver *i2cp, I2CSlaveConfig *i2cscfg){
(void)i2cscfg;
int status = 0;
status = i2cp->id_i2c->SR1;
while(TRUE);
}
// Accelerometer lis3lv02dq config
static I2CSlaveConfig lis3 = {
NULL,
i2c_lis3_error_cb,
accel_rx_data,
ACCEL_RX_DEPTH,
0,
0,
accel_tx_data,
ACCEL_TX_DEPTH,
0,
0,
0b0011101,
FALSE,
};
/**
* This treading need for convenient realize
* "read through write" process.
*/
static WORKING_AREA(I2CAccelThreadWA, 128);
static Thread *i2c_accel_tp = NULL;
static msg_t I2CAccelThread(void *arg) {
(void)arg;
int16_t acceleration_x = 0;
int16_t acceleration_y = 0;
int16_t acceleration_z = 0;
I2CDriver *i2cp;
msg_t msg;
while (TRUE) {
/* Waiting for wake up */
chSysLock();
i2c_accel_tp = chThdSelf();
chSchGoSleepS(THD_STATE_SUSPENDED);
msg = chThdSelf()->p_msg; /* Retrieving the message, optional.*/
chSysUnlock();
/***************** Perform processing here. ***************************/
i2cp = (I2CDriver *)msg;
/* collect measured data */
acceleration_x = lis3.rxbuf[0] + (lis3.rxbuf[1] << 8);
acceleration_y = lis3.rxbuf[2] + (lis3.rxbuf[3] << 8);
acceleration_z = lis3.rxbuf[4] + (lis3.rxbuf[5] << 8);
}
return 0;
}
/* This callback raise up when transfer finished */
static void i2c_lis3_cb(I2CDriver *i2cp, I2CSlaveConfig *i2cscfg){
if (i2cp->id_slave_config->restart){ // is it restart flag set to TRUE
/* reset restart flag */
i2cp->id_slave_config->restart = FALSE;
/* now send restart and read acceleration data.
* Function i2cMasterReceive() send restart implicitly. */
i2cMasterReceive(i2cp, i2cscfg);
}
else{
/* If jump here than requested data have been read.
* Stop communication, release bus and wake up processing thread */
i2cMasterStop(i2cp);
i2cReleaseBus(&I2CD1);
// wake up heavy thread for data processing
if (i2c_accel_tp != NULL) {
i2c_accel_tp->p_msg = (msg_t)i2cp;
chSchReadyI(i2c_accel_tp);
i2c_accel_tp = NULL;
}
}
}
/**
* Init function. Here we will also start personal serving thread.
*/
int init_lis3(void){
/* Starting the accelerometer serving thread.*/
i2c_accel_tp = chThdCreateStatic(I2CAccelThreadWA,
sizeof(I2CAccelThreadWA),
HIGHPRIO,
I2CAccelThread,
NULL);
/* wait thread statup */
while (i2c_accel_tp == NULL)
chThdSleepMilliseconds(1);
lis3.txbufhead = 0;
lis3.rxbufhead = 0;
/* Write configuration data */
lis3.txbytes = 4;
/* fill transmit buffer. See datasheet to understand what we write */
lis3.txbuf[0] = ACCEL_CTRL_REG1 | AUTO_INCREMENT_BIT;
lis3.txbuf[1] = 0b11100111;
lis3.txbuf[2] = 0b01000001;
lis3.txbuf[3] = 0b00000000;
/* setting callback */
lis3.id_callback = i2c_lis3_cb;
i2cAcquireBus(&I2CD1);
/* sending */
i2cMasterTransmit(&I2CD1, &lis3);
return 0;
}
/**
*
*/
void request_acceleration_data(void){
/* fill transmit buffer with address of register that we want to read */
lis3.txbufhead = 0;
lis3.txbuf[0] = ACCEL_OUT_DATA | AUTO_INCREMENT_BIT; // register address
lis3.txbytes = 1;
/* tune receive structures */
lis3.rxbufhead = 0;
lis3.rxbytes = 6;
/* Now it is most important action. We must set restart flag to TRUE.
* And in callback function we must reset it to FALSE after sending
* of register address. In TMP75 and MAX1236 this flag does not use. */
lis3.restart = TRUE;
/* talk to slave what we want from it */
i2cAcquireBus(&I2CD1);
i2cMasterTransmit(&I2CD1, &lis3);
}
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