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/**
* Maxim ADC has not so suitable default settings after startup.
* So we will create init function to tune this ADC.
*/
#include <stdlib.h>
#include "ch.h"
#include "hal.h"
#include "max1236.h"
// Data buffers
static i2cblock_t max1236_rx_data[MAX1236_RX_DEPTH];
static i2cblock_t max1236_tx_data[MAX1236_TX_DEPTH];
// ADC results
static uint16_t ch1 = 0, ch2 = 0, ch3 = 0, ch4 = 0;
/* Error trap */
static void i2c_max1236_error_cb(I2CDriver *i2cp, I2CSlaveConfig *i2cscfg){
(void)i2cscfg;
int status = 0;
status = i2cp->id_i2c->SR1;
while(TRUE);
}
/* This callback raise up when transfer finished */
static void i2c_max1236_cb(I2CDriver *i2cp, I2CSlaveConfig *i2cscfg){
(void)*i2cp;
/* get ADC data */
ch1 = ((i2cscfg->rxbuf[0] & 0xF) << 8) + i2cscfg->rxbuf[1];
ch2 = ((i2cscfg->rxbuf[2] & 0xF) << 8) + i2cscfg->rxbuf[3];
ch3 = ((i2cscfg->rxbuf[4] & 0xF) << 8) + i2cscfg->rxbuf[5];
ch4 = ((i2cscfg->rxbuf[6] & 0xF) << 8) + i2cscfg->rxbuf[7];
}
// ADC maxim MAX1236 config
static I2CSlaveConfig max1236 = {
NULL,
i2c_max1236_error_cb,
0,
0,
max1236_rx_data,
max1236_tx_data,
0b0110100,
0,
0,
{NULL},
};
/**
* Initilization routine. See datasheet on page 13 to understand
* how to initialize ADC.
*/
void init_max1236(void){
/* this data we must send via IC to setup ADC */
max1236.rxbytes = 0;
max1236.txbytes = 2; // total 2 bytes to be sent
max1236.txbuf[0] = 0b10000011; // config register content. Consult datasheet
max1236.txbuf[1] = 0b00000111; // config register content. Consult datasheet
// transmit out 2 bytes
i2cAcquireBus(&I2CD2);
i2cMasterTransmit(&I2CD2, &max1236);
while(I2CD2.id_state != I2C_READY){
chThdSleepMilliseconds(1);
}
/* now add pointer to callback function */
max1236.id_callback = i2c_max1236_cb;
i2cReleaseBus(&I2CD2);
}
/* Now simply read 8 bytes to get all 4 ADC channels */
void read_max1236(void){
max1236.txbytes = 0;
max1236.rxbytes = 8;
i2cAcquireBus(&I2CD2);
i2cMasterReceive(&I2CD2, &max1236);
i2cReleaseBus(&I2CD2);
}
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