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#include "stm32f10x_rcc.h"
#include "adc.h"
#include <stdio.h>
#include <inttypes.h>
/* The ADC input clock is generated from PCLK2/APB2 divided by a prescaler
* and it must not exceed 14MHz.
*
* ADC1 and ADC2 are clocked by APB2
*
* 1) Power on by setting ADON in ADC_CR2
* Conversion starts when ADON is set for a second time after some
* time t > t_stab.
*
* Up to 16 selected conversion must be selected in ADC_SQRx
*
* Single conversion mode:
* Set the ADON bit in the ADC_CR2 register
* Once the conversion is complete:
* Converted data is stored in ADC_DR
* EOC flag is set
* Interrupt is generated if EOCIE is set
*
* Calibration:
* Calibration is started by setting the CAL bit in the ADC_CR2 register.
* Once calibration is over, the CAL bit is reset by hardware and normal
* conversion can be performed. Calibrate at power-on.
*
* ALIGN in ADC_CR2 selects the alignment of data
*
* IMPORTANT: maximum external impedance must be below 0.4kOhms for 1.5
* sample conversion time.
*
* At 55.5 cycles/sample, the external input impedance < 50kOhms*/
void adc_init(void) {
/* PCLK2 is the APB2 clock */
RCC_ADCCLKConfig(RCC_PCLK2_Div6);
/* Enable ADC1 clock so that we can talk to it */
RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC1, ENABLE);
/* Put everything back to power-on defaults */
RCC_APB2PeriphResetCmd(RCC_APB2Periph_ADC1, ENABLE);
RCC_APB2PeriphResetCmd(RCC_APB2Periph_ADC1, DISABLE);
ADC_CR1 = 0;
ADC_CR2 = CR2_EXTSEL_SWSTART | CR2_EXTTRIG; // Software triggers conversions
ADC_SQR1 = 0;
/* Up the sample conversion time to 55.5 cycles/sec, see note above */
ADC_SMPR1 = 0xB6DB6D;
ADC_SMPR2 = 0x2DB6DB6D;
/* Enable the ADC */
CR2_ADON_BIT = 1;
/* Reset the calibration registers and then perform a reset */
CR2_RSTCAL_BIT = 1;
while(CR2_RSTCAL_BIT)
;
CR2_CAL_BIT = 1;
while(CR2_CAL_BIT)
;
}
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