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+/* *****************************************************************************
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Created: 12/18/09 02:34:47
+ * Copyright (c) 2009 Perry L. Hung. All rights reserved.
+ *
+ * ****************************************************************************/
+
+/**
+ * @file adc.c
+ *
+ * @brief Analog to digital converter routines
+ */
+
+#include "libmaple.h"
+#include "rcc.h"
+#include "adc.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) {
+ rcc_set_adc_prescaler(PCLK2_DIV_2);
+ rcc_enable_clk_adc1();
+ rcc_reset_adc1();
+
+ 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 */
+ /* TODO: fix magic numbers */
+ 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)
+ ;
+}
+
+
+void adc_disable(void) {
+ CR2_ADON_BIT = 0;
+}