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diff --git a/libmaple/adc.c b/libmaple/adc.c
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+/******************************************************************************
+ * The MIT License
+ *
+ * Copyright (c) 2010 Perry Hung.
+ * Copyright (c) 2011, 2012 LeafLabs, LLC.
+ *
+ * Permission is hereby granted, free of charge, to any person
+ * obtaining a copy of this software and associated documentation
+ * files (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy,
+ * modify, merge, publish, distribute, sublicense, and/or sell copies
+ * of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *****************************************************************************/
+
+/**
+ * @file libmaple/adc.c
+ * @author Marti Bolivar <mbolivar@leaflabs.com>,
+ *         Perry Hung <perry@leaflabs.com>
+ * @brief Analog to digital converter routines
+ */
+
+#include <libmaple/adc.h>
+#include <libmaple/libmaple.h>
+#include <libmaple/rcc.h>
+
+/**
+ * @brief Initialize an ADC peripheral.
+ *
+ * Initializes the RCC clock line for the given peripheral.  Resets
+ * ADC device registers.
+ *
+ * @param dev ADC peripheral to initialize
+ */
+void adc_init(const adc_dev *dev) {
+    rcc_clk_enable(dev->clk_id);
+    rcc_reset_dev(dev->clk_id);
+}
+
+/**
+ * @brief Set external event select for regular group
+ * @param dev ADC device
+ * @param event Event used to trigger the start of conversion.
+ * @see adc_extsel_event
+ */
+void adc_set_extsel(const adc_dev *dev, adc_extsel_event event) {
+    uint32 cr2 = dev->regs->CR2;
+    cr2 &= ~ADC_CR2_EXTSEL;
+    cr2 |= event;
+    dev->regs->CR2 = cr2;
+}
+
+/**
+ * @brief Set the sample rate for all channels on an ADC device.
+ *
+ * Don't call this during conversion.
+ *
+ * @param dev adc device
+ * @param smp_rate sample rate to set
+ * @see adc_smp_rate
+ */
+void adc_set_sample_rate(const adc_dev *dev, adc_smp_rate smp_rate) {
+    uint32 adc_smpr1_val = 0, adc_smpr2_val = 0;
+    int i;
+
+    for (i = 0; i < 10; i++) {
+        if (i < 8) {
+            /* ADC_SMPR1 determines sample time for channels [10,17] */
+            adc_smpr1_val |= smp_rate << (i * 3);
+        }
+        /* ADC_SMPR2 determines sample time for channels [0,9] */
+        adc_smpr2_val |= smp_rate << (i * 3);
+    }
+
+    dev->regs->SMPR1 = adc_smpr1_val;
+    dev->regs->SMPR2 = adc_smpr2_val;
+}
+
+/**
+ * @brief Perform a single synchronous software triggered conversion on a
+ *        channel.
+ * @param dev ADC device to use for reading.
+ * @param channel channel to convert
+ * @return conversion result
+ */
+uint16 adc_read(const adc_dev *dev, uint8 channel) {
+    adc_reg_map *regs = dev->regs;
+
+    adc_set_reg_seqlen(dev, 1);
+
+    regs->SQR3 = channel;
+    regs->CR2 |= ADC_CR2_SWSTART;
+    while (!(regs->SR & ADC_SR_EOC))
+        ;
+
+    return (uint16)(regs->DR & ADC_DR_DATA);
+}