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-rw-r--r--src/lib/adc.h67
1 files changed, 67 insertions, 0 deletions
diff --git a/src/lib/adc.h b/src/lib/adc.h
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--- /dev/null
+++ b/src/lib/adc.h
@@ -0,0 +1,67 @@
+#ifndef _ADC_H_
+#define _ADC_H_
+#include <inttypes.h>
+#include "util.h"
+
+#ifdef __cplusplus
+extern "C"{
+#endif
+
+/* Notes:
+ * The maximum input impedance on each channel MUST be below .4kohms,
+ * or face the wrath of incorrect readings...
+ * This can be changed at the expense of sample time... see datasheet
+ *
+ * Need to up the sample time if otherwise... see datasheet */
+
+/* We'll only use ADC1 for now... */
+#define ADC_BASE 0x40012400
+#define ADC_SR *(volatile uint32_t*)(ADC_BASE + 0)
+#define ADC_CR1 *(volatile uint32_t*)(ADC_BASE + 0x4)
+#define ADC_CR2 *(volatile uint32_t*)(ADC_BASE + 0x8)
+#define ADC_SMPR1 *(volatile uint32_t*)(ADC_BASE + 0xC)
+#define ADC_SMPR2 *(volatile uint32_t*)(ADC_BASE + 0x10)
+#define ADC_SQR1 *(volatile uint32_t*)(ADC_BASE + 0x2C)
+#define ADC_SQR3 *(volatile uint32_t*)(ADC_BASE + 0x34)
+#define ADC_DR *(volatile uint32_t*)(ADC_BASE + 0x4C)
+
+#define CR2_EXTSEL_SWSTART (0xE << 16)
+#define CR2_RSTCAL (BIT(3))
+#define CR2_EXTTRIG (BIT(20))
+
+/* Bit banded bits */
+#define CR2_ADON_BIT *(volatile uint32_t*)(BITBAND_PERI(ADC_BASE+0x8, 0))
+#define CR2_CAL_BIT *(volatile uint32_t*)(BITBAND_PERI(ADC_BASE+0x8, 2))
+#define CR2_RSTCAL_BIT *(volatile uint32_t*)(BITBAND_PERI(ADC_BASE+0x8, 3))
+#define CR2_SWSTART_BIT *(volatile uint32_t*)(BITBAND_PERI(ADC_BASE+0x8 + 2, 6))
+#define SR_EOC_BIT *(volatile uint32_t*)(BITBAND_PERI(ADC_BASE+0, 1))
+
+#define NR_ANALOG_PINS 16
+
+/* Initialize ADC1 to do one-shot conversions */
+void adc_init(void);
+
+/* Perform a single conversion on ADC[0-16],
+ * PRECONDITIONS:
+ * adc initialized */
+static inline int adc_read(int channel) {
+ /* Set channel */
+ ADC_SQR3 = channel;
+
+ /* Start the conversion */
+ CR2_SWSTART_BIT = 1;
+
+ /* Wait for it to finish */
+ while(SR_EOC_BIT == 0)
+ ;
+
+ return ADC_DR;
+}
+
+
+
+#ifdef __cplusplus
+} // extern "C"
+#endif
+#endif
+