Driver for AD7705/AD7706 SPI ADC

extras/ad770x/ad770x.h

@@ -0,0 +1,118 @@
+/**
+ * Driver for AD7705/AD7706 SPI ADC
+ *
+ * Part of esp-open-rtos
+ * Copyright (C) 2017 Ruslan V. Uss <unclerus@gmail.com>
+ * BSD Licensed as described in the file LICENSE
+ */
+#ifndef _EXTRAS_AD770X_H_
+#define _EXTRAS_AD770X_H_
+
+#include <stdint.h>
+#include <stdbool.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * Input gain
+ */
+typedef enum
+{
+    AD770X_GAIN_1 = 0,
+    AD770X_GAIN_2,
+    AD770X_GAIN_4,
+    AD770X_GAIN_8,
+    AD770X_GAIN_16,
+    AD770X_GAIN_32,
+    AD770X_GAIN_64,
+    AD770X_GAIN_128
+} ad770x_gain_t;
+
+/**
+ * Master clock frequency
+ */
+typedef enum
+{
+    AD770X_MCLK_1MHz = 0,  //!< 1 MHz
+    AD770X_MCLK_2MHz,      //!< 2 MHz
+    AD770X_MCLK_2_4576MHz, //!< 2.4576 MHz
+    AD770X_MCLK_4_9152MHz, //!< 4.9152 MHz
+} ad770x_master_clock_t;
+
+/**
+ * Output update rate
+ */
+typedef enum
+{
+    AD770X_RATE_20 = 0,  //!< Output update rate is 20 Hz,  -3 dB filter cutoff = 5.24 Hz, works with 1 or 2 MHz master clock
+    AD770X_RATE_25,      //!< Output update rate is 25 Hz,  -3 dB filter cutoff = 6.55 Hz, works with 1 or 2 MHz master clock
+    AD770X_RATE_100,     //!< Output update rate is 100 Hz, -3 dB filter cutoff = 26.2 Hz, works with 1 or 2 MHz master clock
+    AD770X_RATE_200,     //!< Output update rate is 200 Hz, -3 dB filter cutoff = 52.4 Hz, works with 1 or 2 MHz master clock
+    AD770X_RATE_50,      //!< Output update rate is 50 Hz,  -3 dB filter cutoff = 13.1 Hz, works with 2.4576 or 4.9152 MHz master clock
+    AD770X_RATE_60,      //!< Output update rate is 60 Hz,  -3 dB filter cutoff = 15.7 Hz, works with 2.4576 or 4.9152 MHz master clock
+    AD770X_RATE_250,     //!< Output update rate is 250 Hz, -3 dB filter cutoff = 65.5 Hz, works with 2.4576 or 4.9152 MHz master clock
+    AD770X_RATE_500,     //!< Output update rate is 500 Hz, -3 dB filter cutoff = 131 Hz,  works with 2.4576 or 4.9152 MHz master clock
+} ad770x_update_rate_t;
+
+/**
+ * Device mode
+ */
+typedef enum
+{
+    AD770X_MODE_NORMAL = 0,
+    AD770X_MODE_CALIBRATION,
+    AD770X_MODE_ZERO_CALIBRATION,
+    AD770X_MODE_FULL_CALIBRATION
+} ad770x_mode_t;
+
+/**
+ * Device descriptor
+ */
+typedef struct
+{
+    uint8_t cs_pin;                     //!< GPIO pin for chip select
+    ad770x_master_clock_t master_clock; //!< Master clock frequency
+    bool bipolar;                       //!< Bipolar/Unipolar mode
+    ad770x_gain_t gain;                 //!< Input gain
+    ad770x_update_rate_t update_rate;   //!< Output update rate
+} ad770x_params_t;
+
+/**
+ * Init device and setup channel params
+ * @param params Device descriptor pointer
+ * @param channel Input channel
+ * @return Non-zero when error occured
+ */
+int ad770x_init(const ad770x_params_t *params, uint8_t channel);
+
+/**
+ * Set device mode (see datasheet)
+ * @param params Device descriptor pointer
+ * @param channel Input channel
+ * @param mode Device mode
+ */
+void ad770x_set_mode(const ad770x_params_t *params, uint8_t channel, ad770x_mode_t mode);
+
+/**
+ * Get conversion status
+ * @param params Device descriptor pointer
+ * @param channel Input channel
+ * @return true when data is ready
+ */
+bool ad770x_data_ready(const ad770x_params_t *params, uint8_t channel);
+
+/**
+ * Get converted ADC value
+ * @param params Device descriptor pointer
+ * @param channel Input channel
+ * @return Raw ADC value
+ */
+uint16_t ad770x_raw_adc_value(const ad770x_params_t *params, uint8_t channel);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _EXTRAS_AD770X_H_ */