Prepare for analog measurements

src/measurement.c

@@ -0,0 +1,148 @@
+#include <libopencm3/stm32/adc.h>
+#include <libopencm3/stm32/dma.h>
+
+#include <fxp.h>
+
+#include "pinout.h"
+
+#include "measurement.h"
+
+#define ADC_NUM_CHANNELS 6
+volatile int16_t adc_values[ADC_NUM_CHANNELS];
+
+
+/* Temperature sensor calibration value address */
+#define TEMP110_CAL_ADDR ((uint16_t*) ((uint32_t) 0x1FFFF7C2))
+#define TEMP30_CAL_ADDR ((uint16_t*) ((uint32_t) 0x1FFFF7B8))
+#define VDD_CALIB ((uint16_t) (330)) /* calibration voltage = 3,30V - DO NOT CHANGE */
+#define VDD_APPLI ((uint16_t) (330)) /* actual supply voltage */
+
+/* function for temperature conversion */
+static fxp_t calc_temperature(uint16_t adc_val)
+{
+	fxp_t temperature = FXP_FROM_INT(
+			((int32_t)adc_val * VDD_APPLI / VDD_CALIB) -
+			 (int32_t)*TEMP30_CAL_ADDR);
+
+	temperature = fxp_mult(temperature, FXP_FROM_INT(110 - 30));
+	temperature = fxp_div(temperature, FXP_FROM_INT(*TEMP110_CAL_ADDR - *TEMP30_CAL_ADDR));
+
+	return fxp_add(temperature, FXP_FROM_INT(30));
+}
+
+
+static fxp_t adc_val_to_pin_voltage(uint16_t adc_val)
+{
+	return fxp_div(
+	           fxp_mult(FXP_FROM_INT(adc_val), fxp_div(FXP_FROM_INT(33), FXP_FROM_INT(10))),
+	           FXP_FROM_INT(4096));
+}
+
+
+static fxp_t convert_voltage_divider(uint16_t adc_val, fxp_t r1, fxp_t r2)
+{
+	fxp_t pin_voltage = adc_val_to_pin_voltage(adc_val);
+
+	return fxp_mult(pin_voltage, fxp_div(fxp_add(r1, r2), r2));
+}
+
+
+static fxp_t convert_ina139(uint16_t adc_val, fxp_t rshunt, fxp_t vgain)
+{
+	fxp_t pin_voltage = adc_val_to_pin_voltage(adc_val);
+
+	fxp_t shunt_voltage = fxp_div(pin_voltage, vgain);
+	fxp_t current = fxp_div(shunt_voltage, rshunt);
+
+	return current;
+}
+
+
+void measurement_init(void)
+{
+	uint8_t channels[ADC_NUM_CHANNELS] = {
+		ANALOG_INPUT_U_BAT,   // U_Bat
+		ANALOG_INPUT_U_SOLAR, // U_Solar
+		ANALOG_INPUT_U_SW,    // U_SW
+		ANALOG_INPUT_I_SOLAR, // I_Solar
+		ANALOG_INPUT_I_LOAD,  // I_Load
+		16                    // Temperature sensor
+	};
+
+	adc_power_off(ADC1);
+
+	// enable the temperature sensor
+	adc_enable_temperature_sensor();
+
+	// configure ADC
+	//adc_enable_scan_mode(ADC1);
+	adc_set_single_conversion_mode(ADC1);
+	adc_set_resolution(ADC1, ADC_RESOLUTION_12BIT);
+	adc_set_sample_time_on_all_channels(ADC1, ADC_SMPR_SMP_239DOT5);
+	adc_disable_external_trigger_regular(ADC1);
+	adc_set_right_aligned(ADC1);
+	adc_set_regular_sequence(ADC1, ADC_NUM_CHANNELS, channels);
+
+	// configure DMA for ADC
+
+	//nvic_enable_irq(NVIC_DMA1_STREAM5_IRQ);
+	dma_channel_reset(DMA1, DMA_CHANNEL1);
+	dma_set_priority(DMA1, DMA_CHANNEL1, DMA_CCR_PL_LOW);
+	dma_set_memory_size(DMA1, DMA_CHANNEL1, DMA_CCR_MSIZE_16BIT);
+	dma_set_peripheral_size(DMA1, DMA_CHANNEL1, DMA_CCR_PSIZE_16BIT);
+	dma_enable_memory_increment_mode(DMA1, DMA_CHANNEL1);
+	dma_enable_circular_mode(DMA1, DMA_CHANNEL1);
+	dma_set_read_from_peripheral(DMA1, DMA_CHANNEL1);
+	dma_set_peripheral_address(DMA1, DMA_CHANNEL1, (uint32_t) &ADC1_DR);
+	/* The array adc_values[] is filled with the waveform data to be output */
+	dma_set_memory_address(DMA1, DMA_CHANNEL1, (uint32_t) adc_values);
+	dma_set_number_of_data(DMA1, DMA_CHANNEL1, ADC_NUM_CHANNELS);
+	//dma_enable_transfer_complete_interrupt(DMA1, DMA_CHANNEL1);
+	dma_enable_channel(DMA1, DMA_CHANNEL1);
+
+	adc_enable_dma(ADC1);
+
+	adc_power_on(ADC1);
+}
+
+
+void measurement_start(void)
+{
+	// start the ADC conversion sequency. The result will be transferred to RAM
+	// by the DMA.
+	adc_start_conversion_regular(ADC1);
+}
+
+
+void measurement_wait_for_completion(void)
+{
+	// wait for DMA transfer to complete
+	while(!dma_get_interrupt_flag(DMA1, DMA_CHANNEL1, DMA_TCIF));
+	dma_clear_interrupt_flags(DMA1, DMA_CHANNEL1, DMA_TCIF);
+}
+
+
+void measurement_finalize(struct MeasurementResult *result)
+{
+	result->u_bat = convert_voltage_divider(adc_values[ANALOG_INPUT_U_BAT],
+	                                        FXP_FROM_INT(220),
+	                                        FXP_FROM_INT(22));
+
+	result->u_solar = convert_voltage_divider(adc_values[ANALOG_INPUT_U_SOLAR],
+	                                        FXP_FROM_INT(330),
+	                                        FXP_FROM_INT(22));
+
+	result->u_sw = convert_voltage_divider(adc_values[ANALOG_INPUT_U_SW],
+	                                        FXP_FROM_INT(1000),
+	                                        FXP_FROM_INT(47));
+
+	result->i_solar = convert_ina139(adc_values[ANALOG_INPUT_I_SOLAR],
+	                                 fxp_div(FXP_FROM_INT(2), FXP_FROM_INT(1000)),
+	                                 FXP_FROM_INT(56));
+
+	result->i_load = convert_ina139(adc_values[ANALOG_INPUT_I_LOAD],
+	                                fxp_div(FXP_FROM_INT(5), FXP_FROM_INT(1000)),
+	                                FXP_FROM_INT(56));
+
+	result->temperature = calc_temperature(adc_values[5]);
+}

src/measurement.h

@@ -0,0 +1,21 @@
+#ifndef MEASUREMENT_H
+#define MEASUREMENT_H
+
+#include <fxp_basic.h>
+
+struct MeasurementResult
+{
+	fxp_t u_bat;         // in Volt
+	fxp_t u_solar;       // in Volt
+	fxp_t u_sw;          // in Volt
+	fxp_t i_solar;       // in Ampere
+	fxp_t i_load;        // in Ampere
+	fxp_t temperature;   // in degrees Celsius
+};
+
+void measurement_init(void);
+void measurement_start(void);
+void measurement_wait_for_completion(void);
+void measurement_finalize(struct MeasurementResult *result);
+
+#endif // MEASUREMENT_H

src/pinout.h

@@ -27,4 +27,12 @@
 #define LOAD_SWITCH_PORT     GPIOA
 #define LOAD_SWITCH_PIN      GPIO12
 
+/* Analog channels */
+
+#define ANALOG_INPUT_U_BAT          0
+#define ANALOG_INPUT_U_SOLAR        1
+#define ANALOG_INPUT_U_SW           2
+#define ANALOG_INPUT_I_SOLAR        3
+#define ANALOG_INPUT_I_LOAD         4
+
 #endif // PINOUT_H