Add my_adc/

apps/my_adc/CMakeLists.txt

@@ -0,0 +1,10 @@
+cmake_minimum_required(VERSION 3.20.0)
+
+# Locate the Zephyr build system as a CMake package
+find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
+
+# Project name
+project(my_adc)
+
+# Add source files belong to this application
+target_sources(app PRIVATE src/main.c)

apps/my_adc/boards/nucleo_f767zi.overlay

@@ -0,0 +1,24 @@
+#include <zephyr/dt-bindings/adc/adc.h>
+
+&adc1 {
+    pinctrl-0 = <&adc1_in3_pa3>;
+    pinctrl-names = "default";
+    status = "okay";
+    st,adc-prescaler = <4>;
+    #address-cells = <1>;
+    #size-cells = <0>;
+
+    channel@3 {
+        reg = <3>;
+        zephyr,gain = "ADC_GAIN_1";
+        zephyr,reference = "ADC_REF_INTERNAL";
+        zephyr,acquisition-time = <ADC_ACQ_TIME_DEFAULT>;
+        zephyr,resolution = <12>;
+    };
+};
+
+/ {
+    aliases {
+        myadc = &adc1;
+    };
+};

apps/my_adc/boards/stm32f4_disco.overlay

@@ -0,0 +1,30 @@
+#include <zephyr/dt-bindings/adc/adc.h>
+
+/* PA3 is used by ADC1 channel 3, so keep USART2 as a TX-only console. 
+&usart2 {
+	pinctrl-0 = <&usart2_tx_pa2>;
+	pinctrl-names = "default";
+};*/
+
+&adc1 {
+	pinctrl-0 = <&adc1_in3_pa3>;
+	pinctrl-names = "default";
+	status = "okay";
+	st,adc-prescaler = <4>;
+	#address-cells = <1>;
+	#size-cells = <0>;
+
+	channel@3 {
+		reg = <3>;
+		zephyr,gain = "ADC_GAIN_1";
+		zephyr,reference = "ADC_REF_INTERNAL";
+		zephyr,acquisition-time = <ADC_ACQ_TIME_DEFAULT>;
+		zephyr,resolution = <12>;
+	};
+};
+
+/ {
+	aliases {
+		myadc = &adc1;
+	};
+};

apps/my_adc/prj.conf

@@ -0,0 +1,6 @@
+CONFIG_GPIO=y
+CONFIG_SERIAL=y
+CONFIG_ADC=y
+CONFIG_UART_INTERRUPT_DRIVEN=y
+CONFIG_CONSOLE=y
+CONFIG_PRINTK=y

apps/my_adc/src/main.c

@@ -0,0 +1,75 @@
+#include <inttypes.h>
+#include <stdint.h>
+
+#include <zephyr/kernel.h>
+#include <zephyr/device.h>
+#include <zephyr/drivers/adc.h>
+#include <zephyr/sys/printk.h>
+
+#define MY_ADC_NODE       DT_ALIAS(myadc)
+#define MY_ADC_CH_NODE    DT_CHILD(MY_ADC_NODE, channel_3)
+#define MY_ADC_CHANNEL_ID DT_REG_ADDR(MY_ADC_CH_NODE)
+
+static const struct device *const adc_dev = 
+	DEVICE_DT_GET(MY_ADC_NODE);
+
+static const struct adc_channel_cfg ch_cfg =
+	ADC_CHANNEL_CFG_DT(MY_ADC_CH_NODE);
+
+static uint16_t sample;
+
+static struct adc_sequence seq = {
+	.channels = BIT(MY_ADC_CHANNEL_ID),
+	.buffer = &sample,
+	.buffer_size = sizeof(sample),
+	.resolution = DT_PROP_OR(MY_ADC_CH_NODE, zephyr_resolution, 12),
+};
+
+int main(void) {
+
+	int err;
+
+	if (!device_is_ready(adc_dev)) {
+		printk("ADC device not ready\n");
+		return 0;
+	}
+
+	err = adc_channel_setup(adc_dev, &ch_cfg);
+	if (err < 0) {
+		printk("Could not setup ADC channel (%d)\n", err);
+		return 0;
+	}
+
+	printk("Reading ADC1 channel 3 on PA3 (Arduino A0)\n");
+
+	while (1) {
+		int32_t val_mv;
+		sample = 0;
+
+		err = adc_read(adc_dev, &seq);
+		if (err < 0) {
+			printk("Could not read ADC (%d)\n", err);
+			k_sleep(K_MSEC(500));
+			continue;
+		}
+
+		if (ch_cfg.differential) {
+			val_mv = (int32_t)((int16_t)sample);
+		} else {
+			val_mv = (int32_t)sample;
+		}
+
+		printk("ADC raw: %" PRId32, val_mv);
+		err = adc_raw_to_millivolts(adc_ref_internal(adc_dev), ch_cfg.gain,
+									seq.resolution, &val_mv);
+		if (err < 0) {
+			printk(" (voltage conversion not available)\n");
+		} else {
+			printk(" Voltage: %" PRId32 " mV\n", val_mv);
+		}
+
+		k_sleep(K_MSEC(500));
+	}
+
+	return 0;
+}