[DNM] samples: basic: fade_led: pwm120_test

pwm120 100% duty cycle bug showcase

Signed-off-by: Piotr Krzyzanowski <[email protected]>

Author: nordic-pikr

samples/basic/fade_led/boards/nrf54h20dk_nrf54h20_cpuapp.overlay

@@ -0,0 +1,47 @@
+/*
+ * Copyright (c) 2024 Nordic Semiconductor ASA
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Test requires wire connection between:
+ *  - PWM120 OUT[0] at P7.0
+ *  - LED[0-4] input at P9.[0-4]
+ */
+
+#include <zephyr/dt-bindings/pwm/pwm.h>
+#include <zephyr/dt-bindings/gpio/gpio.h>
+#include <zephyr/dt-bindings/gpio/nordic-nrf-gpio.h>
+
+&pwm130 {
+	status = "disabled";
+};
+
+&pwm_led2 {
+	// pwms = <&pwm130 0 PWM_MSEC(10) PWM_POLARITY_NORMAL>;
+	pwms = <&pwm120 0 PWM_MSEC(10) PWM_POLARITY_NORMAL>;
+};
+
+&pinctrl {
+	pwm120_default: pwm120_default {
+		group1 {
+			psels = <NRF_PSEL(PWM_OUT0, 7, 0)>;
+		};
+	};
+	pwm120_sleep: pwm120_sleep {
+		group1 {
+			psels = <NRF_PSEL(PWM_OUT0, 7, 0)>;
+			low-power-enable;
+		};
+	};
+};
+
+&pwm120 {
+	status = "okay";
+	pinctrl-0 = <&pwm120_default>;
+	pinctrl-1 = <&pwm120_sleep>;
+	pinctrl-names = "default", "sleep";
+	memory-regions = <&dma_fast_region>;
+};
+
+&dma_fast_region {
+	status = "okay";
+};

samples/basic/fade_led/src/main.c

@@ -16,15 +16,11 @@
 
 static const struct pwm_dt_spec pwm_led0 = PWM_DT_SPEC_GET(DT_ALIAS(pwm_led0));
 
-#define NUM_STEPS	50U
-#define SLEEP_MSEC	25U
 
 int main(void)
 {
-	uint32_t pulse_width = 0U;
-	uint32_t step = pwm_led0.period / NUM_STEPS;
-	uint8_t dir = 1U;
 	int ret;
+	uint32_t pulse_width;
 
 	printk("PWM-based LED fade\n");
 
@@ -35,29 +31,35 @@ int main(void)
 	}
 
 	while (1) {
+		pulse_width = 0;
 		ret = pwm_set_pulse_dt(&pwm_led0, pulse_width);
 		if (ret) {
 			printk("Error %d: failed to set pulse width\n", ret);
 			return 0;
 		}
 		printk("Using pulse width %d%%\n", 100 * pulse_width / pwm_led0.period);
 
-		if (dir) {
-			pulse_width += step;
-			if (pulse_width >= pwm_led0.period) {
-				pulse_width = pwm_led0.period - step;
-				dir = 0U;
-			}
-		} else {
-			if (pulse_width >= step) {
-				pulse_width -= step;
-			} else {
-				pulse_width = step;
-				dir = 1U;
-			}
+		k_msleep(1000);
+
+		pulse_width = pwm_led0.period / 2;
+		ret = pwm_set_pulse_dt(&pwm_led0, pulse_width);
+		if (ret) {
+			printk("Error %d: failed to set pulse width\n", ret);
+			return 0;
+		}
+		printk("Using pulse width %d%%\n", 100 * pulse_width / pwm_led0.period);
+
+		k_msleep(1000);
+
+		pulse_width = pwm_led0.period;
+		ret = pwm_set_pulse_dt(&pwm_led0, pulse_width);
+		if (ret) {
+			printk("Error %d: failed to set pulse width\n", ret);
+			return 0;
 		}
+		printk("Using pulse width %d%%\n", 100 * pulse_width / pwm_led0.period);
 
-		k_sleep(K_MSEC(SLEEP_MSEC));
+		k_msleep(1000);
 	}
 	return 0;
 }