Hard coded PWM with 500kHz frequency works

code/b-parasite/Makefile

@@ -48,6 +48,7 @@ SRC_FILES += \
   $(SDK_ROOT)/modules/nrfx/drivers/src/nrfx_gpiote.c \
   $(SDK_ROOT)/modules/nrfx/drivers/src/nrfx_rtc.c \
   $(SDK_ROOT)/modules/nrfx/drivers/src/prs/nrfx_prs.c \
+  $(SDK_ROOT)/modules/nrfx/drivers/src/nrfx_pwm.c \
   $(SDK_ROOT)/modules/nrfx/drivers/src/nrfx_uart.c \
   $(SDK_ROOT)/modules/nrfx/drivers/src/nrfx_uarte.c \
   $(SDK_ROOT)/components/libraries/bsp/bsp.c \
@@ -62,6 +63,7 @@ SRC_FILES += \
   $(SDK_ROOT)/components/softdevice/common/nrf_sdh_ble.c \
   $(SDK_ROOT)/components/softdevice/common/nrf_sdh_soc.c \
 	$(PROJ_DIR)/prst/ble.c \
+	$(PROJ_DIR)/prst/pwm.c \
 	$(PROJ_DIR)/prst/rtc.c \
 
 # Include folders common to all targets

code/b-parasite/config/prst_config.h

@@ -1,10 +1,16 @@
 #ifndef _PRST_CONFIG_H_
 #define _PRST_CONFIG_H_
 
+#include "nrf_gpio.h"
+
 // Deep sleep.
 #define PRST_DEEP_SLEEP_IN_SECONDS 2
 
 // BLE.
 #define PRST_BLE_ADV_NAME "Prst"
 
+// PWM.
+#define PRST_PWM_PIN NRF_GPIO_PIN_MAP(0, 29)
+#define PRST_PWM_FREQUENCY 500000
+
 #endif  // _PRST_CONFIG_H_

code/b-parasite/config/sdk_config.h

@@ -2710,13 +2710,13 @@
 // <e> NRFX_PWM_ENABLED - nrfx_pwm - PWM peripheral driver
 //==========================================================
 #ifndef NRFX_PWM_ENABLED
-#define NRFX_PWM_ENABLED 0
+#define NRFX_PWM_ENABLED 1
 #endif
 // <q> NRFX_PWM0_ENABLED  - Enable PWM0 instance
 
 
 #ifndef NRFX_PWM0_ENABLED
-#define NRFX_PWM0_ENABLED 0
+#define NRFX_PWM0_ENABLED 1
 #endif
 
 // <q> NRFX_PWM1_ENABLED  - Enable PWM1 instance
@@ -4949,7 +4949,7 @@
 // <e> PWM_ENABLED - nrf_drv_pwm - PWM peripheral driver - legacy layer
 //==========================================================
 #ifndef PWM_ENABLED
-#define PWM_ENABLED 0
+#define PWM_ENABLED 1
 #endif
 // <o> PWM_DEFAULT_CONFIG_OUT0_PIN - Out0 pin  <0-31>
 
@@ -5049,7 +5049,7 @@
 
 
 #ifndef PWM0_ENABLED
-#define PWM0_ENABLED 0
+#define PWM0_ENABLED 1
 #endif
 
 // <q> PWM1_ENABLED  - Enable PWM1 instance

code/b-parasite/src/main.c

@@ -16,6 +16,7 @@
 #include "nrf_sdh_ble.h"
 #include "nrf_soc.h"
 #include "prst/ble.h"
+#include "prst/pwm.h"
 #include "prst/rtc.h"
 
 // P0.03
@@ -79,6 +80,8 @@ int main(void) {
   log_init();
   leds_init();
   power_management_init();
+  prst_pwm_init();
+  prst_pwm_start();
   prst_ble_init();
 
   prst_rtc_set_callback(rtc_callback);

code/b-parasite/src/prst/ble.c

@@ -58,9 +58,6 @@ static uint8_t adv_handle_ = BLE_GAP_ADV_SET_HANDLE_NOT_SET;
 static ble_gap_adv_params_t adv_params_;
 
 static void init_advertisement_data() {
-  UNUSED_VARIABLE(adv_data_);
-  UNUSED_VARIABLE(advdata_service_data_);
-
   // We'll just broadcast our data, so we disallow connections and scan
   // requests.
   adv_params_.properties.type =

code/b-parasite/src/prst/pwm.c

@@ -0,0 +1,50 @@
+#include "prst/pwm.h"
+
+#include <app_error.h>
+#include <nordic_common.h>
+#include <nrf_drv_pwm.h>
+#include <nrf_log.h>
+#include <nrf_pwm.h>
+
+#include "prst_config.h"
+
+#define PRST_PWM_BASE_FREQ NRF_PWM_CLK_16MHz
+
+static nrf_drv_pwm_t m_pwm0 = NRF_DRV_PWM_INSTANCE(0);
+
+static nrf_pwm_values_common_t seq_values_[] = {8};
+static const nrf_pwm_sequence_t seq_ = {
+    .values.p_common = seq_values_,
+    .length = NRF_PWM_VALUES_LENGTH(seq_values_),
+    .repeats = 0,
+    .end_delay = 0};
+
+void prst_pwm_init() {
+  UNUSED_VARIABLE(seq_);
+
+  nrf_drv_pwm_config_t const config0 = {
+      .output_pins =
+          {
+              PRST_PWM_PIN | NRF_DRV_PWM_PIN_INVERTED,  // channel 0
+              NRF_DRV_PWM_PIN_NOT_USED,                 // channel 1
+              NRF_DRV_PWM_PIN_NOT_USED,                 // channel 2
+              NRF_DRV_PWM_PIN_NOT_USED,                 // channel 3
+          },
+      .irq_priority = APP_IRQ_PRIORITY_LOWEST,
+      // This is the hal PRESCALER.
+      .base_clock = NRF_PWM_CLK_16MHz,
+      // This is the hal COUNTERTOP.
+      .count_mode = NRF_PWM_MODE_UP_AND_DOWN,
+      // .top_value = (uint16_t)(1e16 / PRST_PWM_FREQUENCY),
+      .top_value = 16,
+      .load_mode = NRF_PWM_LOAD_COMMON,
+      .step_mode = NRF_PWM_STEP_AUTO};
+  APP_ERROR_CHECK(nrf_drv_pwm_init(&m_pwm0, &config0, NULL));
+}
+
+void prst_pwm_start() {
+  APP_ERROR_CHECK(
+      nrf_drv_pwm_simple_playback(&m_pwm0, &seq_, 1, NRF_DRV_PWM_FLAG_LOOP));
+}
+
+void prst_pwm_stop() {}

code/b-parasite/src/prst/pwm.h

@@ -0,0 +1,10 @@
+#ifndef _PRST_PWM_H_
+#define _PRST_PWM_H_
+
+void prst_pwm_init();
+
+void prst_pwm_start();
+
+void prst_pwm_stop();
+
+#endif  // _PRST_PWM_H_