A hacky fix for PWM + TWI

code/b-parasite/config/sdk_config.h

@@ -2835,7 +2835,7 @@
 // <e> NRFX_PWM_CONFIG_LOG_ENABLED - Enables logging in the module.
 //==========================================================
 #ifndef NRFX_PWM_CONFIG_LOG_ENABLED
-#define NRFX_PWM_CONFIG_LOG_ENABLED 0
+#define NRFX_PWM_CONFIG_LOG_ENABLED 1
 #endif
 // <o> NRFX_PWM_CONFIG_LOG_LEVEL  - Default Severity level
 
@@ -2846,7 +2846,7 @@
 // <4=> Debug
 
 #ifndef NRFX_PWM_CONFIG_LOG_LEVEL
-#define NRFX_PWM_CONFIG_LOG_LEVEL 3
+#define NRFX_PWM_CONFIG_LOG_LEVEL 4
 #endif
 
 // <o> NRFX_PWM_CONFIG_INFO_COLOR  - ANSI escape code prefix.
@@ -4351,7 +4351,7 @@
 // <4=> Debug
 
 #ifndef NRFX_TWI_CONFIG_LOG_LEVEL
-#define NRFX_TWI_CONFIG_LOG_LEVEL 3
+#define NRFX_TWI_CONFIG_LOG_LEVEL 4
 #endif
 
 // <o> NRFX_TWI_CONFIG_INFO_COLOR  - ANSI escape code prefix.
@@ -8650,7 +8650,7 @@
 // <4=> Debug
 
 #ifndef RTC_CONFIG_LOG_LEVEL
-#define RTC_CONFIG_LOG_LEVEL 4
+#define RTC_CONFIG_LOG_LEVEL 3
 #endif
 
 // <o> RTC_CONFIG_INFO_COLOR  - ANSI escape code prefix.
@@ -8956,7 +8956,7 @@
 // <4=> Debug
 
 #ifndef TWI_CONFIG_LOG_LEVEL
-#define TWI_CONFIG_LOG_LEVEL 3
+#define TWI_CONFIG_LOG_LEVEL 4
 #endif
 
 // <o> TWI_CONFIG_INFO_COLOR  - ANSI escape code prefix.

code/b-parasite/src/main.c

@@ -23,9 +23,9 @@
 
 #define DEAD_BEEF 0xDEADBEEF
 
-void assert_nrf_callback(uint16_t line_num, const uint8_t *p_file_name) {
+// void assert_nrf_callback(uint16_t line_num, const uint8_t *p_file_name) {
-  app_error_handler(DEAD_BEEF, line_num, p_file_name);
+//   app_error_handler(DEAD_BEEF, line_num, p_file_name);
-}
+// }
 
 static void log_init(void) {
   ret_code_t err_code = NRF_LOG_INIT(NULL);
@@ -55,20 +55,28 @@ static void power_manage(void) {
 }
 
 static uint8_t data;
+
+// Here we need to be extra careful with what operations we do. This callback
+// has to return fast-ish, otherwise we hit some hard exceptions.
 static void rtc_callback() {
   NRF_LOG_INFO("rtc callback running...\n");
   NRF_LOG_FLUSH();
   nrf_gpio_pin_set(PRST_LED_PIN);
+  prst_shtc3_read_t temp_humi = prst_shtc3_read();
+  NRF_LOG_INFO("Read temp: " NRF_LOG_FLOAT_MARKER " oC",
+               NRF_LOG_FLOAT(temp_humi.temp_c));
   prst_pwm_init();
   prst_pwm_start();
   // TODO: ADC.
   nrf_delay_ms(500);
+  // TODO: PWM pin seems to be stuch on high after stop.
   prst_pwm_stop();
   prst_ble_update_adv_data(++data);
   prst_adv_start();
   nrf_delay_ms(300);
   prst_adv_stop();
   nrf_gpio_pin_clear(PRST_LED_PIN);
+  NRF_LOG_FLUSH();
 }
 
 int main(void) {
@@ -76,12 +84,9 @@ int main(void) {
   leds_init();
   power_management_init();
   prst_ble_init();
-
+  prst_shtc3_init();
-  prst_sht3c_init();
   prst_rtc_set_callback(rtc_callback);
-  NRF_LOG_FLUSH();
+  prst_rtc_init();
-  // UNUSED_VARIABLE(prst_rtc_init());
-  UNUSED_VARIABLE(prst_rtc_init));
 
   for (;;) {
     power_manage();

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

@@ -16,11 +16,13 @@
 // 50% below with PRST_PWM_FLIP_AT_COUNT to be half the max count.
 #define PRST_PWM_MAX_COUNT 16
 // We will toggle the PWM output when we reach this count.
-#define PRST_PWM_FLIP_AT_COUNT PRST_PWM_MAX_COUNT / 2
+// #define PRST_PWM_FLIP_AT_COUNT PRST_PWM_MAX_COUNT / 2
+#define PRST_PWM_FLIP_AT_COUNT 8
 
 static nrf_drv_pwm_t m_pwm0 = NRF_DRV_PWM_INSTANCE(0);
 
 static nrf_pwm_values_common_t seq_values_[] = {PRST_PWM_FLIP_AT_COUNT};
+
 static const nrf_pwm_sequence_t seq_ = {
     .values.p_common = seq_values_,
     .length = NRF_PWM_VALUES_LENGTH(seq_values_),
@@ -28,19 +30,25 @@ static const nrf_pwm_sequence_t seq_ = {
     .end_delay = 0};
 
 void prst_pwm_init() {
+  // We set the PWM pin as output so we can control its state after the PWM is
+  // stopped. Without this, I'm seeing the PWM pin remaining high after stopped.
+  nrf_gpio_pin_dir_set(PRST_PWM_PIN, NRF_GPIO_PIN_DIR_OUTPUT);
+
   nrf_drv_pwm_config_t const config0 = {
+      // We have to specify the state of the 4 channels. We only care about the
+      // first one, so we set all others to not used.
       .output_pins =
           {
-              PRST_PWM_PIN | NRF_DRV_PWM_PIN_INVERTED,  // channel 0
+              PRST_PWM_PIN | NRF_DRV_PWM_PIN_INVERTED,
-              NRF_DRV_PWM_PIN_NOT_USED,                 // channel 1
+              NRF_DRV_PWM_PIN_NOT_USED,
-              NRF_DRV_PWM_PIN_NOT_USED,                 // channel 2
+              NRF_DRV_PWM_PIN_NOT_USED,
-              NRF_DRV_PWM_PIN_NOT_USED,                 // channel 3
+              NRF_DRV_PWM_PIN_NOT_USED,
           },
       .irq_priority = APP_IRQ_PRIORITY_LOWEST,
-      // This is the hal PRESCALER.
+      // This is the hal PRESCALER
       .base_clock = NRF_PWM_CLK_16MHz,
-      // This is the hal COUNTERTOP.
       .count_mode = NRF_PWM_MODE_UP_AND_DOWN,
+      // This is the hal COUNTERTOP.
       .top_value = PRST_PWM_MAX_COUNT,
       .load_mode = NRF_PWM_LOAD_COMMON,
       .step_mode = NRF_PWM_STEP_AUTO};
@@ -48,12 +56,16 @@ void prst_pwm_init() {
 }
 
 void prst_pwm_start() {
-  // Loop forever.
+  // Loop until stopped.
   APP_ERROR_CHECK(
       nrf_drv_pwm_simple_playback(&m_pwm0, &seq_, 1, NRF_DRV_PWM_FLAG_LOOP));
 }
 
 void prst_pwm_stop() {
-  APP_ERROR_CHECK(nrf_drv_pwm_stop(&m_pwm0, /*wait_until_stopped=*/true));
+  // Careful when using wait_until_stopped! When calling this from within the
+  // RTC callback, somtimes I'm hitting a hard exception. I haven't figured it
+  // out yet, but probably some race condition for waiting + rtc?
+  APP_ERROR_CHECK(nrf_drv_pwm_stop(&m_pwm0, /*wait_until_stopped=*/false));
   nrf_drv_pwm_uninit(&m_pwm0);
+  nrf_gpio_pin_clear(PRST_PWM_PIN);
 }

code/b-parasite/src/prst/shtc3.c

@@ -5,44 +5,60 @@
 #include <nrf_drv_twi.h>
 #include <nrf_gpio.h>
 #include <nrf_log.h>
+#include <nrf_log_ctrl.h>
 
 // #define PRST_SHT3C_DEFAULT_ADDR 0x70
+// I'm using a sht30 to test while I wait for the new PCBs.
 #define PRST_SHT3C_DEFAULT_ADDR 0x44
 
 static const nrf_drv_twi_t twi_ = NRF_DRV_TWI_INSTANCE(0);
+static nrf_drv_twi_config_t twi_config_ = NRF_DRV_TWI_DEFAULT_CONFIG;
 
 static uint8_t buff[6];
-static uint8_t tx_data[] = {0x2c, 0x06};
 
-void prst_sht3c_init() {
+void prst_shtc3_init() {
-  nrf_drv_twi_config_t twi_config = NRF_DRV_TWI_DEFAULT_CONFIG;
+  twi_config_.scl = NRF_GPIO_PIN_MAP(0, 3);
-  twi_config.scl = NRF_GPIO_PIN_MAP(0, 3);
+  twi_config_.sda = NRF_GPIO_PIN_MAP(0, 2);
-  twi_config.sda = NRF_GPIO_PIN_MAP(0, 28);
   // twi_config.clear_bus_init = true;
-  twi_config.frequency = NRF_TWI_FREQ_400K;
+  twi_config_.frequency = NRF_TWI_FREQ_100K;
+}
 
+prst_shtc3_read_t prst_shtc3_read() {
   uint32_t err_code;
+  // Sends request for data with clock stretching. Currently not working
+  // very well - sometimes it works, sometimes the read blocks forever.
   // uint8_t tx_data[] = {0x2c, 0x06};
-  err_code = nrf_drv_twi_init(&twi_, &twi_config, NULL, NULL);
+  // Request for data withour clock stretching. If no data is available yet,
+  // the result will be a NACK.
+  uint8_t tx_data[] = {0x24, 0x00};
+
+  err_code = nrf_drv_twi_init(&twi_, &twi_config_, NULL, NULL);
+
   APP_ERROR_CHECK(err_code);
+  nrf_delay_ms(10);
   nrf_drv_twi_enable(&twi_);
   nrf_delay_ms(10);
   err_code = nrf_drv_twi_tx(&twi_, PRST_SHT3C_DEFAULT_ADDR, tx_data,
-                            sizeof(tx_data), true);
+                            sizeof(tx_data), false);
   APP_ERROR_CHECK(err_code);
 
-  nrf_delay_ms(10);
+  // TODO(rbaron): timeout.
-
+  while (true) {
-  NRF_LOG_INFO("WILL READ DATA:");
+    err_code = nrf_drv_twi_rx(&twi_, PRST_SHT3C_DEFAULT_ADDR, buff, 6);
-  err_code = nrf_drv_twi_rx(&twi_, PRST_SHT3C_DEFAULT_ADDR, buff, 6);
+    if (err_code == NRF_ERROR_DRV_TWI_ERR_ANACK) {
-  NRF_LOG_INFO("OH NO!");
+      nrf_delay_ms(10);
-  APP_ERROR_CHECK(err_code);
+      continue;
-
+    }
-  NRF_LOG_INFO("READ DATA: \n");
+    break;
-  for (int i = 0; i < 6; i++) {
-    NRF_LOG_INFO("0x%d ", buff[i]);
   }
-  NRF_LOG_INFO("Okay. \n");
-}
 
-void prst_sht3c_read();
+  // TODO(rbaron): put the sensor to sleep & save power.
+
+  nrf_drv_twi_uninit(&twi_);
+  NRF_LOG_INFO("Computing...");
+  double temp_c =
+      -45 + 175 * ((double)((buff[0] << 8) | buff[1])) / ((1 << 16) - 1);
+  // double humi = 100 * ( (double) ((buff[0] << 8) | buff[1])) / ((1<<16) - 1);
+  prst_shtc3_read_t ret = {.temp_c = temp_c, .humidity = 0};
+  return ret;
+}

code/b-parasite/src/prst/shtc3.h

@@ -1,10 +1,12 @@
 #ifndef _PRST_SHT3C_H_
 #define _PRST_SHT3C_H_
 
-typedef struct prst_sht3c_read {
+typedef struct prst_shtc3_values {
-} prst_sh3c_read_t;
+  double temp_c;
+  double humidity;
+} prst_shtc3_read_t;
 
-void prst_sht3c_init();
+void prst_shtc3_init();
-void prst_sht3c_read();
+prst_shtc3_read_t prst_shtc3_read();
 
 #endif  // _PRST_SHT3C_H_

resources.md

@@ -425,4 +425,7 @@ Comparison table form Sensirion: [link](https://www.sensirion.com/en/environment
   * ~ $1.5 each
   * Google JLC support for assembly [link](https://jlcpcb.com/parts/componentSearch?searchTxt=sht30)
   * 0.3uA in sleep
-  * KiCad footprint on [GitHub](https://kicad.github.io/symbols/Sensor_Humidity)
+  * KiCad footprint on [GitHub](https://kicad.github.io/symbols/Sensor_Humidity)
+
+# Antenna
+* Guide for PCB design on [devzone](https://devzone.nordicsemi.com/nordic/short-range-guides/b/hardware-and-layout/posts/general-pcb-design-guidelines-for-nrf52)