Added a timepulse routine for DFM17 and also a millis() routine. Working toward clock calibration.

src/hal/datatimer.c

@@ -34,8 +34,8 @@ void data_timer_init(uint32_t baud_rate)
 
     NVIC_InitTypeDef nvic_init;
     nvic_init.NVIC_IRQChannel = TIM2_IRQn;
-    nvic_init.NVIC_IRQChannelPreemptionPriority = 0;
-    nvic_init.NVIC_IRQChannelSubPriority = 1;
+    nvic_init.NVIC_IRQChannelPreemptionPriority = 2;
+    nvic_init.NVIC_IRQChannelSubPriority = 2;
     nvic_init.NVIC_IRQChannelCmd = ENABLE;
     NVIC_Init(&nvic_init);
 
@@ -48,8 +48,8 @@ void data_timer_uninit()
 
     NVIC_InitTypeDef nvic_init;
     nvic_init.NVIC_IRQChannel = TIM2_IRQn;
-    nvic_init.NVIC_IRQChannelPreemptionPriority = 0;
-    nvic_init.NVIC_IRQChannelSubPriority = 1;
+    nvic_init.NVIC_IRQChannelPreemptionPriority = 2;
+    nvic_init.NVIC_IRQChannelSubPriority = 2;
     nvic_init.NVIC_IRQChannelCmd = DISABLE;
     NVIC_Init(&nvic_init);
 

src/hal/delay.c

@@ -31,7 +31,7 @@ void delay_init()
 
     NVIC_InitTypeDef nvic_init;
     nvic_init.NVIC_IRQChannel = TIM3_IRQn;
-    nvic_init.NVIC_IRQChannelPreemptionPriority = 0;
+    nvic_init.NVIC_IRQChannelPreemptionPriority = 1;
     nvic_init.NVIC_IRQChannelSubPriority = 1;
     nvic_init.NVIC_IRQChannelCmd = ENABLE;
     NVIC_Init(&nvic_init);

src/hal/millis.c

@@ -0,0 +1,67 @@
+#include <stm32f10x_rcc.h>
+#include <stm32f10x_tim.h>
+#include <misc.h>
+
+#include "src/hal/millis.h"
+
+static uint32_t	millis_counter;
+
+void millis_timer_init(void)
+{
+    TIM_DeInit(TIM7);
+
+    TIM_TimeBaseInitTypeDef tim_init;
+    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM7, ENABLE);
+    RCC_APB2PeriphResetCmd(RCC_APB1Periph_TIM7, DISABLE);
+
+    // The data timer assumes a 24 MHz clock source
+    tim_init.TIM_Prescaler = 24 - 1; // tick every 1/1000000 s
+    tim_init.TIM_CounterMode = TIM_CounterMode_Up;
+    tim_init.TIM_Period = (uint16_t) (1000 - 1);	// Timer pop 1/millisec
+    tim_init.TIM_ClockDivision = TIM_CKD_DIV1;
+    tim_init.TIM_RepetitionCounter = 0;
+
+    TIM_TimeBaseInit(TIM7, &tim_init);
+
+    TIM_ClearITPendingBit(TIM7, TIM_IT_Update);
+    TIM_ITConfig(TIM7, TIM_IT_Update, ENABLE);
+
+    NVIC_InitTypeDef nvic_init;
+    nvic_init.NVIC_IRQChannel = TIM7_IRQn;
+    nvic_init.NVIC_IRQChannelPreemptionPriority = 0;
+    nvic_init.NVIC_IRQChannelSubPriority = 1;
+    nvic_init.NVIC_IRQChannelCmd = ENABLE;
+    NVIC_Init(&nvic_init);
+
+    TIM_Cmd(TIM7, ENABLE);
+}
+
+void millis_timer_uninit()
+{
+    TIM_Cmd(TIM7, DISABLE);
+
+    NVIC_InitTypeDef nvic_init;
+    nvic_init.NVIC_IRQChannel = TIM7_IRQn;
+    nvic_init.NVIC_IRQChannelPreemptionPriority = 0;
+    nvic_init.NVIC_IRQChannelSubPriority = 1;
+    nvic_init.NVIC_IRQChannelCmd = DISABLE;
+    NVIC_Init(&nvic_init);
+
+    TIM_ITConfig(TIM7, TIM_IT_Update, DISABLE);
+    TIM_ClearITPendingBit(TIM7, TIM_IT_Update);
+}
+
+void TIM7_IRQHandler(void)
+{
+    if (TIM_GetITStatus(TIM7, TIM_IT_Update) != RESET) {
+        TIM_ClearITPendingBit(TIM7, TIM_IT_Update);
+
+        millis_counter++;
+
+    }
+}
+
+uint32_t millis(void)
+{
+	return millis_counter;
+}

src/hal/millis.h

@@ -0,0 +1,10 @@
+#ifndef __MILLIS_H
+#define __MILLIS_H
+
+
+extern void millis_timer_init(void);
+extern void millis_timer_uninit();
+
+extern uint32_t millis();
+
+#endif // __MILLIS_H

src/hal/pwm.c

@@ -43,8 +43,8 @@ void pwm_data_timer_init()
 
     NVIC_InitTypeDef nvic_init;
     nvic_init.NVIC_IRQChannel = TIM2_IRQn;
-    nvic_init.NVIC_IRQChannelPreemptionPriority = 0;
-    nvic_init.NVIC_IRQChannelSubPriority = 1;
+    nvic_init.NVIC_IRQChannelPreemptionPriority = 2;
+    nvic_init.NVIC_IRQChannelSubPriority = 2;
     nvic_init.NVIC_IRQChannelCmd = ENABLE;
     NVIC_Init(&nvic_init);
     */
@@ -117,7 +117,7 @@ void pwm_timer_init(uint32_t frequency_hz_100)
 
     NVIC_InitTypeDef nvic_init;
     nvic_init.NVIC_IRQChannel = TIM1_BRK_TIM15_IRQn;
-    nvic_init.NVIC_IRQChannelPreemptionPriority = 0;
+    nvic_init.NVIC_IRQChannelPreemptionPriority = 2;
     nvic_init.NVIC_IRQChannelSubPriority = 1;
     nvic_init.NVIC_IRQChannelCmd = ENABLE;
     NVIC_Init(&nvic_init);
@@ -164,8 +164,8 @@ void pwm_dma_init()
 
     NVIC_InitTypeDef nvic_init;
     nvic_init.NVIC_IRQChannel = DMA1_Channel2_IRQn;
-    nvic_init.NVIC_IRQChannelPreemptionPriority = 0;
-    nvic_init.NVIC_IRQChannelSubPriority = 1;
+    nvic_init.NVIC_IRQChannelPreemptionPriority = 2;
+    nvic_init.NVIC_IRQChannelSubPriority = 0;
     nvic_init.NVIC_IRQChannelCmd = ENABLE;
     NVIC_Init(&nvic_init);
 }
@@ -246,6 +246,7 @@ inline void pwm_timer_set_frequency(uint32_t pwm_period)
     // TIM_CtrlPWMOutputs(TIM15, DISABLE);
     // TIM_Cmd(TIM15, DISABLE);
 
+//    TIM_SetAutoreload(TIM15, pwm_period);
     TIM_SetAutoreload(TIM15, pwm_period);
     // TIM_SetCompare2(TIM15, pwm_period / 2);
 

src/hal/system.c

@@ -360,7 +360,7 @@ void system_init()
     gpio_init();
     dma_adc_init();
     delay_init();
-
+    millis_timer_init();
     system_scheduler_timer_init();
 
     RCC_ClocksTypeDef RCC_Clocks;

src/hal/timepulse.c

@@ -0,0 +1,88 @@
+#include "stm32f10x_exti.h"
+#include "stm32f10x_gpio.h"
+#include "stm32f10x.h"
+#include "stm32f10x_rcc.h"
+#include "misc.h"
+#include "config.h"
+#include "millis.h"
+#include "timepulse.h"
+
+// This define copied from .../src/hal/stm_lib/src/stm32f10x_rcc.c
+#define CR_HSITRIM_Mask           ((uint32_t)0xFFFFFF07)
+
+// Define below pulls the current trim register value out of the Calibration Register (CR)
+// Resulting value will be between 0-31.
+
+#define CURRENT_TRIM	((RCC->CR & ~CR_HSITRIM_Mask) >>3)
+
+/*
+On the DFM-17, PB8 is wired to the GPS Timepulse.  We take advantage of this to do a 
+processor speed calibration.  HSITRIM[4:0] allows for 32 values to adjust the HSI clock
+speed.  The center (16) value is "neutral".  Each trim value above or below 16 adjusts
+the clock by approximately 40kHZ (0.5% of the 8MHZ clock speed) (per AN2868).  0.5% is about 
+5ms per second, so if we detect that we're off by more than 5 millisconds between timepulses, we 
+will suggest a recalibration.  The "calib_suggestion" variable is a static that will be maintained 
+by the timepulse IRQ and can be used at any time it's convenient to adjust the clock speed.
+*/
+
+int calib_suggestion = 16;  // Default, but we will check it in the init routine below.
+uint32_t old_millis = 0;
+volatile int timepulsed = 0;
+volatile uint32_t d_millis = 0;
+
+
+void timepulse_init(void)
+{
+    // Initialize pin PB8 as floating input
+    GPIO_InitTypeDef gpio_init;
+    gpio_init.GPIO_Pin = GPIO_Pin_8;
+    gpio_init.GPIO_Mode = GPIO_Mode_IN_FLOATING;
+    gpio_init.GPIO_Speed = GPIO_Speed_10MHz;
+    GPIO_Init(GPIOB, &gpio_init);
+
+    // PB8 is connected to interrupt line 8, set trigger on the configured edge and enable the interrupt
+    EXTI_InitTypeDef exti_init;
+    exti_init.EXTI_Line = EXTI_Line8;
+    exti_init.EXTI_Mode = EXTI_Mode_Interrupt;
+    exti_init.EXTI_Trigger = EXTI_Trigger_Rising;
+    exti_init.EXTI_LineCmd = ENABLE;
+    EXTI_Init(&exti_init);
+
+    // Attach interrupt line to port B
+    GPIO_EXTILineConfig(GPIO_PortSourceGPIOB, GPIO_PinSource8);
+
+    // PB8 is connected to EXTI_Line8, which has EXTI9_5_IRQn vector. Use priority 0 for now.
+    NVIC_InitTypeDef NVIC_InitStruct;
+    NVIC_InitStruct.NVIC_IRQChannel = EXTI9_5_IRQn;
+    NVIC_InitStruct.NVIC_IRQChannelPreemptionPriority = 0;
+    NVIC_InitStruct.NVIC_IRQChannelSubPriority = 0;
+    NVIC_InitStruct.NVIC_IRQChannelCmd = ENABLE;
+    NVIC_Init(&NVIC_InitStruct);
+
+    // Pull the current calibration to start
+    calib_suggestion = CURRENT_TRIM;		
+}
+
+// This handler is (at present) only being used for the Timepulse interrupt, so we shouldn't need
+// to do additional testing for the cause of the interrupt.
+
+void EXTI9_5_IRQHandler(void)
+{
+    uint32_t	m = millis();
+    int		delta;
+
+    EXTI_ClearITPendingBit(EXTI_Line8);
+    timepulsed++;
+    if (old_millis == 0) {
+       old_millis = m;		// First timepulse.  Just store millis.
+    } else {
+       d_millis = m - old_millis;
+       delta = (int) (m - old_millis - 1000) / 5;	
+       if (((delta + calib_suggestion) >= 0) &&
+           ((delta + calib_suggestion <= 31)) ) {
+          // If the delta makes sense, apply to the suggestion.  Otherwise, skip.
+	  calib_suggestion += delta;
+       }
+       old_millis = m;
+    }
+}

src/hal/timepulse.h

@@ -0,0 +1,9 @@
+#ifndef __TIMEPULSE_H
+#define __TIMEPULSE_H
+
+extern void timepulse_init(void);
+extern int calib_suggestion;
+extern volatile int timepulsed;
+extern volatile uint32_t d_millis;
+
+#endif // __TIMEPULSE_H

src/hal/usart_gps.c

@@ -49,7 +49,7 @@ void usart_gps_init(uint32_t baud_rate, bool enable_irq)
 
     NVIC_InitTypeDef nvic_init;
     nvic_init.NVIC_IRQChannel = USART_IRQ;
-    nvic_init.NVIC_IRQChannelPreemptionPriority = 15;
+    nvic_init.NVIC_IRQChannelPreemptionPriority = 3;
     nvic_init.NVIC_IRQChannelSubPriority = 2;
     nvic_init.NVIC_IRQChannelCmd = ENABLE;
     NVIC_Init(&nvic_init);

src/main.c

@@ -12,6 +12,7 @@
 #include "radio.h"
 #include "config.h"
 #include "log.h"
+#include "hal/timepulse.h"
 
 #ifdef RS41
 #include "hal/i2c.h"
@@ -115,6 +116,17 @@ int main(void)
         goto gps_init;
     }
 
+#ifdef DFM17
+    log_info("Timepulse init\n");
+    timepulse_init();
+    while (1) {
+      if (timepulsed != 0) {
+        log_info("Time Pulse. Calib: %d, Delta: %d\n", calib_suggestion, d_millis);
+        timepulsed = 0;
+      }
+    }
+#endif //DFM17
+
 #if defined(RS41)
     log_info("Si4032 init\n");
     si4032_init();

src/radio_si4063.c

@@ -19,7 +19,7 @@
 
 // TODO: Add support for multiple APRS baud rates
 // This delay is for DFM-17 radiosondes
-#define symbol_delay_bell_202_1200bps_us 820
+#define symbol_delay_bell_202_1200bps_us 821
 
 static volatile bool radio_si4063_state_change = false;
 static volatile uint32_t radio_si4063_freq = 0;