Set DFM17 clocks correctly to 24 MHz

src/config.h

@@ -8,6 +8,11 @@
 // Comment the following error to make the DFM17 development branch compile :)
 #error "DFM17 radiosonde support is a work in progress. This code does not work yet!"
 
+#if !defined(RS41) && !defined(DFM17)
+#error "No hardware type specified. Please define RS41 or DFM17."
+#endif
+
+
 // Enable semihosting to receive debug logs during development
 // See the README for details on how to set up debugging and debug logs with GDB
 // NOTE: Semihosting has to be disabled when the RS41 radiosonde is not connected to an STM32 programmer dongle, otherwise the firmware will not run.

src/hal/datatimer.c

@@ -19,6 +19,7 @@ void data_timer_init(uint32_t baud_rate)
     RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);
     RCC_APB2PeriphResetCmd(RCC_APB1Periph_TIM2, 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) ((1000000 / baud_rate) - 1);

src/hal/delay.c

@@ -18,6 +18,7 @@ void delay_init()
     RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);
     RCC_APB1PeriphResetCmd(RCC_APB1Periph_TIM3, DISABLE);
 
+    // The delay timer assumes a 24 MHz clock source
     tim_init.TIM_Prescaler = 24 - 1;
     tim_init.TIM_CounterMode = TIM_CounterMode_Up;
     tim_init.TIM_Period = 0;

src/hal/spi.c

@@ -52,7 +52,7 @@ void spi_init()
 #endif
 #ifdef DFM17
     // TODO: Adjust SPI speed correctly, not sure what this should be
-    spi_init.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_64;
+    spi_init.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_32;
 #endif
     spi_init.SPI_FirstBit = SPI_FirstBit_MSB;
 #ifdef RS41

src/hal/system.c

@@ -40,7 +40,7 @@ static void rcc_init()
 {
     RCC_DeInit();
 #ifdef RS41
-    // The RS41 hardware uses an external clock
+    // The RS41 hardware uses an external clock at 24 MHz
     RCC_HSEConfig(RCC_HSE_ON);
 
     ErrorStatus hse_status = RCC_WaitForHSEStartUp();
@@ -52,9 +52,11 @@ static void rcc_init()
 #ifdef DFM17
     // The DFM17 hardware uses the internal clock
     RCC_AdjustHSICalibrationValue(0x10U);
-    RCC_PLLConfig(RCC_PLLSource_HSI_Div2, RCC_PLLMul_4);
+    // Set up a 24 MHz PLL for 24 MHz SYSCLK (8 MHz / 2) * 6 = 24 MHz
+    RCC_PLLConfig(RCC_PLLSource_HSI_Div2, RCC_PLLMul_6);
     RCC_HSICmd(ENABLE);
     RCC_PLLCmd(ENABLE);
+    while (RCC_GetFlagStatus(RCC_FLAG_PLLRDY) == RESET);
 #endif
 
     //SystemInit();
@@ -64,15 +66,17 @@ static void rcc_init()
 
     // TODO: Check what the delay timer TIM3 settings really should be and WTF the clock tick really is!?!?!?
 
-    RCC_HCLKConfig(RCC_SYSCLK_Div1); // Was: RCC_SYSCLK_Div4
-    RCC_PCLK2Config(RCC_HCLK_Div1); // Was: 4
-    RCC_PCLK1Config(RCC_HCLK_Div1); // Was: 2
+    RCC_HCLKConfig(RCC_SYSCLK_Div1);
+    RCC_PCLK2Config(RCC_HCLK_Div1);
+    RCC_PCLK1Config(RCC_HCLK_Div1);
 #ifdef RS41
+    // Use the 24 MHz external clock as SYSCLK
     RCC_SYSCLKConfig(RCC_SYSCLKSource_HSE);
 
     while (RCC_GetSYSCLKSource() != 0x04);
 #endif
 #ifdef DFM17
+    // Use the 24 MHz PLL as SYSCLK
     RCC_SYSCLKConfig(RCC_SYSCLKSource_PLLCLK);
 
     while (RCC_GetSYSCLKSource() != 0x08);

src/main.c

@@ -96,11 +96,11 @@ int main(void)
         log_info("Pulse counter init\n");
         pulse_counter_init(PULSE_COUNTER_PIN_MODE, PULSE_COUNTER_INTERRUPT_EDGE);
     } else {
-        log_info("I2C init: clock speed %d kHz\n", I2C_BUS_CLOCK_SPEED / 1000);
 #ifdef RS41
-        // dfm17 does not use i2c
+        // Only RS41 uses the I2C bus
+        log_info("I2C init: clock speed %d kHz\n", I2C_BUS_CLOCK_SPEED / 1000);
         i2c_init(I2C_BUS_CLOCK_SPEED);
-#endif //RS41
+#endif
     }
 
     log_info("SPI init\n");
@@ -121,9 +121,7 @@ int main(void)
 #elif defined(DFM17)
     log_info("Si4063 init\n");
     si4063_init();
-#else
-	Error.  Must defined RS41 or DFM17
-#endif 
+#endif
 
     if (bmp280_enabled) {
         for (int i = 0; i < 3; i++) {