Added low voltage detection to tempsensor bsp

miosix/arch/cortexM3_stm32/stm32f100cb_tempsensor/interfaces-impl/bsp.cpp

@@ -110,6 +110,12 @@ void showNumber(float number)
     }
 }
 
+void showLowVoltageIndicator()
+{
+    static const char bat[]={0x7c,0x77,0x78,0x0}; //"bAt "
+    memcpy(digits,bat,4);
+}
+
 //
 // AD7789 driver
 //
@@ -162,6 +168,22 @@ unsigned int readAdcValue()
     return result;
 }
 
+//
+// PVD driver
+//
+
+static void configureLowVoltageDetect()
+{
+    PWR->CR |= PWR_CR_PVDE   //Low voltage detect enabled
+             | PWR_CR_PLS_1
+             | PWR_CR_PLS_0; //2.5V threshold
+}
+
+bool lowVoltageCheck()
+{
+    return (PWR->CSR & PWR_CSR_PVDO) ? false : true;
+}
+
 //
 // class NonVolatileStorage
 //
@@ -247,7 +269,7 @@ void IRQbspInit()
     RCC->APB2ENR |= RCC_APB2ENR_IOPAEN | RCC_APB2ENR_IOPBEN |
                     RCC_APB2ENR_IOPCEN | RCC_APB2ENR_IOPDEN |
                     RCC_APB2ENR_AFIOEN | RCC_APB2ENR_SPI1EN;
-    RCC->APB1ENR |= RCC_APB1ENR_TIM3EN;
+    RCC->APB1ENR |= RCC_APB1ENR_TIM3EN | RCC_APB1ENR_PWREN;
     RCC_SYNC();
 
     //Board has no JTAG nor SWD, and those pins are used
@@ -267,6 +289,7 @@ void IRQbspInit()
     GPIOD->CRL=0x22222222; //PD0 and PD1 all out
     
     initAdc();
+    configureLowVoltageDetect();
 
     DefaultConsole::instance().IRQset(intrusive_ref_ptr<Device>(
         new STM32Serial(defaultSerial,defaultSerialSpeed,

miosix/arch/cortexM3_stm32/stm32f100cb_tempsensor/interfaces-impl/bsp_impl.h

@@ -48,6 +48,11 @@ void clearDisplay();
  */
 void showNumber(float number);
 
+/**
+ * Show the word "bAt" on the LED display
+ */
+void showLowVoltageIndicator();
+
 typedef Gpio<GPIOA_BASE,4> cs; ///< For low-level SPI access
 
 /**
@@ -70,6 +75,11 @@ unsigned char readStatusReg();
  */
 unsigned int readAdcValue();
 
+/**
+ * \return true if the supply voltege is high enough
+ */
+bool lowVoltageCheck();
+
 /**
  * This class allows to store non volatile data into the last FLASH page
  * of the microcontroller.