Console: Limit the problem when printing from interrupt

This commits adds a consolePutcharFromISR frunction that only prints in
the local buffer. This limits the amount of data that can be printed from an 
interrupt but it also prevents the firmware to crash as described in #89

modules/interface/console.h

@@ -1,6 +1,6 @@
 /**
- *    ||          ____  _ __                           
- * +------+      / __ )(_) /_______________ _____  ___ 
+ *    ||          ____  _ __
+ * +------+      / __ )(_) /_______________ _____  ___
  * | 0xBC |     / __  / / __/ ___/ ___/ __ `/_  / / _ \
  * +------+    / /_/ / / /_/ /__/ /  / /_/ / / /_/  __/
  *  ||  ||    /_____/_/\__/\___/_/   \__,_/ /___/\___/
@@ -45,11 +45,23 @@ bool consoleTest(void);
  */
 int consolePutchar(int ch);
 
+/**
+ * Put a character to the console buffer
+ *
+ * @param ch character that shall be printed
+ * @return The character casted to unsigned int or EOF in case of error
+ *
+ * @note This version can be called by interrup. In such case the internal
+ * buffer is going to be used. If a task currently is printing or if the
+ * interrupts prints too much the data will be ignored.
+ */
+int consolePutcharFromISR(int ch);
+
 /**
  * Put a null-terminated string on the console buffer
  *
  * @param str Null terminated string
- * @return a nonnegative number on success, or EOF on error. 
+ * @return a nonnegative number on success, or EOF on error.
  */
 int consolePuts(char *str);
 
@@ -60,7 +72,7 @@ void consoleFlush(void);
 
 /**
  * Macro implementing consolePrintf with eprintf
- * 
+ *
  * @param FMT String format
  * @patam ... Parameters to print
  */

modules/src/console.c

@@ -1,6 +1,6 @@
 /**
- *    ||          ____  _ __                           
- * +------+      / __ )(_) /_______________ _____  ___ 
+ *    ||          ____  _ __
+ * +------+      / __ )(_) /_______________ _____  ___
  * | 0xBC |     / __  / / __/ ___/ ___/ __ `/_  / / _ \
  * +------+    / /_/ / / /_/ /__/ /  / /_/ / / /_/  __/
  *  ||  ||    /_____/_/\__/\___/_/   \__,_/ /___/\___/
@@ -32,6 +32,8 @@
 
 #include "crtp.h"
 
+#include "stm32fxxx.h"
+
 CRTPPacket messageToPrint;
 xSemaphoreHandle synch = NULL;
 
@@ -65,7 +67,7 @@ void consoleInit()
   messageToPrint.size = 0;
   messageToPrint.header = CRTP_HEADER(CRTP_PORT_CONSOLE, 0);
   vSemaphoreCreateBinary(synch);
-  
+
   isInit = true;
 }
 
@@ -77,9 +79,15 @@ bool consoleTest(void)
 int consolePutchar(int ch)
 {
   int i;
+  bool isInInterrupt = (SCB->ICSR & SCB_ICSR_VECTACTIVE_Msk) != 0;
 
-  if (!isInit)
+  if (!isInit) {
     return 0;
+  }
+
+  if (isInInterrupt) {
+    return consolePutcharFromISR(ch);
+  }
 
   if (xSemaphoreTake(synch, portMAX_DELAY) == pdTRUE)
   {
@@ -102,17 +110,32 @@ int consolePutchar(int ch)
     }
     xSemaphoreGive(synch);
   }
-  
+
   return (unsigned char)ch;
 }
 
+int consolePutcharFromISR(int ch) {
+  BaseType_t higherPriorityTaskWoken;
+
+  if (xSemaphoreTakeFromISR(synch, &higherPriorityTaskWoken) == pdTRUE) {
+    if (messageToPrint.size < CRTP_MAX_DATA_SIZE)
+    {
+      messageToPrint.data[messageToPrint.size] = (unsigned char)ch;
+      messageToPrint.size++;
+    }
+    xSemaphoreGiveFromISR(synch, &higherPriorityTaskWoken);
+  }
+
+  return ch;
+}
+
 int consolePuts(char *str)
 {
   int ret = 0;
-  
+
   while(*str)
     ret |= consolePutchar(*str++);
-  
+
   return ret;
 }