HAL example added

STM32/libraries/BoardExamples/examples/Discovery407VG/HAL/HAL_timer1_serialOut/HAL_timer1_serialOut.ino

@@ -0,0 +1,48 @@
+/*
+ HAL ( Hardware Abstraction Layer )
+
+ Example on how access the HAL within the STM32GENERIC Arduino framework
+
+ example copied from
+ April 2017 michael_l
+
+ http://www.stm32duino.com/viewtopic.php?f=42&t=1966&start=90#p27155
+
+*/
+#include "STM32_HAL.h"
+uint32_t prev = 0;
+int seconds = 0;
+
+static TIM_HandleTypeDef s_TimerInstance = 
+{
+  .Instance = TIM2
+};
+
+void setup() 
+{
+  Serial.begin(115200); // Serial is SerialUSB
+
+  __TIM2_CLK_ENABLE();
+  s_TimerInstance.Init.Prescaler = 42000 - 1; //APB1 TIM2 has 84MHZ,
+  s_TimerInstance.Init.CounterMode = TIM_COUNTERMODE_UP;
+  s_TimerInstance.Init.Period = 2000 - 1; // prescaler gives 2khz time base
+  s_TimerInstance.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
+  s_TimerInstance.Init.RepetitionCounter = 0;
+  HAL_TIM_Base_Init(&s_TimerInstance);
+  HAL_TIM_Base_Start(&s_TimerInstance);
+}
+
+void loop() 
+{
+  if (__HAL_TIM_GET_COUNTER(&s_TimerInstance) == 0) 
+  {
+    uint32_t now = micros();
+    Serial.print("diff=");
+    Serial.println(now - prev);
+    Serial.println(now);
+    prev = micros();
+
+    Serial.print(seconds++);
+    Serial.println(" seconds");
+  }
+}