Diff: SysMngmt.cpp

Revision:

1:e02eb179aed3

Parent:

0:e516fcccccda

Child:

2:baeb80c778f7

--- a/SysMngmt.cpp	Wed Oct 01 12:52:26 2014 +0000
+++ b/SysMngmt.cpp	Sat Oct 04 16:19:45 2014 +0000
@@ -43,13 +43,28 @@
 }
 */
 
+/*
+    http://developer.mbed.org/users/AjK/notebook/getting-closer-to-the-hardware/
+    
+    extern "C" means this is linked assuming it's C code
+    C++ linker appearently adds extra crap with the function arguments keeping functions of this kind from linking properly
+    
+    Interrupt handler, This is probably linked to the Timer 2 interrupt request somewhere by the libraries
+*/
 extern "C" void TIMER2_IRQHandler(void)
 {
     if((LPC_TIM2->IR & 0x01) == 0x01) // if MR0 interrupt
     {
-        //printf("Every 1ms\n\r");
+        // This probably shouldn't be here, never have a printf() in an interrupt, locks up the main thread
+        // printf("Every 1ms\n\r");
+        
         LPC_TIM2->IR |= 1 << 0; // Clear MR0 interrupt flag
         
+        // gonna hope all these calculations are correct
+        // writes to RTC store, but there's no read code here
+        // 2 misleading things. First, RTC store writes to a general purpose register
+        // secondly, no code reads from this register in this .cpp, but maybe some other code does
+        
         Bat_I_Ratio=BatISense.read();
         BATA_msec=(((Bat_I_Ratio*3.3) - BAT_ISENSE_OFFSET_V)/BAT_ISENSE_INCREMENT);
         BATmA_Hr+=(BATA_msec*MSEC_HRS);
@@ -60,11 +75,14 @@
         store.write(DCA_msec,1);
         
         LPC_TIM2->TCR       |=  (1<<1);                     //Reset Timer1
-        LPC_TIM2->TCR       &=  ~(1<<1);                     //Re Enable Timer1   
+        LPC_TIM2->TCR       &=  ~(1<<1);                    //Re Enable Timer1   
     }
 }    
 
-
+/*
+    Appears to read a whole bunch of DigitalOut pins in void PollSwitch(), store the value in uint16_t Rxpoll,
+    and write the result to the CAN bus
+*/
 void Poll()
 {
     uint16_t Rxpoll;
@@ -214,7 +232,8 @@
         
         ->MR0                       0x4009 0018 (Match Register)
         
-        ->MCR                       0x4009 0014 (Match Control Register)
+        ->MCR                       0x4009 0014 (Match Control Register) What to do when Match Register matches the Timer Counter
+        |= (1<<0);                  0 Bit (Interrupt on MR0, interrupt generated when MR0 matches the value in TC)
         
     */
     LPC_SC->PCONP       |= (1<<22);                     //PoewerOn Timer/Counter2
@@ -223,6 +242,21 @@
     LPC_TIM2->MR0       =   11999;                      // 1msec
     LPC_TIM2->MCR       |=  (1<<0);
     
+    /*
+        Nested Vectored Interrupt Controller (NVIC)
+        
+        NVIC_SetPriority(IRQn_Type IRQn, uint32_t priority)
+            sets priority of an interrupt
+        
+        IRQn_Type
+            Interrupt number definitions
+            Interrupt Request (IRQ)
+        
+        NVIC_EnableIRQ(IRQn_Type IRQn)
+            Enable external interrupt (in this case, the TIMER2_IRQHandler(void) function above gets called every time
+            Timer2 generates an interrupt signal)
+            
+    */
     NVIC_SetPriority(TIMER0_IRQn,200);                  //IMD Capture Interrupt
     NVIC_SetPriority(TIMER1_IRQn,200);                  //IMD 1msec sampling Interrupt
     NVIC_SetPriority(TIMER2_IRQn,1);                    //Battery 1msec sampling Interrupt