Merge pull request #67 from DRracer/watchdog

Add watchdog implementation + use it in main()

src/hal/CMakeLists.txt

@@ -8,4 +8,5 @@ target_sources(
           tmc2130.cpp
           adc.cpp
           avr/spi.cpp
+          avr/watchdog.cpp
   )

src/hal/avr/cpu.cpp

@@ -1,4 +1,6 @@
 #include "../cpu.h"
+#include <avr/interrupt.h>
+#include "../watchdog.h"
 
 namespace hal {
 namespace cpu {
@@ -6,5 +8,12 @@ namespace cpu {
 void Init() {
 }
 
+void Reset() {
+    cli();
+    watchdog::Enable(watchdog::configuration::compute(0)); //quickest watchdog reset
+    for (;;)
+        ; //endless loop while waiting for the watchdog to reset
+}
+
 } // namespace CPU
 } // namespace hal

src/hal/avr/watchdog.cpp

@@ -0,0 +1,20 @@
+#include "../watchdog.h"
+#include <avr/wdt.h>
+
+namespace hal {
+namespace watchdog {
+
+void Enable(const configuration &config) {
+    wdt_enable(config.prescalerBits);
+}
+
+void Disable() {
+    wdt_disable();
+}
+
+void Reset() {
+    wdt_reset();
+}
+
+} // namespace watchdog
+} // namespace hal

src/hal/cpu.h

@@ -12,6 +12,7 @@ namespace cpu {
 
 /// CPU init routines (not really necessary for the AVR)
 void Init();
+void Reset();
 
 } // namespace cpu
 } // namespace hal

src/hal/watchdog.h

@@ -1,13 +1,55 @@
 #pragma once
+#include <stdint.h>
 
 namespace hal {
 
 /// Hardware Abstraction Layer for the CPU's internal watchdog
 namespace watchdog {
 
+#if defined(__AVR__)
+constexpr uint32_t F_WDT = 128000; //frequency of the watchdog unit in Hz
+constexpr uint32_t basePrescaler = 2048; //what prescalerBits==0 actually does.
+constexpr uint8_t maxPrescaler = 9; //the maximum value prescalerBits can take
+constexpr uint8_t reloadBits = 0; //number of bits in the reload register
+#elif defined(__STM32__) //@todo to be changed to the final form
+constexpr uint32_t F_WDT = 32000; //frequency of the watchdog unit in Hz
+constexpr uint32_t basePrescaler = 4; //what prescalerBits==0 actually does.
+constexpr uint8_t maxPrescaler = 6; //the maximum value prescalerBits can take
+constexpr uint8_t reloadBits = 12; //number of bits in the reload register
+#endif
+
+struct configuration {
+    uint8_t prescalerBits;
+    uint16_t reload;
+
+public:
+    static constexpr configuration compute(uint16_t timeout) {
+        // uint8_t prescalerBits = 0;
+        // uint32_t ticks = timeout * F_WDT / (basePrescaler * (1 << prescalerBits));
+        // while ((ticks >= (1 << reloadBits)) && (prescalerBits < maxPrescaler)) {
+        //     prescalerBits++;
+        //     ticks >>= 1;
+        // }
+        // if ((prescalerBits == 0) && (ticks == 0))
+        //     ticks = 1; //1 tick is minimum
+        // configuration config = { prescalerBits, static_cast<uint16_t>(ticks - 1) };
+        // return config;
+        uint8_t prescalerBits = 0;
+        uint32_t ticks = 1;
+        switch (timeout) {
+        case 8000:
+            prescalerBits = 9;
+        }
+
+        configuration config = { prescalerBits, static_cast<uint16_t>(ticks - 1) };
+        return config;
+    }
+};
+
 /// watchdog interface
-void ConfigureWatchDog(uint16_t period);
+void Enable(const configuration &config);
-void ResetWatchDog();
+void Disable();
+void Reset();
 
 } // namespace watchdog
 } // namespace hal

src/main.cpp

@@ -4,6 +4,7 @@
 #include "hal/shr16.h"
 #include "hal/spi.h"
 #include "hal/usart.h"
+#include "hal/watchdog.h"
 
 #include "pins.h"
 #include <avr/interrupt.h>
@@ -96,6 +97,8 @@ void setup() {
 
     mt::timebase.Init();
 
+    watchdog::Enable(watchdog::configuration::compute(8000)); //set 8s timeout
+
     mg::globals.Init();
 
     // watchdog init
@@ -291,12 +294,13 @@ void ProcessRequestMsg(const mp::RequestMsg &rq) {
         break;
     case mp::RequestMsgCodes::Reset:
         // immediately reset the board - there is no response in this case
-        break; // @@TODO
+        hal::cpu::Reset();
+        break;
     case mp::RequestMsgCodes::Version:
         ReportVersion(rq);
         break;
     case mp::RequestMsgCodes::Wait:
-        break; // @@TODO
+        break; // @@TODO - not used anywhere yet
     case mp::RequestMsgCodes::Cut:
     case mp::RequestMsgCodes::Eject:
     case mp::RequestMsgCodes::Load:
@@ -363,7 +367,8 @@ void loop() {
     ms::selector.Step();
     mui::userInput.Step();
     currentCommand->Step();
-    // add a watchdog reset
+
+    hal::watchdog::Reset();
 }
 
 int main() {