Automatically exit the printer class bootloader and start the application when the...

diff --git a/Bootloaders/Printer/BootloaderPrinter.c b/Bootloaders/Printer/BootloaderPrinter.c
index c459e03..e81646b 100644 (file)
--- a/Bootloaders/Printer/BootloaderPrinter.c
+++ b/Bootloaders/Printer/BootloaderPrinter.c
@@ -73,6 +73,37 @@ struct
  */
 static bool PageDirty = false;
 
+
+/** Flag to indicate if the bootloader should be running, or should exit and allow the application code to run
+ *  via a soft reset. When cleared, the bootloader will abort, the USB interface will shut down and the application
+ *  started via a forced watchdog reset.
+ */
+static bool RunBootloader = true;
+
+/** Magic lock for forced application start. If the HWBE fuse is programmed and BOOTRST is unprogrammed, the bootloader
+ *  will start if the /HWB line of the AVR is held low and the system is reset. However, if the /HWB line is still held
+ *  low when the application attempts to start via a watchdog reset, the bootloader will re-start. If set to the value
+ *  \ref MAGIC_BOOT_KEY the special init function \ref Application_Jump_Check() will force the application to start.
+ */
+uint16_t MagicBootKey ATTR_NO_INIT;
+
+
+/** Special startup routine to check if the bootloader was started via a watchdog reset, and if the magic application
+ *  start key has been loaded into \ref MagicBootKey. If the bootloader started via the watchdog and the key is valid,
+ *  this will force the user application to start via a software jump.
+ */
+void Application_Jump_Check(void)
+{
+       /* If the reset source was the bootloader and the key is correct, clear it and jump to the application */
+       if ((MCUSR & (1 << WDRF)) && (MagicBootKey == MAGIC_BOOT_KEY))
+       {
+               MagicBootKey = 0;
+
+               // cppcheck-suppress constStatement
+               ((void (*)(void))0x0000)();
+       }
+}
+
 /**
  * Determines if a given input byte of data is an ASCII encoded HEX value.
  *
@@ -255,6 +286,10 @@ static void ParseIntelHEXByte(const char ReadCharacter)
                                PageDirty = false;
                        }
 
+                       /* If end of the HEX file reached, the bootloader should exit at next opportunity */
+                       if (HEXParser.RecordType == HEX_RECORD_TYPE_EndOfFile)
+                         RunBootloader = false;
+
                        break;
 
                default:
@@ -273,7 +308,7 @@ int main(void)
        LEDs_SetAllLEDs(LEDMASK_USB_NOTREADY);
        GlobalInterruptEnable();
 
-       for (;;)
+       while (RunBootloader)
        {
                USB_USBTask();
 
@@ -296,6 +331,17 @@ int main(void)
                        LEDs_SetAllLEDs(LEDMASK_USB_READY);
                }
        }
+
+       /* Disconnect from the host - USB interface will be reset later along with the AVR */
+       USB_Detach();
+
+       /* Unlock the forced application start mode of the bootloader if it is restarted */
+       MagicBootKey = MAGIC_BOOT_KEY;
+
+       /* Enable the watchdog and force a timeout to reset the AVR */
+       wdt_enable(WDTO_250MS);
+
+       for (;;);
 }
 
 /** Configures the board hardware and chip peripherals for the demo's functionality. */

diff --git a/Bootloaders/Printer/BootloaderPrinter.h b/Bootloaders/Printer/BootloaderPrinter.h
index 8582d84..4995cdc 100644 (file)
--- a/Bootloaders/Printer/BootloaderPrinter.h
+++ b/Bootloaders/Printer/BootloaderPrinter.h
@@ -63,6 +63,9 @@
                /** LED mask for the library LED driver, to indicate that the USB interface is busy. */
                #define LEDMASK_USB_BUSY           LEDS_LED2
 
+               /** Magic bootloader key to unlock forced application start mode. */
+               #define MAGIC_BOOT_KEY             0xDC42
+
        /* Enums: */
                /** Intel HEX parser state machine states. */
                enum HEX_Parser_States_t