Don't run user application in the bootloader unless a valid app is present (thanks...

[pub/USBasp.git] / Bootloaders / Printer / BootloaderPrinter.c

diff --git a/Bootloaders/Printer/BootloaderPrinter.c b/Bootloaders/Printer/BootloaderPrinter.c
index a19cb06..716a23a 100644 (file)
--- a/Bootloaders/Printer/BootloaderPrinter.c
+++ b/Bootloaders/Printer/BootloaderPrinter.c
@@ -119,9 +119,49 @@ uint16_t MagicBootKey ATTR_NO_INIT;
  */
 void Application_Jump_Check(void)
 {
+       bool JumpToApplication = false;
+
+       #if (BOARD == BOARD_LEONARDO)
+               /* Enable pull-up on the IO13 pin so we can use it to select the mode */
+               PORTC |=  (1 << 7);
+               Delay_MS(10);
+
+               /* If IO13 is not jumpered to ground, start the user application instead */
+               JumpToApplication |= ((PINC & (1 << 7)) != 0);
+
+               /* Disable pull-up after the check has completed */
+               PORTC &= ~(1 << 7);
+       #elif ((BOARD == BOARD_XPLAIN) || (BOARD == BOARD_XPLAIN_REV1))
+               /* Disable JTAG debugging */
+               JTAG_DISABLE();
+
+               /* Enable pull-up on the JTAG TCK pin so we can use it to select the mode */
+               PORTF |= (1 << 4);
+               Delay_MS(10);
+
+               /* If the TCK pin is not jumpered to ground, start the user application instead */
+               JumpToApplication |= ((PINF & (1 << 4)) != 0);
+
+               /* Re-enable JTAG debugging */
+               JTAG_ENABLE();
+       #endif
+
        /* 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))
+         JumpToApplication |= true;
+
+       /* Don't run the user application if the reset vector is blank (no app loaded) */
+       if (pgm_read_word_near(0) == 0xFFFF)
+         JumpToApplication = false;
+
+       /* If a request has been made to jump to the user application, honor it */
+       if (JumpToApplication)
        {
+               /* Turn off the watchdog */
+               MCUSR &= ~(1<<WDRF);
+               wdt_disable();
+
+               /* Clear the boot key and jump to the user application */
                MagicBootKey = 0;
 
                // cppcheck-suppress constStatement