diff options
Diffstat (limited to 'cores/arduino/CDC.cpp')
| -rw-r--r-- | cores/arduino/CDC.cpp | 43 |
1 files changed, 29 insertions, 14 deletions
diff --git a/cores/arduino/CDC.cpp b/cores/arduino/CDC.cpp index f19b44c..0a743e1 100644 --- a/cores/arduino/CDC.cpp +++ b/cores/arduino/CDC.cpp @@ -34,6 +34,8 @@ typedef struct static volatile LineInfo _usbLineInfo = { 57600, 0x00, 0x00, 0x00, 0x00 }; static volatile int32_t breakValue = -1; +bool _updatedLUFAbootloader = false; + #define WEAK __attribute__ ((weak)) extern const CDCDescriptor _cdcInterface PROGMEM; @@ -99,24 +101,32 @@ bool CDC_Setup(USBSetup& setup) // with a relatively long period so it can finish housekeeping tasks // like servicing endpoints before the sketch ends -#ifndef MAGIC_KEY -#define MAGIC_KEY 0x7777 -#endif -#ifndef MAGIC_KEY_POS -#define MAGIC_KEY_POS 0x0800 + uint16_t magic_key_pos = MAGIC_KEY_POS; + +// If we don't use the new RAMEND directly, check manually if we have a newer bootloader. +// This is used to keep compatible with the old leonardo bootloaders. +// You are still able to set the magic key position manually to RAMEND-1 to save a few bytes for this check. +#if MAGIC_KEY_POS != (RAMEND-1) + // For future boards save the key in the inproblematic RAMEND + // Which is reserved for the main() return value (which will never return) + if (_updatedLUFAbootloader) { + // horray, we got a new bootloader! + magic_key_pos = (RAMEND-1); + } #endif // We check DTR state to determine if host port is open (bit 0 of lineState). if (1200 == _usbLineInfo.dwDTERate && (_usbLineInfo.lineState & 0x01) == 0) { #if MAGIC_KEY_POS != (RAMEND-1) - *(uint16_t *)(RAMEND-1) = *(uint16_t *)MAGIC_KEY_POS; - *(uint16_t *)MAGIC_KEY_POS = MAGIC_KEY; -#else - // for future boards save the key in the inproblematic RAMEND - // which is reserved for the main() return value (which will never return) - *(uint16_t *)MAGIC_KEY_POS = MAGIC_KEY; + // Backup ram value if its not a newer bootloader. + // This should avoid memory corruption at least a bit, not fully + if (magic_key_pos != (RAMEND-1)) { + *(uint16_t *)(RAMEND-1) = *(uint16_t *)magic_key_pos; + } #endif + // Store boot key + *(uint16_t *)magic_key_pos = MAGIC_KEY; wdt_enable(WDTO_120MS); } else @@ -129,10 +139,15 @@ bool CDC_Setup(USBSetup& setup) wdt_disable(); wdt_reset(); #if MAGIC_KEY_POS != (RAMEND-1) - *(uint16_t *)MAGIC_KEY_POS = *(uint16_t *)(RAMEND-1); -#else - *(uint16_t *)MAGIC_KEY_POS = 0x0000; + // Restore backed up (old bootloader) magic key data + if (magic_key_pos != (RAMEND-1)) { + *(uint16_t *)magic_key_pos = *(uint16_t *)(RAMEND-1); + } else #endif + { + // Clean up RAMEND key + *(uint16_t *)magic_key_pos = 0x0000; + } } } return true; |