Internal oscillator trim value handling for preprogrammed FREESCALE (former Motorola) microcontroller on SPRINT MC68HC908Qx ----------- All 908Qx devices are factory programmed with a trim value in a reserved FLASH location, $FFC0. This value can be copied from the FLASH to the OSCTRIM register during RESET initialisation. Reset loads OSCTRIM with a default value of $80. If you turn ERASING ON the factory programmed OSCTRIM value will be saved, provided that the correct security key was entered at [6h-Dh]. The OSCTRIM value can also be read out, just type 7Fh at address 0h in the editor. This hidden setting can also be used to reprogram the TRIM value with the setting at the OSCTRIM address (CAUTION: this setting will MASS erase the flash memory, erasing also the OSCTRIM address). Please consider regarding the security key: for READ/PROGRAM/VERIFY operation the security key must stay at [FFF6h-FFFDh]. for ERASE operation the (former) security key must stay at [6h-Dh] and the new key at [FFF6h-FFFDh]. MM908E62x ----------------------- MM908E623/624/625 devices are factory programmed with a trim value in a standard FLASH location, $FDC2. This value can be copied from the FLASH to the OSCTRIM register during RESET initialisation. Reset loads OSCTRIM with a default value of $80. If you turn ERASING ON the factory programmed OSCTRIM value will be saved, provided that the correct security key was entered at [6h-Dh]. The datafile must contain 0xFF at address $FDC2. The OSCTRIM value can also be read out, just type 7Fh at address 0h in the editor. This hidden setting can also be used to reprogram the TRIM value with the setting at the OSCTRIM address (CAUTION: this setting will MASS erase the flash memory, erasing also the OSCTRIM address). Please consider regarding the security key: for READ/PROGRAM/VERIFY operation the security key must stay at [FFF6h-FFFDh]. for ERASE operation the (former) security key must stay at [6h-Dh] and the new key at [FFF6h-FFFDh]. Status: 08/05/2005 (C5/2005)