User Manual

2.9 Using EEPROM
The EEPROM is designed to store the data which is not changed very
frequently. This data is given as follows:
 Module ID, configuration settings

COM port configuration settings

Small databases
The erase/write cycle of the EEPROM is limited, the user should not change
the EEPROM frequently for testing. The EEPROM can erase/write in single
byte, so it is very useful in real world applications.
2.10 Using the Watchdog Timer
The watchdog timer of the 7521 series is fixed at 1.6 sec. When the 7521
series is powered up, the watchdog timer will be always enabled. If the
7521 series do not refresh the watchdog timer every 1.6 seconds, the watchdog
will RESET the 7521 series.
The MiniOS7 of the 7521 series will automatically refresh the watchdog after
power up. The user program can call the software driver to tell MiniOS7 to
stop refreshing the watchdog timer, then the user program must refresh the
watchdog timer. If the user program does not refresh the watchdog timer every
1.6 seconds, the watchdog timer will RESET the 7521 series.
7521/2/2A/3/4/7 Series Hardware User’s Manual, Ver. 1.5 Sep/2002, 7Mh-001-15 -----55