UPD78F0890GK(A)-GAJ-AX NEC, UPD78F0890GK(A)-GAJ-AX Datasheet - Page 272

• Manufacturer Part Number: UPD78F0890GK(A)-GAJ-AX
• Description: 8BIT MCU, 128K FLASH, 7K RAM, LQFP
• Manufacturer: NEC

Specifications of UPD78F0890GK(A)-GAJ-AX

• Controller Family/series: UPD78F
• No. Of I/o's: 55
• Ram Memory Size: 7KB
• Cpu Speed: 20MHz
• No. Of Timers: 10
• No. Of Pwm: RoHS Compliant
• Core Size: 8bit
• Program Memory Size: 128KB
• Oscillator Type: External, Internal

11.1 Functions of Watchdog Timer
signal is generated.
For details of RESF, see CHAPTER 19 RESET FUNCTION.
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The watchdog timer operates on the internal low-speed oscillator clock.
The watchdog timer is used to detect an inadvertent program loop. If a program loop is detected, an internal reset
Program loop is detected in the following cases.
• If the watchdog timer counter overflows
• If a 1-bit manipulation instruction is executed on the watchdog timer enable register (WDTE)
• If data other than “ACH” is written to WDTE
• If data is written to WDTE during a window close period
• If the instruction is fetched from an area not set by the IMS and IXS registers (detection of an invalid check while
• If the CPU accesses an area that is not set by the IMS and IXS registers (excluding FB00H to FFFFH) by
When a reset occurs due to the watchdog timer, bit 4 (WDTRF) of the reset control flag register (RESF) is set to 1.
the CPU hangs up)
executing a read/write instruction (detection of an abnormal access during a CPU program loop)
CHAPTER 11 WATCHDOG TIMER
User’s Manual U17554EJ4V0UD