P83C654X2FBD/CV710 NXP Semiconductors, P83C654X2FBD/CV710 Datasheet - Page 64

• Manufacturer Part Number: P83C654X2FBD/CV710
• Description: 8-bit Microcontrollers - MCU P83C654X2FBD/LQFP44/TRAYBM//CV
• Manufacturer: NXP Semiconductors

Specifications of P83C654X2FBD/CV710

• Core: 80C51
• Data Bus Width: 8 bit
• Maximum Clock Frequency: 16 MHz
• Program Memory Size: 16 KB
• Data Ram Size: 256 B
• Operating Supply Voltage: 5 V
• Package / Case: SOT-187-2
• Mounting Style: SMD/SMT
• Interface Type: I2C, Serial
• Number Of Programmable I/os: 4
• Number Of Timers: 3
• Processor Series: 80C51
• Program Memory Type: OTP EPROM

Philips Semiconductors
HARDWARE WATCHDOG TIMER (ONE-TIME
ENABLED WITH RESET-OUT FOR P8XC654X2)
The WDT is intended as a recovery method in situations where the
CPU may be subjected to software upset. The WDT consists of a
14-bit counter and the WatchDog Timer reset (WDTRST) SFR. The
WDT is disabled at reset.
2004 Apr 20
80C51 8-bit microcontroller family
256B RAM, low voltage (2.7 to 5.5 V), low power, high speed
(30/33 MHz)
16 kB OTP/ROM,
64
Using the WDT
To enable the WDT, the user must write 01EH and 0E1H in sequence
to the WDTRST, SFR location 0A6H. When the WDT is enabled, the
user needs to service it by writing 01EH and 0E1H to WDTRST to
avoid a WDT overflow. The 14-bit counter overflows when it reaches
16383 (3FFFH) and this will reset the device. When the WDT is
enabled, it will increment every machine cycle while the oscillator is
running. This means the user must reset the WDT at least every
16383 machine cycles. To reset the WDT, the user must write 01EH
and 0E1H to WDTRST. WDTRST is a write only register. The WDT
counter cannot be read or written. When the WDT overflows, it will
generate an output RESET pulse at the reset pin (see note below).
The RESET pulse duration is 98 T
12-clock mode), where T
WDT, it should be serviced in those sections of code that will
periodically be executed within the time required to prevent a WDT
reset.
P83C654X2/P87C654X2
osc
= 1/f
osc
. To make the best use of the
osc
(6-clock mode; 196 in
Product data