AT89C51CC03U-RDRIM Atmel, AT89C51CC03U-RDRIM Datasheet - Page 81

• Manufacturer Part Number: AT89C51CC03U-RDRIM
• Description: IC 8051 MCU FLASH 64K 64VQFP
• Manufacturer: Atmel
• Series: AT89C CANr

Specifications of AT89C51CC03U-RDRIM

• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 40MHz
• Connectivity: CAN, SPI, UART/USART
• Peripherals: POR, PWM, WDT
• Number Of I /o: 36
• Program Memory Size: 64KB (64K x 8)
• Program Memory Type: FLASH
• Eeprom Size: 2K x 8
• Ram Size: 2.25K x 8
• Voltage - Supply (vcc/vdd): 3 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: External
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 64-TQFP, 64-VQFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: AT89C51CC03URDRTR

Watchdog Timer
Figure 42. Watchdog Timer
4182O–CAN–09/08
Fwd Clock
RESET
-
AT89C51CC03 contains a powerful programmable hardware Watchdog Timer (WDT)
that automatically resets the chip if it software fails to reset the WDT before the selected
time interval has elapsed. It permits large Time-Out ranking from 16ms to 2s @Fosc =
12MHz in X1 mode.
This WDT consists of a 14-bit counter plus a 7-bit programmable counter, a Watchdog
Timer reset register (WDTRST) and a Watchdog Timer programming (WDTPRG) regis-
ter. When exiting reset, the WDT is -by default- disable.
To enable the WDT, the user has to write the sequence 1EH and E1H into WDTRST
register no instruction in between. When the Watchdog Timer is enabled, it will incre-
ment every machine cycle while the oscillator is running and there is no way to disable
the WDT except through reset (either hardware reset or WDT overflow reset). When
WDT overflows, it will generate an output RESET pulse at the RST pin. The RESET
pulse duration is 96xT
should be serviced in those sections of code that will periodically be executed within the
time required to prevent a WDT reset
Note:
-
WDTPRG
-
When the Watchdog is enable it is impossible to change its period.
WDTRST
-
14-bit COUNTER
Enable
-
2
OSC
1
, where T
0
WR
OSC
=1/F
Control
Decoder
OSC
7-bit COUNTER
. To make the best use of the WDT, it
Outputs
AT89C51CC03
RESET
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