C8051F302 Silicon Laboratories Inc, C8051F302 Datasheet - Page 156

• Manufacturer Part Number: C8051F302
• Description: IC 8051 MCU 8K FLASH 11MLP
• Manufacturer: Silicon Laboratories Inc
• Series: C8051F30xr

Specifications of C8051F302

• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 25MHz
• Connectivity: SMBus (2-Wire/I²C), UART/USART
• Peripherals: POR, PWM, Temp Sensor, WDT
• Number Of I /o: 8
• Program Memory Size: 8KB (8K x 8)
• Program Memory Type: FLASH
• Ram Size: 256 x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 3.6 V
• Data Converters: A/D 8x8b
• Oscillator Type: External
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 11-VQFN
• Data Bus Width: 8 bit
• Data Ram Size: 256 B
• Interface Type: I2C, SMBus, UART
• Maximum Clock Frequency: 25 MHz
• Number Of Programmable I/os: 8
• Number Of Timers: 16 bit
• Operating Supply Voltage: 2.7 V to 3.6 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 8 bit
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -
• Lead Free Status / Rohs Status: No

C8051F300/1/2/3/4/5
16.3. Watchdog Timer Mode
A programmable watchdog timer (WDT) function is available through the PCA Module 2. The WDT is used to gen-
erate a reset if the time between writes to the WDT update register (PCA0CPH2) exceed a specified limit. The WDT
can be configured and enabled/disabled as needed by software.
With the WDTE bit set in the PCA0MD register, Module 2 operates as a watchdog timer (WDT). The Module 2 high
byte is compared to the PCA counter high byte; the Module 2 low byte holds the offset to be used when WDT updates
are performed. The Watchdog Timer is enabled on reset. Writes to some PCA registers are restricted while the
Watchdog Timer is enabled.
16.3.1. Watchdog Timer Operation
While the WDT is enabled:
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•
•
•
•
•
While the WDT is enabled, writes to the CR bit will not change the PCA counter state; the counter will run until the
WDT is disabled. The PCA counter run control (CR) will read zero if the WDT is enabled but user software has not
enabled the PCA counter. If a match occurs between PCA0CPH2 and PCA0H while the WDT is enabled, a reset will
be generated. To prevent a WDT reset, the WDT may be updated with a write of any value to PCA0CPH2. Upon a
PCA0CPH2 write, PCA0H plus the offset held in PCA0CPL2 is loaded into PCA0CPH2 (See Figure 16.10).
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PCA counter is forced on.
Writes to PCA0L and PCA0H are not allowed.
PCA clock source bits (CPS2-CPS0) are frozen.
PCA Idle control bit (CIDL) is frozen.
Module 2 is forced into software timer mode.
Writes to the module 2 mode register (PCA0CPM2) are disabled.
PCA0CPL2
C
D
L
I
W
D
T
E
PCA0MD
W
D
C
L
K
Figure 16.10. PCA Module 2 with Watchdog Timer Enabled
PCA0CPH2
C
P
S
2
Write to
C
P
S
1
C
P
S
0
E
C
F
8-bit Adder
Enable
Adder
Enable
Rev. 2.3
PCA0CPH2
Comparator
PCA0H
8-bit
Match
PCA0L Overflow
Reset