PIC16F914-I/PT Microchip Technology, PIC16F914-I/PT Datasheet - Page 5

• Manufacturer Part Number: PIC16F914-I/PT
• Description: IC PIC MCU FLASH 4KX14 44TQFP
• Manufacturer: Microchip Technology
• Series: PIC® 16Fr

Specifications of PIC16F914-I/PT

• Program Memory Type: FLASH
• Program Memory Size: 7KB (4K x 14)
• Package / Case: 44-TQFP, 44-VQFP
• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, LCD, POR, PWM, WDT
• Number Of I /o: 35
• Eeprom Size: 256 x 8
• Ram Size: 256 x 8
• Voltage - Supply (vcc/vdd): 2 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Processor Series: PIC16F
• Core: PIC
• Data Bus Width: 8 bit
• Data Ram Size: 256 B
• Interface Type: SSP/I2C/AUSART/SPI
• Maximum Clock Frequency: 20 MHz
• Number Of Programmable I/os: 35
• Number Of Timers: 3
• Operating Supply Voltage: 2 V to 5.5 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: 52715-96, 52716-328, 52717-734
• Development Tools By Supplier: PG164130, DV164035, DV244005, DV164005, PG164120, ICE2000, DV164120, DM163029
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 8-ch x 10-bit
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: XLT44PT3 - SOCKET TRAN ICE 44MQFP/TQFPAC164305 - MODULE SKT FOR PM3 44TQFP444-1001 - DEMO BOARD FOR PICMICRO MCUAC164020 - MODULE SKT PROMATEII 44TQFP
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

4. Module: Timer0 and WDT Prescaler
© 2009 Microchip Technology Inc.
A spurious Reset may occur if the Timer0/Watch-
dog Timer (WDT) prescaler is assigned from the
WDT to Timer0 and then back to the WDT.
Summary
The issue only arises when all of the below
conditions are met:
• Timer0 external clock input (TOCKI) is enabled.
• The Prescaler is assigned to the WDT, then to
• During the assignments, the T0CKI pin is high
• The 1:1 Prescaler option is chosen.
Description
On a POR, the Timer0/WDT prescaler is assigned
to the WDT.
If the prescaler is reassigned to Timer0 and Timer0
external clock input (TOCKI) is enabled then the
prescaler would be clocked by a transition on the
TOCKI pin.
On power-up, the TOCKI pin is (by default)
enabled for Timer0 in the OPTION register.
If the T0CKI pin is:
• High and Timer0 is configured to transition on a
• Low and Timer0 is configured to transition on a
Then, if the prescaler is reassigned to the WDT, a
clock pulse to the prescaler will be generated on
the reassignment.
If the prescaler is configured for the 1:1 option, the
clock pulse will incorrectly cause a WDT Time-out
Reset of the device.
Work around
2.
3.
1.
the Timer0 and back to the WDT.
when bit TOSE is set, or low when TOSE is
clear.
falling edge (TOSE set), or
rising edge (TOSE clear)
Disable the Timer0 external clock input by
clearing the TOCKI bit in the OPTION
register.
Modify the TOSE bit in the OPTION register to
the opposite configuration for the logic level
on the T0CKI pin.
Select a prescaler rate other than 1:1 and
issue a CLRWDT instruction before switching
to the final prescaler rate.
Assignment Spurious Reset
Affected Silicon Revisions
PIC16F913/914
PIC16F916/917
PIC16F946
A0
A0
A0
X
X
X
A1
A1
A1
X
X
X
PIC16F91X/946
A2
A2
A2
X
X
X
A3
B0
X
X
B1
X
B2
DS80238C-page 5
X
B3
X