PIC16F684T-E/ST Microchip Technology, PIC16F684T-E/ST Datasheet - Page 112

• Manufacturer Part Number: PIC16F684T-E/ST
• Description: IC PIC MCU FLASH 2KX14 14TSSOP
• Manufacturer: Microchip Technology
• Series: PIC® 16Fr

Specifications of PIC16F684T-E/ST

• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 20MHz
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 12
• Program Memory Size: 3.5KB (2K x 14)
• Program Memory Type: FLASH
• Eeprom Size: 256 x 8
• Ram Size: 128 x 8
• Voltage - Supply (vcc/vdd): 2 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 125°C
• Package / Case: 14-TSSOP
• For Use With: XLT14SS-1 - SOCKET TRANSITION 14DIP/14SSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Connectivity: -

PIC16F684
12.6
The WDT has the following features:
• Operates from the LFINTOSC (31 kHz)
• Contains a 16-bit prescaler
• Shares an 8-bit prescaler with Timer0
• Time-out period is from 1 ms to 268 seconds
• Configuration bit and software controlled
WDT is cleared under certain conditions described in
Table 12-7.
12.6.1
The WDT derives its time base from the 31 kHz
LFINTOSC. The LTS bit of the OSCCON register does
not reflect that the LFINTOSC is enabled.
The value of WDTCON is ‘---0 1000’ on all Resets.
This gives a nominal time base of 17 ms.
FIGURE 12-9:
TABLE 12-7:
DS41202F-page 110
WDTE = 0
CLRWDT Command
Oscillator Fail Detected
Exit Sleep + System Clock = T1OSC, EXTRC, INTRC, EXTCLK
Exit Sleep + System Clock = XT, HS, LP
LFINTOSC Clock
Note:
Note 1: This is the shared Timer0/WDT prescaler. See Section 5.0 “Timer0 Module” for more information.
31 kHz
Watchdog Timer (WDT)
WDT OSCILLATOR
When the Oscillator Start-up Timer (OST)
is invoked, the WDT is held in Reset,
because the WDT Ripple Counter is used
by the OST to perform the oscillator delay
count. When the OST count has expired,
the WDT will begin counting (if enabled).
WDT STATUS
WATCHDOG TIMER BLOCK DIAGRAM
WDTE from the Configuration Word Register
SWDTEN from WDTCON
Conditions
16-bit WDT Prescaler
WDTPS<3:0>
From Timer0 Clock Source
12.6.2
The WDTE bit is located in the Configuration Word
register. When set, the WDT runs continuously.
When the WDTE bit in the Configuration Word register
is set, the SWDTEN bit of the WDTCON register has no
effect. If WDTE is clear, then the SWDTEN bit can be
used to enable and disable the WDT. Setting the bit will
enable it and clearing the bit will disable it.
The PSA and PS<2:0> bits of the OPTION register
have the same function as in previous versions of the
PIC16F684
Section 5.0 “Timer0 Module” for more information.
0
1
WDT CONTROL
PSA
Family
Cleared until the end of OST
WDT Time-out
© 2007 Microchip Technology Inc.
0
of
Prescaler
microcontrollers.
Cleared
1
8
WDT
(1)
PSA
PS<2:0>
To Timer0
See