PIC16F688-I/P Microchip Technology, PIC16F688-I/P Datasheet - Page 115

• Manufacturer Part Number: PIC16F688-I/P
• Description: IC PIC MCU FLASH 4KX14 14DIP
• Manufacturer: Microchip Technology
• Series: PIC® 16Fr

Specifications of PIC16F688-I/P

• Program Memory Type: FLASH
• Program Memory Size: 7KB (4K x 14)
• Package / Case: 14-DIP (0.300", 7.62mm)
• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: UART/USART
• Peripherals: Brown-out Detect/Reset, POR, WDT
• Number Of I /o: 12
• 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: SCI/USART
• Maximum Clock Frequency: 20 MHz
• Number Of Programmable I/os: 12
• Number Of Timers: 2
• Operating Supply Voltage: 2 V to 5.5 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: Through Hole
• 3rd Party Development Tools: 52715-96, 52716-328, 52717-734
• Development Tools By Supplier: PG164130, DV164035, DV244005, DV164005, PG164120, ICE2000, DM163014, DM164120-4
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 8-ch x 10-bit
• Data Rom Size: 256 B
• Height: 3.3 mm
• Length: 19.05 mm
• Supply Voltage (max): 5.5 V
• Supply Voltage (min): 2 V
• Width: 6.35 mm
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: AC162066 - HEADER INTRFC MPLAB ICD2 20PINAC162061 - HEADER INTRFC MPLAB ICD2 20PINDM163029 - BOARD PICDEM FOR MECHATRONICSAC162056 - HEADER INTERFACE ICD2 16F688ACICE0207 - MPLABICE 14P 300 MIL ADAPTERAC124001 - MODULE SKT PROMATEII 8DIP/SOIC
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

11.7
For PIC16F688, the WDT has been modified from
previous 16F devices. The new WDT is code and
functionally compatible with previous 16F WDT
modules and adds a 16-bit prescaler to the WDT. This
allows the user to have a scaler value for the WDT and
TMR0 at the same time. In addition, the WDT time-out
value can be extended to 268 seconds. WDT is cleared
under certain conditions described in Table 11-7.
11.7.1
The WDT derives its time base from the 31 kHz
LFINTOSC. The LTS bit 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 16 ms, which is
compatible with the time base generated with previous
16F microcontroller versions.
FIGURE 11-9:
TABLE 11-7:
 2004 Microchip Technology Inc.
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:
31 kHz
Watchdog Timer (WDT)
Note 1: This is the shared Timer0/WDT prescaler. See Section 5.4 “Prescaler” for more information.
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 Configuration Word Register
SWDTEN from WDTCON
Conditions
16-bit WDT Prescaler
WDTPS<3:0>
From TMR0 Clock Source
Preliminary
A new prescaler has been added to the path between
the INTRC and the multiplexers used to select the path
for the WDT. This prescaler is 16 bits and can be
programmed to divide the INTRC by 32 to 65536,
giving the WDT a nominal range of 1 ms to 268s.
11.7.2
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 (WDTCON<0>) 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 (OPTION_REG) have the
same function as in previous versions of the 16F family
of microcontrollers. See Section 5.0 “Timer0 Module”
for more information.
0
1
WDT CONTROL
PSA
Cleared until the end of OST
WDT Time-out
0
PIC16F688
Prescaler
Cleared
1
8
WDT
DS41203B-page 113
(1)
PSA
PS<2:0>
To TMR0