PIC16F870-I/SS Microchip Technology, PIC16F870-I/SS Datasheet - Page 101

• Manufacturer Part Number: PIC16F870-I/SS
• Description: IC MCU FLASH 2KX14 EE 28SSOP
• Manufacturer: Microchip Technology
• Series: PIC® 16Fr

Specifications of PIC16F870-I/SS

• Core Size: 8-Bit
• Program Memory Size: 3.5KB (2K x 14)
• Core Processor: PIC
• Speed: 20MHz
• Connectivity: UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 22
• Program Memory Type: FLASH
• Eeprom Size: 64 x 8
• Ram Size: 128 x 8
• Voltage - Supply (vcc/vdd): 4 V ~ 5.5 V
• Data Converters: A/D 5x10b
• Oscillator Type: External
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 28-SSOP
• Controller Family/series: PIC16F
• No. Of I/o's: 22
• Eeprom Memory Size: 64Byte
• Ram Memory Size: 128Byte
• Cpu Speed: 20MHz
• No. Of Timers: 3
• Processor Series: PIC16F
• Core: PIC
• Data Bus Width: 8 bit
• Data Ram Size: 128 B
• Interface Type: USART
• Maximum Clock Frequency: 20 MHz
• Number Of Programmable I/os: 22
• Number Of Timers: 8
• 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, DM163022, DV164120
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 28 bit
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: I3-DB16F871 - BOARD DAUGHTER ICEPIC3AC164307 - MODULE SKT FOR PM3 28SSOPAC164020 - MODULE SKT PROMATEII 44TQFPXLT28SS-1 - SOCKET TRANSITION ICE 28SSOP
• Lead Free Status / Rohs Status: Details

11.12 Watchdog Timer (WDT)
The Watchdog Timer is a free running on-chip RC oscil-
lator which does not require any external components.
This RC oscillator is separate from the RC oscillator of
the OSC1/CLKI pin. That means that the WDT will run,
even if the clock on the OSC1/CLKI and OSC2/CLKO
pins of the device has been stopped, for example, by
execution of a SLEEP instruction.
During normal operation, a WDT time-out generates a
device RESET (Watchdog Timer Reset). If the device is
in SLEEP mode, a WDT time-out causes the device to
wake-up
(Watchdog Timer Wake-up). The TO bit in the STATUS
register will be cleared upon a Watchdog Timer
time-out.
The WDT can be permanently disabled by clearing
configuration bit WDTEN (Section 11.1).
FIGURE 11-10:
TABLE 11-7:
 2003 Microchip Technology Inc.
2007h
81h,181h
Legend:
Note 1:
Address
Note:
and
Shaded cells are not used by the Watchdog Timer.
See Register 11-1 for operation of these bits.
PSA and PS2:PS0 are bits in the OPTION_REG register.
Config. bits
OPTION_REG
continue
Name
SUMMARY OF WATCHDOG TIMER REGISTERS
WATCHDOG TIMER BLOCK DIAGRAM
WDT Timer
Enable Bit
WDT
with
RBPU
From TMR0 Clock Source
(Figure 5-1)
Bit 7
(1)
normal
BOREN
INTEDG
Bit 6
operation
0
1
(1)
PSA
M
U
X
T0CS
Bit 5
CP1
WDT time-out period values may be found in the Elec-
trical Specifications section under parameter #31. Val-
ues for the WDT prescaler (actually a postscaler, but
shared with the Timer0 prescaler) may be assigned
using the OPTION_REG register.
T0SE
Bit 4
CP0
0
Note 1: The CLRWDT and SLEEP instructions
Time-out
8 - to - 1 MUX
MUX
WDT
Postscaler
2: When a CLRWDT instruction is executed
PWRTEN
1
Bit 3
clear the WDT and the postscaler, if
assigned to the WDT, and prevent it from
timing out and generating a device
RESET condition.
and the prescaler is assigned to the WDT,
the prescaler count will be cleared, but
the prescaler assignment is not changed.
PSA
8
PIC16F870/871
(1)
PSA
To TMR0 (Figure 5-1)
WDTEN
Bit 2
PS2
PS2:PS0
FOSC1
Bit 1
PS1
DS30569B-page 99
FOSC0
Bit 0
PS0