PIC16F871-I/PT Microchip Technology Inc., PIC16F871-I/PT Datasheet - Page 93

• Manufacturer Part Number: PIC16F871-I/PT
• Description: 44 PIN, 7 KB FLASH, 128 RAM, 33 I/O
• Manufacturer: Microchip Technology Inc.

Specifications of PIC16F871-I/PT

• A/d Inputs: 8-Channel, 10-Bit
• Cpu Speed: 5 MIPS
• Eeprom Memory: 64 Bytes
• Input Output: 33
• Interface: USART
• Memory Type: Flash
• Number Of Bits: 8
• Package Type: 44-pin TQFP
• Programmable Memory: 3.5K Bytes
• Ram Size: 128 Bytes
• Speed: 20 MHz
• Timers: 2-8-bit, 1-16-bit
• Voltage, Range: 2-5.5 V
• Lead Free Status / Rohs Status: RoHS Compliant part Electrostatic Device

11.3
The PIC16F870/871 differentiates between various
kinds of RESET:
• Power-on Reset (POR)
• MCLR Reset during normal operation
• MCLR Reset during SLEEP
• WDT Reset (during normal operation)
• WDT Wake-up (during SLEEP)
• Brown-out Reset (BOR)
Some registers are not affected in any RESET condi-
tion. Their status is unknown on POR and unchanged
in any other RESET. Most other registers are reset to a
“RESET state” on Power-on Reset (POR), on the
MCLR and WDT Reset, on MCLR Reset during
FIGURE 11-4:
 2003 Microchip Technology Inc.
MCLR
OSC1
V
DD
Note 1: This is a separate oscillator from the RC oscillator of the CLKI pin.
RESET
RC OSC
On-chip
OST/PWRT
Brown-out
V
(1)
Module
Detect
DD
WDT
Reset
Rise
SIMPLIFIED BLOCK DIAGRAM OF ON-CHIP RESET CIRCUIT
OST
PWRT
WDT
Time-out
Reset
10-bit Ripple Counter
10-bit Ripple Counter
BOREN
Power-on Reset
External
RESET
SLEEP
SLEEP, and Brown-out Reset (BOR). They are not
affected by a WDT Wake-up, which is viewed as the
resumption of normal operation. The TO and PD bits
are set or cleared differently in different RESET situa-
tions, as indicated in Table 11-4. These bits are used in
software to determine the nature of the RESET. See
Table 11-6 for a full description of RESET states of all
registers.
A simplified block diagram of the On-Chip Reset Circuit
is shown in Figure 11-4.
These devices have a MCLR noise filter in the MCLR
Reset path. The filter will detect and ignore small
pulses.
It should be noted that a WDT Reset does not drive
MCLR pin low.
PIC16F870/871
S
R
DS30569B-page 91
Q
Enable PWRT
Enable OST
Chip_Reset