PIC16F872-I/SP Microchip Technology Inc., PIC16F872-I/SP Datasheet - Page 93

• Manufacturer Part Number: PIC16F872-I/SP
• Description: 28 PIN, 7 KB FLASH, 128 RAM, 22 I/O
• Manufacturer: Microchip Technology Inc.

Specifications of PIC16F872-I/SP

• A/d Inputs: 5-Channel, 10-Bit
• Cpu Speed: 5 MIPS
• Eeprom Memory: 64 Bytes
• Input Output: 22
• Interface: I2C/SPI
• Memory Type: Flash
• Number Of Bits: 8
• Package Type: 28-pin SPDIP
• 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 PIC16F872 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:
© 2006 Microchip Technology Inc.
MCLR
OSC1
V
Note 1: This is a separate oscillator from the RC oscillator of the CLKIN pin.
DD
Reset
RC OSC
On-Chip
OST/PWRT
Brown-out
V
(1)
Module
Detect
DD
WDT
Reset
Rise
OST
PWRT
SIMPLIFIED BLOCK DIAGRAM OF ON-CHIP RESET CIRCUIT
Time-out
Reset
WDT
10-bit Ripple Counter
10-bit Ripple Counter
BODEN
Power-on Reset
External
RESET
SLEEP
Enable PWRT
Enable OST
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.
PIC16F872
S
R
DS30221C-page 91
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Chip_Reset