PIC16F876A-E/ML Microchip Technology, PIC16F876A-E/ML Datasheet - Page 46
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PIC16F876A-E/ML
Manufacturer Part Number
PIC16F876A-E/ML
Description
IC MCU FLASH 8KX14 A/D 28QFN
Manufacturer
Microchip Technology
Series
PIC® 16Fr
Datasheets
1.PIC16F616T-ISL.pdf
(8 pages)
2.PIC16F688T-ISL.pdf
(688 pages)
3.PIC16C770-ISO.pdf
(8 pages)
4.PIC16F873A-ISO.pdf
(234 pages)
5.PIC16F873A-ISO.pdf
(6 pages)
6.PIC16F873A-ISO.pdf
(4 pages)
7.PIC16F873A-ISO.pdf
(6 pages)
8.PIC16F873A-ISO.pdf
(4 pages)
9.PIC16F873A-ISO.pdf
(22 pages)
Specifications of PIC16F876A-E/ML
Core Processor
PIC
Core Size
8-Bit
Speed
20MHz
Connectivity
I²C, SPI, UART/USART
Peripherals
Brown-out Detect/Reset, POR, PWM, WDT
Number Of I /o
22
Program Memory Size
14KB (8K x 14)
Program Memory Type
FLASH
Eeprom Size
256 x 8
Ram Size
368 x 8
Voltage - Supply (vcc/vdd)
4 V ~ 5.5 V
Data Converters
A/D 5x10b
Oscillator Type
External
Operating Temperature
-40°C ~ 125°C
Package / Case
28-VQFN Exposed Pad, 28-HVQFN, 28-SQFN, 28-DHVQFN
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Part Number:
PIC16F876A-E/ML
Manufacturer:
MICROCHIP/微芯
Quantity:
20 000
PIC16F87XA
4.2
PORTB is an 8-bit wide, bidirectional port. The corre-
sponding data direction register is TRISB. Setting a
TRISB bit (= 1) will make the corresponding PORTB
pin an input (i.e., put the corresponding output driver in
a High-Impedance mode). Clearing a TRISB bit (= 0)
will make the corresponding PORTB pin an output (i.e.,
put the contents of the output latch on the selected pin).
Three pins of PORTB are multiplexed with the In-Circuit
Debugger and Low-Voltage Programming function:
RB3/PGM, RB6/PGC and RB7/PGD. The alternate
functions of these pins are described in Section 14.0
“Special Features of the CPU”.
Each of the PORTB pins has a weak internal pull-up. A
single control bit can turn on all the pull-ups. This is per-
formed by clearing bit RBPU (OPTION_REG<7>). The
weak pull-up is automatically turned off when the port
pin is configured as an output. The pull-ups are
disabled on a Power-on Reset.
FIGURE 4-4:
Four of the PORTB pins, RB7:RB4, have an interrupt-
on-change feature. Only pins configured as inputs can
cause this interrupt to occur (i.e., any RB7:RB4 pin
configured as an output is excluded from the interrupt-
on-change comparison). The input pins (of RB7:RB4)
are compared with the old value latched on the last
read of PORTB. The “mismatch” outputs of RB7:RB4
are OR’ed together to generate the RB port change
interrupt with flag bit RBIF (INTCON<0>).
DS39582B-page 44
Note 1: I/O pins have diode protection to V
RBPU
Data Bus
WR Port
WR TRIS
RD TRIS
RD Port
RB0/INT
RB3/PGM
2: To enable weak pull-ups, set the appropriate TRIS
(2)
PORTB and the TRISB Register
bit(s) and clear the RBPU bit (OPTION_REG<7>).
TRIS Latch
Data Latch
D
D
CK
CK
Schmitt Trigger
Buffer
BLOCK DIAGRAM OF
RB3:RB0 PINS
Q
Q
Q
EN
D
TTL
Input
Buffer
DD
and V
V
RD Port
P
DD
I/O pin
Weak
Pull-up
SS
.
(1)
This interrupt can wake the device from Sleep. The
user, in the Interrupt Service Routine, can clear the
interrupt in the following manner:
a)
b)
A mismatch condition will continue to set flag bit RBIF.
Reading PORTB will end the mismatch condition and
allow flag bit RBIF to be cleared.
The interrupt-on-change feature is recommended for
wake-up on key depression operation and operations
where PORTB is only used for the interrupt-on-change
feature. Polling of PORTB is not recommended while
using the interrupt-on-change feature.
This interrupt-on-mismatch feature, together with soft-
ware configurable pull-ups on these four pins, allow
easy interface to a keypad and make it possible for
wake-up on key depression. Refer to the application
note, AN552, “Implementing Wake-up on Key Stroke”
(DS00552).
RB0/INT is an external interrupt input pin and is
configured using the INTEDG bit (OPTION_REG<6>).
RB0/INT is discussed in detail in Section 14.11.1 “INT
Interrupt”.
FIGURE 4-5:
Note 1: I/O pins have diode protection to V
RBPU
Data Bus
WR Port
WR TRIS
RD TRIS
RD Port
Set RBIF
RB7:RB6
In Serial Programming Mode
Any read or write of PORTB. This will end the
mismatch condition.
Clear flag bit RBIF.
From other
RB7:RB4 pins
2: To enable weak pull-ups, set the appropriate TRIS
(2)
bit(s) and clear the RBPU bit (OPTION_REG<7>).
TRIS Latch
Data Latch
D
D
CK
CK
Q
Q
BLOCK DIAGRAM OF
RB7:RB4 PINS
2003 Microchip Technology Inc.
Q
Q
Latch
EN
EN
D
D
TTL
Input
Buffer
DD
and V
V
P
DD
Weak
Pull-up
RD Port
I/O pin
SS
Buffer
.
Q1
Q3
ST
(1)