PIC16F74T-I/L Microchip Technology, PIC16F74T-I/L Datasheet - Page 35
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PIC16F74T-I/L
Manufacturer Part Number
PIC16F74T-I/L
Description
IC MCU FLASH 4KX14 A/D 44PLCC
Manufacturer
Microchip Technology
Series
PIC® 16Fr
Datasheets
1.PIC16F616T-ISL.pdf
(8 pages)
2.PIC16F688T-ISL.pdf
(688 pages)
3.PIC16F818-ISO.pdf
(6 pages)
4.PIC16F73-ISP.pdf
(174 pages)
5.PIC16F73-ISP.pdf
(14 pages)
6.PIC16F73-ISP.pdf
(12 pages)
Specifications of PIC16F74T-I/L
Core Size
8-Bit
Program Memory Size
7KB (4K x 14)
Peripherals
Brown-out Detect/Reset, POR, PWM, WDT
Core Processor
PIC
Speed
20MHz
Connectivity
I²C, SPI, UART/USART
Number Of I /o
33
Program Memory Type
FLASH
Ram Size
192 x 8
Voltage - Supply (vcc/vdd)
4 V ~ 5.5 V
Data Converters
A/D 8x8b
Oscillator Type
External
Operating Temperature
-40°C ~ 85°C
Package / Case
44-PLCC
Controller Family/series
PIC16F
No. Of I/o's
33
Ram Memory Size
192Byte
Cpu Speed
20MHz
No. Of Timers
3
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
For Use With
DVA16XL441 - ADAPTER DEVICE ICE 44PLCC
Eeprom Size
-
Lead Free Status / RoHS Status
Lead free / RoHS Compliant, Lead free / RoHS Compliant
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
PIC16F74T-I/L
Manufacturer:
Microchip Technology
Quantity:
10 000
4.2
PORTB is an 8-bit wide, bi-directional 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 Hi-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).
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 dis-
abled on a Power-on Reset.
FIGURE 4-3:
Four of the PORTB pins (RB7:RB4) have an inter-
rupt-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 inter-
rupt-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 ORed together to generate the RB Port
Change Interrupt with flag bit RBIF (INTCON<0>).
2002 Microchip Technology Inc.
Note 1: I/O pins have diode protection to V
RBPU
Data Bus
WR Port
WR TRIS
RD TRIS
RD Port
RB0/INT
2: To enable weak pull-ups, set the appropriate TRIS
PORTB and the TRISB Register
(2)
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
TTL
Input
Buffer
D
DD
and V
V
RD Port
P
DD
SS
Weak
Pull-up
.
pin
I/O
(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 configureable 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 Embedded
Control Handbook, “Implementing Wake-up on Key
Stroke” (AN552).
RB0/INT is an external interrupt input pin and is config-
ured using the INTEDG bit (OPTION_REG<6>).
RB0/INT is discussed in detail in Section 12.11.1.
FIGURE 4-4:
Note 1: I/O pins have diode protection to V
Set RBIF
RBPU
Data Bus
WR Port
WR TRIS
RD TRIS
RD Port
RB7:RB6 in Serial Programming mode
Any read or write of PORTB. This will end the
mismatch condition.
Clear flag bit RBIF.
2: To enable weak pull-ups, set the appropriate TRIS bit(s)
From other
RB7:RB4 pins
(2)
and clear the RBPU bit (OPTION_REG<7>).
Data Latch
TRIS Latch
D
D
CK
CK
Q
Q
BLOCK DIAGRAM OF
RB7:RB4 PINS
PIC16F7X
Q
Q
Latch
EN
EN
D
D
DD
DS30325B-page 33
TTL
Input
Buffer
and V
V
P
DD
SS
Weak
Pull-up
RD Port
.
Buffer
pin
I/O
Q1
Q3
ST
(1)