PIC16LF1946_13 Datasheet, PDF (133/478 Pages) Microchip Technology – 64-Pin Flash-Based, 8-Bit CMOS Microcontrollers with LCD Driver and nanoWatt XLP Technology

12.5 PORTB Registers
PORTB is an 8-bit wide, bidirectional port. The
corresponding data direction register is TRISB
(Register 12-7). 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., enable the output driver and
put the contents of the output latch on the selected pin).
Example 12-1 shows how to initialize an I/O port.
Reading the PORTB register (Register 12-6) reads the
status of the pins, whereas writing to it will write to the
PORT latch. All write operations are read-modify-write
operations. Therefore, a write to a port implies that the
port pins are read, this value is modified and then written
to the PORT data latch (LATB).
The TRISB register (Register 12-7) controls the PORTB
pin output drivers, even when they are being used as
analog inputs. The user should ensure the bits in the
TRISB register are maintained set when using them as
analog inputs. I/O pins configured as analog inputs
always read ‘0’.
12.5.1 WEAK PULL-UPS
Each of the PORTB pins has an individually configurable
internal weak pull-up. Control bits WPUB<7:0> enable or
disable each pull-up (see Register 12-9). Each weak
pull-up is automatically turned off when the port pin is
configured as an output. All pull-ups are disabled on a
Power-on Reset by the WPUEN bit of the OPTION_REG
register.
12.5.2 INTERRUPT-ON-CHANGE
All of the PORTB pins are individually configurable as
an interrupt-on-change pin. Control bits IOCB<7:0>
enable or disable the interrupt function for each pin.
The interrupt-on-change feature is disabled on a
Power-on Reset. Reference Section 13.0
“Interrupt-On-Change” for more information.
PIC16(L)F1946/47
12.5.3 PORTB FUNCTIONS AND OUTPUT
PRIORITIES
Each PORTB pin is multiplexed with other functions. The
pins, their combined functions and their output priorities
are shown in Table 12-5.
When multiple outputs are enabled, the actual pin
control goes to the peripheral with the highest priority.
Analog input and some digital input functions are not
included in the list below. These input functions can
remain active when the pin is configured as an output.
Certain digital input functions, such as the EUSART RX
signal, override other port functions and are included in
the priority list.
TABLE 12-5: PORTB OUTPUT PRIORITY
Pin
Name
Function Priority⁽¹⁾
RB0 SEG12 (LCD)
SRI (SR Latch)
RB0
RB1 SEG8 (LCD)
RB1
RB2 SEG9 (LCD)
RB2
RB3 SEG10 (LCD)
RB3
RB4 SEG11 (LCD)
RB4
RB5 SEG29 (LCD)
RB5
RB6 ICSPCLK (Programming)
ICDCLK (enabled by Configuration Word)
SEG38 (LCD)
RB6
RB7 ICSPDAT (Programming)
ICDDAT (enabled by Configuration Word)
SEG39 (LCD)
RB7
Note 1: Priority listed from highest to lowest.
 2010-2012 Microchip Technology Inc.
DS41414D-page 133