PIC16LF1526 Datasheet, PDF (128/354 Pages) Microchip Technology – 64-Pin Flash Microcontrollers with nanoWatt XLP Technology

PIC16(L)F1526/27
12.5 PORTD Registers
PORTD is a 8-bit wide, bidirectional port. The
corresponding data direction register is TRISD
(Register 12-7). Setting a TRISD bit (= 1) will make the
corresponding PORTD pin an input (i.e., put the
corresponding output driver in a High-Impedance mode).
Clearing a TRISD bit (= 0) will make the corresponding
PORTD 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 PORTD 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 (LATD).
The TRISD register (Register 12-7) controls the PORTD
pin output drivers, even when they are being used as
analog inputs. The user should ensure the bits in the
TRISD register are maintained set when using them as
analog inputs. I/O pins configured as analog input always
read ‘0’.
12.5.1 ANSELD REGISTER
The ANSELD register (Register 12-9) is used to
configure the Input mode of an I/O pin to analog.
Setting the appropriate ANSELD bit high will cause all
digital reads on the pin to be read as ‘0’ and allow
analog functions on the pin to operate correctly.
The state of the ANSELD bits has no effect on digital out-
put functions. A pin with TRIS clear and ANSELD set will
still operate as a digital output, but the Input mode will be
analog. This can cause unexpected behavior when exe-
cuting read-modify-write instructions on the affected
port.
Note:
The ANSELD bits default to the Analog
mode after Reset. To use any pins as
digital general purpose or peripheral
inputs, the corresponding ANSEL bits
must be initialized to ‘0’ by user software.
12.5.2
PORTD FUNCTIONS AND OUTPUT
PRIORITIES
Each PORTD pin is multiplexed with other functions. The
pins, their combined functions and their output priorities
are shown in Table 12-9.
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 override other port
functions and are included in Table 12-9.
TABLE 12-9: PORTD OUTPUT PRIORITY
Pin Name
Function Priority⁽¹⁾
RD0
RD0
RD1
RD1
RD2
RD2
RD3
RD3
RD4
SDO2
RD4
RD5
SDA2
RD5⁽²⁾
RD6
SCL2
SCK2
RD6⁽²⁾
RD7
RD7
Note 1: Priority listed from highest to lowest.
2: RD5 and RD6 read the I²C ST input when
I²C mode is enabled.
DS41458A-page 128
Preliminary
 2011 Microchip Technology Inc.