Datasheet

PIC16(L)F1526/7
DS41458C-page 132  2011-2013 Microchip Technology Inc.
12.13 PORTF Registers
12.13.1 DATA REGISTER
PORTF is an 8-bit wide, bidirectional port. The
corresponding data direction register is TRISF
(Register 12-25). Setting a TRISF bit (= 1) will make the
corresponding PORTF pin an input (i.e., put the
corresponding output driver in a High-Impedance mode).
Clearing a TRISF bit (= 0) will make the corresponding
PORTF 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 PORTF register (Register 12-24) 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 (LATF).
12.13.2 DIRECTION CONTROL
The TRISF register (Register 12-25) controls the PORTF
pin output drivers, even when they are being used as
analog inputs. The user should ensure the bits in the
TRISF register are maintained set when using them as
analog inputs. I/O pins configured as analog input always
read ‘0’.
12.13.3 ANALOG CONTROL
The ANSELF register (Register 12-27) is used to
configure the Input mode of an I/O pin to analog.
Setting the appropriate ANSELF 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 ANSELF bits has no effect on digital out-
put functions. A pin with TRIS clear and ANSELF 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.
12.13.4 PORTE FUNCTIONS AND OUTPUT
PRIORITIES
Each PORTF pin is multiplexed with other functions. The
pins, their combined functions and their output priorities
are shown in Table 12-13.
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 the priority list.
Note: The ANSELF 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.
TABLE 12-13: PORTF OUTPUT PRIORITY
Pin Name Function Priority
(1)
RF0 VCAP
(2)
RF0
RF1 RF1
RF2 RF2
RF3 RF3
RF4 RF4
RF5 RF5
RF6 RF6
RF7 RF7
Note 1: Priority listed from highest to lowest.
2: PIC16F1526/7 only