PIC16LF1508 Datasheet, PDF (111/384 Pages) Microchip Technology – 20-Pin Flash, 8-Bit Microcontrollers with nanoWatt XLP Technology

11.0 I/O PORTS
Each port has three standard registers for its operation.
These registers are:
• TRISx registers (data direction)
• PORTx registers (reads the levels on the pins of
the device)
• LATx registers (output latch)
Some ports may have one or more of the following
additional registers. These registers are:
• ANSELx (analog select)
• WPUx (weak pull-up)
In general, when a peripheral is enabled on a port pin,
that pin cannot be used as a general purpose output.
However, the pin can still be read.
TABLE 11-1: PORT AVAILABILITY PER
DEVICE
Device
PIC16(L)F1508/9
●
●
●
The Data Latch (LATx registers) is useful for
read-modify-write operations on the value that the I/O
pins are driving.
A write operation to the LATx register has the same
effect as a write to the corresponding PORTx register.
A read of the LATx register reads of the values held in
the I/O PORT latches, while a read of the PORTx
register reads the actual I/O pin value.
Ports that support analog inputs have an associated
ANSELx register. When an ANSEL bit is set, the digital
input buffer associated with that bit is disabled.
Disabling the input buffer prevents analog signal levels
on the pin between a logic high and low from causing
excessive current in the logic input circuitry. A
simplified model of a generic I/O port, without the
interfaces to other peripherals, is shown in Figure 11-1.
PIC16(L)F1508/9
FIGURE 11-1:
GENERIC I/O PORT
OPERATION
Read LATx _TRISx
Write LATx
Write PORTx
D
Q
CK
Data Register
Data Bus
Read PORTx
To peripherals
ANSELx
VDD
I/O pin
VSS
 2011 Microchip Technology Inc.
Preliminary
DS41609A-page 111