Datasheet

 2013 Microchip Technology Inc. DS22331A-page 109
MCP19111
19.0 I/O PORTS
In general, when a peripheral is enabled, that pin may
not be used as a general purpose I/O pin.
Each port has two registers for its operation. These
registers are:
• TRISx registers (data direction register)
• PORTGPx registers (reads the levels on the pins
of the device)
Some ports may have one or more of the following
additional registers. These registers are:
• ANSELx (analog select)
• WPUx (weak pull-up)
Ports with analog functions also have an ANSELx
register, which can disable the digital input and save
power. A simplified model of a generic I/O port, without
the interfaces to other peripherals, is shown in
Figure 19-1.
FIGURE 19-1: GENERIC I/O PORTGPX
OPERATION
EXAMPLE 19-1: INITIALIZING PORTA
QD
CK
Write LATx
Data Register
I/O pin
Read PORTx
Write PORTx
TRISx
Read LATx
Data Bus
To peripherals
ANSELx
V
DD
V
SS
; This code example illustrates
; initializing the PORTGPA register. The
; other ports are initialized in the same
; manner.
BANKSEL PORTGPA;
CLRF PORTGPA;Init PORTA
BANKSEL ANSELA;
CLRF ANSELA;digital I/O
BANKSEL TRISGPA;
MOVLW B'00011111';Set GPA<4:0> as
;inputs
MOVWF TRISGPA;and set GPA<7:6> as
;outputs