PIC17C752 MICROCHIP [Microchip Technology], PIC17C752 Datasheet - Page 78

• Manufacturer Part Number: PIC17C752
• Description: High-Performance 8-Bit CMOS EPROM Microcontrollers
• Manufacturer: MICROCHIP [Microchip Technology]

10.6
PORTF is an 8-bit wide bi-directional port. The corre-
sponding data direction register is DDRF. A '1' in DDRF
configures the corresponding port pin as an input. A '0'
in the DDRF register configures the corresponding port
pin as an output. Reading PORTF reads the status of
the pins, whereas writing to them will write to the
respective port latch.
All eight bits of PORTF are multiplexed with 8 of the 12
channels of the 10-bit A/D converter.
Upon reset the entire Port is automatically configured
as analog inputs, and must be configured in software to
be a digital I/O.
FIGURE 10-13: BLOCK DIAGRAM OF RF7:RF0
DS30264A-page 78
WR PORTF
WR DDRF
RD PORT
V
Data bus
AN
PORTF and DDRF Registers
PCFG3:PCFG0
CHS3:CHS0
Data Latch
DDRF Latch
D
CK
D
CK
RD DDRF
Q
Q
Q
Q
Q
Preliminary
EN
EN
D
To other pads
To other pads
Example 10-6 shows an instruction sequence to initial-
ize PORTF. The Bank Select Register (BSR) must be
selected to Bank 5 for the port to be initialized. The fol-
lowing example uses the MOVLB instruction to load the
BSR register for bank selection.
EXAMPLE 10-6: INITIALIZING PORTF
MOVLB
MOVLW
MOVPF
CLRF
MOVLW
MOVWF
5
0x0E
ADCON1 ; Digital
PORTF
0x03
DDRF
V
V
P
N
DD
SS
; Select Bank 5
; Configure PORTF as
; Initialize PORTF data
;
;
;
; Value used to initialize
;
; Set RF<1:0> as inputs
;
1997 Microchip Technology Inc.
latches before setting
the data direction
register
data direction
RF<7:2> as outputs
ST
input
buffer
I/O pin