PIC17C75X Datasheet, PDF (66/320 Pages) Microchip Technology – High-Performance 8-Bit CMOS EPROM Microcontrollers

PIC17C75X
Example 10-1 shows an instruction sequence to initial-
ize PORTA. The Bank Select Register (BSR) must be
selected to Bank 0 for the port to be initialized. The fol-
lowing example uses the MOVLB instruction to load the
BSR register for bank selection.
EXAMPLE 10-1: INITIALIZING PORTA
MOVLB
MOVLW
MOVPF
0
0xF3
PORTA
; Select Bank 0
;
; Initialize PORTA
; RA<3:2> are output low
; RA<5:4> and RA<1:0>
; are inputs
; (outputs floating)
FIGURE 10-2: RA2 BLOCK DIAGRAM
Peripheral data in
D
Q
Data Bus
EN
Q
D
RD_PORTA
(Q2)
1
Q CK
0
WR_PORTA
(Q4)
SCL out
I²C Mode enable
Note: I/O pin has protection diodes to VSS.
FIGURE 10-3: RA3 BLOCK DIAGRAM
Peripheral data in
D
Q
Data Bus
EN
Q
D
RD_PORTA
(Q2)
Q CK
“1”
WR_PORTA
(Q4)
SDA out
SSP Mode
Note: I/O pin has protection diodes to VSS.
FIGURE 10-4: RA4 AND RA5 BLOCK
DIAGRAM
Serial port input signal
Data Bus
RD_PORTA
(Q2)
Serial port output signals
OE = SPEN,SYNC,TXEN, CREN, SREN for RA4
OE = SPEN (SYNC+SYNC,CSRC) for RA5
Note: I/O pins have protection diodes to VDD and VSS.
DS30264A-page 66
Preliminary
© 1997 Microchip Technology Inc.