PIC12CE518-04SM Datasheet, PDF (23/113 Pages) Microchip Technology – 8-Pin, 8-Bit CMOS Microcontrollers

PIC12C5XX
FIGURE 5-2: SUCCESSIVE I/O OPERATION
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
Instruction
fetched
PC
MOVWF GPIO
PC + 1
MOVF GPIO,W
PC + 2
NOP
PC + 3
NOP
GP5:GP0
Instruction
executed
Port pin
written here
Port pin
sampled here
MOVWF GPIO
(Write to
GPIO)
MOVF GPIO,W
(Read
GPIO)
NOP
This example shows a write to GPIO followed
by a read from GPIO.
Data setup time = (0.25 TCY – TPD)
where: TCY = instruction cycle.
TPD = propagation delay
Therefore, at higher clock frequencies, a
write followed by a read may be problematic.
© 1999 Microchip Technology Inc.
DS40139E-page 23