PIC18F2331-E/ML MICROCHIP [Microchip Technology], PIC18F2331-E/ML Datasheet - Page 165

• Manufacturer Part Number: PIC18F2331-E/ML
• Description: 28/40/44-Pin Enhanced Flash Microcontrollers with nanoWatt Technology, High-Performance PWM and A/D
• Manufacturer: MICROCHIP [Microchip Technology]

FIGURE 17-9:
FIGURE 17-10:
 2010 Microchip Technology Inc.
Note 1: The POSCNT register is shown in QEI x4 Update mode (POSCNT increments on every rising and every falling edge
Note 1: The module design allows a quadrature frequency of up to F
T
QEA Pin
QEB Pin
QEA Input
QEB Input
CY
2: When POSCNT = MAXCNT, POSCNT is reset to ‘0’ on the next QEA rising edge. POSCNT is set to MAXCNT when
3: IC2QEIF is generated on the Q4 rising edge.
4: Position counter is loaded with ‘0’ (which is a rollover event in this case) on POSCNT = MAXCNT.
5: Position counter is loaded with MAXCNT value (1527h) on underflow.
6: IC2QEIF must be cleared in software.
QEA
QEB
Count (+/-)
POSCNT
MAXCNT
IC2QEIF
UP/DOWN
Position
Counter Load
IC3DRIF
of QEA and QEB input signals). Asynchronous external QEA and QEB inputs are synchronized to the T
the input sampling FF in the noise filter (see
POSCNT = 0 (when decrementing), which occurs on the next QEA falling edge.
(1)
T
GD
QEI INPUTS WHEN SAMPLED BY THE FILTER (DIVIDE RATIO = 1:1)
QEI MODULE RESET TIMING ON PERIOD MATCH
+1 +1 +1 +1 +1 +1 +1 +1 +1 +1 +1 +1
MAXCNT=1527
= 3 T
CY
Note 2
Q1
Q4
Forward
(4)
(3)
T
QEI
PIC18F2331/2431/4331/4431
= 16 T
Q1
CY
(5)
Figure
(1)
-1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1
Note 6
Note 2
Q1
17-14).
Q4
(5)
(3)
Reverse
QEI
= F
CY
/16.
DS39616D-page 165
CY
clock by