Microchip Technology MA300015 Data Sheet

© 2011 Microchip Technology Inc.

DS70150E-page 91

This section describes the Quadrature Encoder Inter-
face (QEI) module and associated operational modes.
The QEI module provides the interface to incremental
encoders for obtaining mechanical position data. 

The operational features of the QEI include:

• Three input channels for two phase signals and 

index pulse

• 16-bit up/down position counter

• Count direction status

• Position Measurement (x2 and x4) mode

• Programmable digital noise filters on inputs

• Alternate 16-bit Timer/Counter mode

• Quadrature Encoder Interface interrupts

These operating modes are determined by setting the
appropriate bits, QEIM<2:0> (QEICON<10:8>).

 depicts the Quadrature Encoder Interface

block diagram.

This data sheet summarizes features of
this group of dsPIC30F devices and is not
intended to be a complete reference
source. For more information on the CPU,
peripherals, register descriptions and
general device functionality, refer to the
“dsPIC30F Family Reference Manual”
(DS70046).

16-bit Up/Down Counter

Comparator/

Max Count Register

Quadrature

Programmable

Digital Filter

    QEA

Programmable

Digital Filter

     INDX

0

1

Up/Down

Existing Pin Logic

   UPDN

3

Encoder

Programmable

Digital Filter

    QEB

Interface Logic

QEIM<2:0>

     Mode Select

3

(POSCNT)

(MAXCNT)

PCDOUT

QEIIF
Event 
Flag

Reset

Equal

2

T

CY

1

0

 TQCS

    TQCKPS<1:0>

2

 1, 8, 64, 256

 Prescaler

Q

Q

D

CK

TQGATE

QEIM<2:0>

   

Synchronize

Det

1

0

Sleep Input

0

1

UPDN_SRC

QEICON<11>

Zero Detect