Datasheet

© 2011 Microchip Technology Inc. DS70118J-page 75
dsPIC30F2010
13.0 QUADRATURE ENCODER
INTERFACE (QEI) MODULE
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 motor positioning data. Incre-
mental encoders are very useful in motor control
applications.
The Quadrature Encoder Interface (QEI) is a key fea-
ture requirement for several motor control applications,
such as Switched Reluctance (SR) and AC Induction
Motor (ACIM). The operational features of the QEI are,
but not limited to:
• 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>).
Figure 13-1 depicts the Quadrature Encoder Interface
block diagram.
FIGURE 13-1: QUADRATURE ENCODER INTERFACE BLOCK DIAGRAM
Note: 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
3
Encoder
Programmable
Digital Filter
QEB
Interface Logic
QEIM<2:0>
Mode Select
3
(POSCNT)
(MAXCNT)
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