NXP Semiconductors LPC1768 User Manual

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User manual Rev. 3 — 19 December 2013 551 of 841
NXP Semiconductors
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Chapter 26: LPC176x/5x Quadrature Encoder Interface (QEI)
26.6.2 Control registers
26.6.2.1 QEI Control register (QEICON - 0x400B C000)
This register contains bits which control the operation of the position and velocity counters
of the QEI module.
26.6.2.2 QEI Configuration register (QEICONF - 0x400B C008)
This register contains the configuration of the QEI module.
26.6.2.3 QEI Status register (QEISTAT - 0x400B C004)
This register provides the status of the encoder interface.
Table 484: QEI Control register (QEICON - address 0x400B C000) bit description
Bit Symbol Description Reset
value
0 RESP Reset position counter. When set = 1, resets the position counter to all zeros. Autoclears when
the position counter is cleared.
0
1 RESPI Reset position counter on index. When set = 1, resets the position counter to all zeros when an
index pulse occurs. Autoclears when the position counter is cleared.
0
2 RESV Reset velocity. When set = 1, resets the velocity counter to all zeros and reloads the velocity
timer. Autoclears when the velocity counter is cleared.
0
3 RESI Reset index counter. When set = 1, resets the index counter to all zeros. Autoclears when the
index counter is cleared.
0
31:4 - reserved 0
Table 485: QEI Configuration register (QEICONF - address 0x400B C008) bit description
Bit Symbol Description Reset
value
0 DIRINV Direction invert. When = 1, complements the DIR bit. 0
1 SIGMODE Signal Mode. When = 0, PhA and PhB function as quadrature encoder inputs. When = 1, PhA
functions as the direction signal and PhB functions as the clock signal.
0
2 CAPMODE Capture Mode. When = 0, only PhA edges are counted (2X). When = 1, BOTH PhA and PhB
edges are counted (4X), increasing resolution but decreasing range.
0
3 INVINX Invert Index. When set, inverts the sense of the index input. 0
31:4 - reserved 0
Table 486: QEI Interrupt Status register (QEISTAT - address 0x400B C004) bit description
Bit Symbol Description Reset
value
0 DIR Direction bit. In combination with DIRINV bit indicates forward or reverse direction. See
Table 481
.
31:1 - reserved 0

NXP Semiconductors LPC1768 Specifications

General

Brand	NXP Semiconductors
Model	LPC1768
Category	Microcontrollers
Language	English