LPC2925 NXP Semiconductors, LPC2925 Datasheet - Page 40

• Manufacturer Part Number: LPC2925
• Description: (LPC2921 - LPC2925) ARM9 microcontroller
• Manufacturer: NXP Semiconductors

NXP Semiconductors
LPC2921_2923_2925_0
Preliminary data sheet
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6.14.7.1 Pin description
6.14.7.2 Clock description
6.15 Power, clock, and Reset control Sub System (PCRSS)
The QEI has the following features:
The QEI module in the MSCSS has the following pins. These are combined with other
functions on the port pins of the LPC2921/2923/2925.
Table 23.
Remark: The index function for the QEI is not pinned out on the LPC2921/2923/2925.
The QEI module is clocked by CLK_MSCSS_QEI, see
this clock is identical to CLK_MSCSS_APB since they are derived from the same base
clock BASE_MSCSS_CLK.
If the QEI is not used its CLK_MSCSS_QEI branch clock can be switched off.
The Power, Clock, and Reset Control Subsystem (PCRSS) in the LPC2921/2923/2925
includes a Clock Generator Unit (CGU), a Reset Generator Unit (RGU) and a Power
Management Unit (PMU).
Figure 8
communication with the AHB system bus.
Symbol
QEI0 PHA
QEI0 PHB
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Tracks encoder position.
Increments/ decrements depending on direction.
Programmable for 2X or 4X position counting.
Velocity capture using built-in timer.
Velocity compare function with less than interrupt.
Uses 32-bit registers for position and velocity.
Three position compare registers with interrupts.
Index counter for revolution counting.
Index compare register with interrupts.
Can combine index and position interrupts to produce an interrupt for whole and
partial revolution displacement.
Digital filter with programmable delays for encoder input signals.
Can accept decoded signal inputs (clk and direction).
Connected to APB.
provides an overview of the PCRSS. An AHB-to-DTL bridge controls the
QEI pins
PHA0
PHB0
Pin name
Rev. 00.01 — 24 October 2008
Direction
IN
IN
Description
Sensor signal. Corresponds to PHA in
quadrature mode and to direction in
clock/direction mode.
Sensor signal. Corresponds to PHB in
quadrature mode and to clock signal in
clock/direction mode.
ARM9 microcontroller with CAN and LIN
LPC2921/2923/2925
Table 23
Section
6.7.2. The frequency of
shows the QEI pins.
© NXP B.V. 2008. All rights reserved.
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