OM13008,598 NXP Semiconductors, OM13008,598 Datasheet - Page 293

• Manufacturer Part Number: OM13008,598
• Description: BOARD LPC XPRESSO LPC122X
• Manufacturer: NXP Semiconductors
• Series: LPCXpressor

Specifications of OM13008,598

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 568-6642; OM13008

NXP Semiconductors
UM10441
User manual
Fig 51. Comparator inputs
18.7.2 Reference voltages
18.7.3 Relaxation oscillator
C0_IN1
C0_IN2
C0_IN0
C0_IN3
VREF CMP
C1_IN0
C1_IN1
C1_IN2
C1_IN3
The comparator can use two reference voltages: the external reference voltage
VREF_CMP and the internal bandgap voltage, the BOD 0.9 V reference voltage. The
external reference voltage can be used with a programmable voltage ladder, which is
programmable in 32 levels from the VREF_CMP IO reference voltage down to VSS. The
maximum voltage for VREF_CMP is 3.3 V.
The digital circuitry includes a relaxation oscillator facility where the ROSC pin of the chip
can be routed externally back to the comparator input thereby creating oscillation that
could be used as a 555 timer.
The 555 has three operating modes:
Applications for the relaxation oscillator include precision timing, pulse generation,
sequential timing, time delay generation, pulse width generation, pulse position
generation, and missing pulse detection.
C0_IN4
C0_IN5
1. Monostable mode: in this mode, the 555 timer produces one single pulse. The pulse
2. Astable - free running mode: in this mode, the 555 timer produces a continuous
3. Bistable mode or Schmitt trigger: the 555 can operate as a flip-flop if the timing
C1_IN4
C1_IN5
width is configurable by an external RC network.
stream of rectangular pulses. The frequency of the oscillation is determined by two
external resistors and a capacitor.
capacitor pin is not connected and no capacitor is used.
(From BOD)
0.9 V
All information provided in this document is subject to legal disclaimers.
E X T E R N A L
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ANALOG LOGIC
Chapter 18: LPC122x Comparator
UM10441
© NXP B.V. 2011. All rights reserved.
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