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UM10360_0
© NXP B.V. 2009. All rights reserved.
User manual
Rev. 00.06 — 5 June 2009
75 of 808
NXP Semiconductors
UM10360
Chapter 7: LPC17xx Pin configuration
[1]
Pad provides special analog functionality.
RSTOUT
14
11
O
RSTOUT —
This is a 3.3 V pin. A LOW on this pin indicates that the
LPC17xx is in a Reset state.
RESET
17
14
I
External reset input:
A LOW on this pin resets the device, causing I/O
ports and peripherals to take on their default states, and processor
execution to begin at address 0. This is a 5 V tolerant pad with a 20 ns
glitch filter, TTL levels and hysteresis.
XTAL1
22
I
Input to the oscillator circuit and internal clock generator circuits.
XTAL2
23
O
Output from the oscillator amplifier.
RTCX1
16
I
Input to the RTC oscillator circuit.
RTCX2
18
O
Output from the RTC oscillator circuit.
V
SS
31, 41,
55, 72,
83, 97
24, 33,
43, 57,
66, 78
I
ground:
0 V reference.
V
SSA
11
I
analog ground:
0 V reference. This should be the same voltage as V
SS
,
but should be isolated to minimize noise and error.
V
DD(3V3)
28, 54,
71, 96
21, 42,
56, 77
I
3.3 V supply voltage:
This is the power supply voltage for I/O other than
pins in the Vbat domain.
V
DD(REG)(3V3)
42, 84
34, 67
I
3.3 V voltage regulator supply voltage:
This is the supply voltage for the
on-chip voltage regulator only.
V
DDA
10
I
analog 3.3 V pad supply voltage:
This can be connected to the same
supply as V
DD(3V3)
but should be isolated to minimize noise and error. This
voltage is used to power the ADC and DAC.
Note: this pin should be tied
to 3.3v if the ADC and DAC are not used.
V
REFP
12
I
ADC positive reference voltage:
This should be nominally the same
voltage as V
DDA
but should be isolated to minimize noise and error. The
voltage level on this pin is used as a reference for ADC and DAC.
Note:
this pin should be tied to 3.3v if the ADC and DAC are not used.
V
REFN
15
I
ADC negative reference voltage:
This should be the same voltage as
V
SS
but should be isolated to minimize noise and error. Level on this pin is
used as a reference for ADC and DAC.
V
BAT
19
I
RTC domain power supply:
3.3 V on this pin supplies the power to the
RTC peripheral.
n.c.
13
-
-
not connected
Table 51.
Pin description
…continued
Symbol
LQFP
100
LQFP
80
Type Description