UM10237_2 © NXP B.V. 2008. All rights reserved.
User manual Rev. 02 — 19 December 2008 153 o f 792
NXP Semiconductors UM10237
Chapter 8: LPC24XX Pin configuration
[1] 5 V tolerant pad providing digital I/O functions with TTL levels and hysteresis.
TCK 10[1] E2[1] ITCK — Test Clock for JTAG interface. This clock must be slower than 16
of the CPU clock (CCLK) for the JTAG interface to operate.
RTCK 206[1] C3[1] I/O RTCK — JTAG interface control signal.
Note: LOW on this pin while RESET is LOW enables ETM pins (P2[9:0])
to operate as Trace port after reset.
RSTOUT 29 K3 O RSTOUTThis is a 3.3 V pin. LOW on this pin indicates UM10237
being in Reset state.
RESET 35[7] M2[7] Iexternal 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. TTL with hysteresis, 5 V tolerant.
XTAL1 44[8] M4[8] I Input to the oscillator circuit and internal clock generator circuits.
XTAL2 46[8] N4[8] O Output from the oscillator amplifier.
RTCX1 34[8] K2[8] I Input to the RTC oscillator circuit.
RTCX2 36[8] L2[8] O Output from the RTC oscillator circuit.
VSSIO 33, 63,
77, 93,
114,
133,
148,
169,
189,
200[8]
L3, T5,
R9,
P12,
N16,
H14,
E15,
A12,
B6, A2[8]
Iground: 0 V reference for the digital I/O pins.
VSSCORE 32, 84,
172[8] K4, P10,
D12[8] Iground: 0 V reference for the core.
VSSA 22[8] J2[8] Ianalog ground: 0 V reference. This should nominally be the same
voltage as VSSIO/VSSCORE, but should be isolated to minimize noise and
error.
VDD(3V3) 15, 60,
71, 89,
112,
125,
146,
165,
181,
198[8]
G3,
P6, P8,
U13,
P17,
K16,
C17,
B13,
C9,
D7[8]
I3.3 V supply voltage: This is the power supply voltage for the I/O ports.
n.c. 30, 117,
141[8] J4, L14,
G14[8] Inot connected pins: These pins must be left unconnected (floating).
VDD(DCDC)(3V3) 26, 86,
174[8] H4, P11,
D11[8] I3.3V DC-to-DC conver ter supply voltage: This is the power supply for
the on-chip DC-to-DC converter.
VDDA 20[8] G4[8] Ianalog 3.3 V pad supply voltage: This should be nominally the same
voltage as VDD(3V3) but should be isolated to minimize noise and error.
This voltage is used to power the ADC and DAC.
VREF 24[8] K1[8] IADC reference: This should be nominally the same voltage as VDD(3V3)
but should be isolated to minimize noise and error. The level on this pin is
used as a reference for ADC and DAC.
VBAT 38[8] M3[8] IRTC power supply: 3.3V on this pin supplies the power to the RTC.
Table 122. LP C242 0/60/68 pin description …continued
Symbol Pin Ball Type Description