UM10237_2 © NXP B.V. 2008. All rights reserved.
User manual Rev. 02 — 19 December 2008 134 o f 792
NXP Semiconductors UM10237
Chapter 8: LPC24XX Pin configuration
P4[24]/OE C8[1] I/O P4[24] — General purpose digital input/output pin.
OOELOW active Output Enable signal.
P4[25]/WE D9[1] I/O P4[25] — General purpose digital input/output pin.
OWELOW active Write Enable signal.
P4[26]/BLS0 K13[1] I/O P4[26] — General purpose digital input/output pin.
OBLS0 — LOW active Byte Lane select signal 0.
P4[27]/BLS1 F14[1] I/O P4[27] — General purpose digital input/output pin.
OBLS1 — LOW active Byte Lane select signal 1.
P4[28]/MAT2[0]/
TXD3 D10[1] I/O P4[28] — General purpose digital input/output pin.
OMAT2[0] — Match output for Timer2 , chan nel 0.
OTXD3 — Transmitter output for UART3.
P4[29]/MAT2[1]/
RXD3 B9[1] I/O P4[29] — General purpose digital input/output pin.
OMAT2[1] — Match output for Timer2 , chan nel 1.
IRXD3 — Receiver input for UART3.
P4[30]/CS0 C7[1] I/O P4[30] — General purpose digital input/output pin.
OCS0LOW active Chip Select 0 signal.
P4[31]/CS1 E7[1] I/O P4[31] — General purpose digital input/output pin.
OCS1LOW active Chip Select 1 signal.
ALARM H5[8] OALARM — RTC controlled output. This is a 1.8 V pin. It goes HIGH when a RTC
alarm is generated.
USB_D2N2I/OUSB_D2 — USB port 2 bidirectional D line.
DBGEN E5[1] IDBGEN — JTAG interface control signal. Also used for boundary scan.
TDO B1[1] OTDO — Test Data Out for JTAG interface.
TDI C3[1] ITDI — Test Data In for JTAG interface.
TMS C2[1] ITMS — Test Mode Select for JTAG interface.
TRST D4[1] ITRSTTest Reset for JTAG interface.
TCK D2[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 C4[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 H2 O RSTOUTThis is a 3.3 V pin. LOW on this pin indicates UM10237 being in
Reset state.
RESET J1[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 L2[8] I Input to the oscillator circuit and internal clock generator circuits.
XTAL2 K4[8] O Output from the oscillator amplifier.
RTCX1 J2[8] I Input to the RTC oscillator circuit.
RTCX2 J3[8] O Output from the RTC oscillator circuit.
Table 120. Pin de scr iption …continued
Symbol Ball Type Description