UM10237_2 © NXP B.V. 2008. All rights reserved.
User manual Rev. 02 — 19 December 2008 152 o f 792
NXP Semiconductors UM10237
Chapter 8: LPC24XX Pin configuration
P4[21]/A21/
SCL2/SSEL1 115[1] M15[1] I/O P4[21] — General purpose digital input/output pin.
I/O A21 — External memory address line 21.
I/O SCL2 — I2C2 clock input/output (this is not an open-drain pin).
I/O SSEL1 — Slave Select for SSP1.
P4[22]/A22/
TXD2/MISO1 123[1] K14[1] I/O P4[22] — General purpose digital input/output pin.
I/O A22 — External memory address line 22.
OTXD2 — Transmitter output for UART2.
I/O MISO1 — Master In Slave Out for SSP1.
P4[23]/A23/
RXD2/MOSI1 129[1] J15[1] I/O P4[23] — General purpose digital input/output pin.
I/O A23 — External memory address line 23.
IRXD2 — Receiver input for UART2.
I/O MOSI1 — Master Out Slave In for SSP1.
P4[24]/OE 183[1] B8[1] I/O P4[24] — General purpose digital input/output pin.
OOELOW active Output Enable signal.
P4[25]/WE 179[1] B9[1] I/O P4[25] — General purpose digital input/output pin.
OWELOW active Write Enable signal.
P4[26]/BLS0 119[1] L15[1] I/O P4[26] — General purpose digital input/output pin.
OBLS0 — LOW active Byte Lane select signal 0.
P4[27]/BLS1 139[1] G15[1] I/O P4[27] — General purpose digital input/output pin.
OBLS1 — LOW active Byte Lane select signal 1.
P4[28]/BLS2/
MAT2[0]/TXD3 170[1] C11[1] I/O P4 [28] — General purpose digital input/output pin.
OBLS2 — LOW active Byte Lane select signal 2.
OMAT2[0] — Match output for Timer2, channel 0.
OTXD3 — Transmitter output for UART3.
P4[29]/BLS3/
MAT2[1]/RXD3 176[1] B10[1] I/O P4[29] — General purpose digital input/output pin.
OBLS3 — LOW active Byte Lane select signal 3.
OMAT2[1] — Match output for Timer2, channel 1.
IRXD3 — Receiver input for UART3.
P4[30]/CS0 187[1] B7[1] I/O P4[30] — General purpose digital input/output pin.
OCS0LOW active Chip Select 0 signal.
P4[31]/CS1 193[1] A4[1] I/O P4[31] — General purpose digital input/output pin.
OCS1LOW active Chip Select 1 signal.
ALARM 37[8] N1[8] OALARM — RTC controlled output. This is a 1.8 V pin. It goes HIGH when
a RTC alarm is generated.
USB_D252U1I/OUSB_D2 — USB port 2 bidirectional D line.
DBGEN 9[1] F4[1] IDBGEN — JTAG interface control signal. Also used for boundary
scanning.
TDO 2[1] D3[1] OTDO — Test data out for JTAG interface.
TDI 4[1] C2[1] ITDI — Test data in for JTAG interface.
TMS 6[1] E3[1] ITMS — Test Mode Select for JTAG interface.
TRST 8[1] D1[1] ITRSTTest Reset for JTAG interface.
Table 122. LP C242 0/60/68 pin description …continued
Symbol Pin Ball Type Description