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UM10237_2
© NXP B.V. 2008. All rights reserved.
User manual
Rev. 02 — 19 December 2008
152 of 792
NXP Semiconductors
UM10237
Chapter 8: LPC24XX Pin configuration
P4[21]/A21/
SCL2/SSEL1
115
M15
I/O
P4[21] —
General purpose digital input/output pin.
I/O
A21 —
External memory address line 21.
I/O
SCL2 —
I
2
C2 clock input/output (this is not an open-drain pin).
I/O
SSEL1 —
Slave Select for SSP1.
P4[22]/A22/
TXD2/MISO1
123
I/O
P4[22] —
General purpose digital input/output pin.
I/O
A22 —
External memory address line 22.
O
TXD2 —
Transmitter output for UART2.
I/O
MISO1 —
Master In Slave Out for SSP1.
P4[23]/A23/
RXD2/MOSI1
129
I/O
P4[23] —
General purpose digital input/output pin.
I/O
A23 —
External memory address line 23.
I
RXD2 —
Receiver input for UART2.
I/O
MOSI1 —
Master Out Slave In for SSP1.
P4[24]/OE
183
B8
I/O
P4[24] —
General purpose digital input/output pin.
O
OE —
LOW active Output Enable signal.
P4[25]/WE
179
B9
I/O
P4[25] —
General purpose digital input/output pin.
O
WE —
LOW active Write Enable signal.
P4[26]/BLS0
119
L15
I/O
P4[26] —
General purpose digital input/output pin.
O
BLS0 —
LOW active Byte Lane select signal 0.
P4[27]/BLS1
139
G15
I/O
P4[27] —
General purpose digital input/output pin.
O
BLS1 —
LOW active Byte Lane select signal 1.
P4[28]/BLS2/
MAT2[0]/TXD3
170
C11
I/O
P4 [28] —
General purpose digital input/output pin.
O
BLS2 —
LOW active Byte Lane select signal 2.
O
MAT2[0] —
Match output for Timer 2, channel 0.
O
TXD3 —
Transmitter output for UART3.
P4[29]/BLS3/
MAT2[1]/RXD3
176
I/O
P4[29] —
General purpose digital input/output pin.
O
BLS3 —
LOW active Byte Lane select signal 3.
O
MAT2[1] —
Match output for Timer 2, channel 1.
I
RXD3 —
Receiver input for UART3.
P4[30]/CS0
187
B7
I/O
P4[30] —
General purpose digital input/output pin.
O
CS0 —
LOW active Chip Select 0 signal.
P4[31]/CS1
193
A4
I/O
P4[31] —
General purpose digital input/output pin.
O
CS1 —
LOW active Chip Select 1 signal.
ALARM
37
N1
O
ALARM —
RTC controlled output. This is a 1.8 V pin. It goes HIGH when
a RTC alarm is generated.
USB_D
−
2
52
U1
I/O
USB_D
−
2 —
USB port 2 bidirectional D
−
line.
DBGEN
9
I
DBGEN —
JTAG interface control signal. Also used for boundary
scanning.
TDO
2
D3
O
TDO —
Test data out for JTAG interface.
TDI
4
C2
I
TDI —
Test data in for JTAG interface.
TMS
6
E3
I
TMS —
Test Mode Select for JTAG interface.
TRST
8
D1
I
TRST —
Test Reset for JTAG interface.
Table 122. LPC2420/60/68 pin description
…continued
Symbol
Pin
Ball
Type
Description