Laptop User Manual
S3C2440A RISC MICROPROCESSOR     PRODUCT OVERVIEW 
  1-23 
Table 1-3. S3C2440A Signal Descriptions (Sheet 3 of 6) 
Signal Input/Output   Descriptions 
UART 
RxD[2:0]  I  UART receives data input 
TxD[2:0]  O  UART transmits data output 
nCTS[1:0]  I  UART clear to send input signal 
nRTS[1:0]  O  UART request to send output signal 
UEXTCLK  I  External clock input for UART 
ADC 
AIN[7:0]  AI  ADC input[7:0]. If it isn’t used pin, it has to be Low (Ground). 
Vref AI ADC Vref 
IIC-Bus 
IICSDA IO IIC-bus data 
IICSCL IO IIC-bus clock 
IIS-Bus 
I2SLRCK  IO  IIS-bus channel select clock 
I2SSDO  O  IIS-bus serial data output 
I2SSDI  I  IIS-bus serial data input 
I2SSCLK  IO  IIS-bus serial clock 
CDCLK  O  CODEC system clock 
AC’97 
AC_SYNC 
O  48 kHz fixed rate sample sync 
AC_BIT_CLK 
IO  12.288 MHz serial data clock 
AC_nRESET 
O  AC’97 Master H/W Reset 
AC_SDATA_IN 
I  Serial, time division multiplexed, AC’97 input stream 
AC_SDATA_OUT 
O  Serial, time division multiplexed, AC’97 output stream 
Touch Screen 
nXPON  O  Plus X-axis on-off control signal 
XMON  O  Minus X-axis on-off control signal 
nYPON  O  Plus Y-axis on-off control signal 
YMON  O  Minus Y-axis on-off control signal 
USB Host 
DN[1:0]  IO  DATA(–) from USB host. (Need to 15K ohm pull-down) 
DP[1:0]  IO  DATA(+) from USB host. (Need to 15K ohm pull-down) 
USB Device 
PDN0  IO  DATA(–) for USB peripheral. 
(Need to 470K ohm pull-down for power consumption in sleep mode) 
PDP0  IO  DATA(+) for USB peripheral. (Need to 1.5K ohm pull-up) 










