Samsung S3C2440A - Manual (Page 258)

I/O PORTS S3C2440A RISC MICROPROCESSOR
9-12
GPCDAT Bit Description
GPC[15:0] [15:0] When the port is configured as input port, the corresponding bit is the pin
state. When the port is configured as output port, the pin state is the same as
the corresponding bit. When the port is configured as functional pin, the
undefined value will be read.
GPCUP Bit Description
GPC[15:0] [15:0] 0: the pull up function attached to to the corresponding port pin is enabled.
1: the pull up function is disabled.