Samsung S3C2440A - Manual (Page 253)

S3C2440A RISC MICROPROCESSOR I/O PORTS
9-7
PORT CONTROL DESCRIPTIONS
PORT CONFIGURATION REGISTER (GPACON-GPJCON)
In S3C2440A, most of the pins are multiplexed pins. So, It is determined which function is selected for each pins.
The PnCON(port control register) determines which function is used for each pin.
If PE0 – PE7 is used for the wakeup signal in power down mode, these ports must be configured in interrupt mode.
PORT DATA REGISTER (GPADAT-GPJDAT)
If Ports are configured as output ports, data can be written to the corresponding bit of PnDAT. If Ports are
configured as input ports, the data can be read from the corresponding bit of PnDAT.
PORT PULL-UP REGISTER (GPBUP-GPJUP)
The port pull-up register controls the pull-up resister enable/disable of each port group. When the corresponding
bit is 0, the pull-up resister of the pin is enabled. When 1, the pull-up resister is disabled.
If the port pull-up register is enabled then the pull-up resisters work without pin’s functional setting(input, output,
DATAn, EINTn and etc)
MISCELLANEOUS CONTROL REGISTER
This register controls DATA port pull-up resister in Sleep mode, USB pad, and CLKOUT selection.
EXTERNAL INTERRUPT CONTROL REGISTER
The 24 external interrupts are requested by various signaling methods. The EXTINT register configures the
signaling method among the low level trigger, high level trigger, falling edge trigger, rising edge trigger, and both
edge trigger for the external interrupt request
Because each external interrupt pin has a digital filter, the interrupt controller can recognize the request signal that
is longer than 3 clocks.
EINT[15:0] are used for wakeup sources.