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S3C84E5/C84E9/P84E9 I/O PORTS
9-3
PORT 0
Port 0 is an 8-bit I/O port that you can use two ways:
— General-purpose digital I/O
— Alternative function: TACAP, TACK, T1CAP0, T1OUT1, T1CK1, T1CAP1, XTIN, XTOUT
Port 0 is accessed directly by writing or reading the port 0 data register, P0 at location E0H in set 1, bank 0.
Port 0 Control Register (P0CONH/P0CONL)
Port 0 has two 8-bit control registers: P0CONH for P0.4–P0.7 and P0CONL for P0.0–P0.3. A reset clears the
P0CONH and P0CONL registers to “00H” and “0FH”, configuring all pins to input modes. You use control registers
settings to select input or output mode (push-pull) and enable the alternative functions.
When programming the port, please remember that any alternative peripheral I/O function you configure using the
port 0 control registers must also be enabled in the associated peripheral module.
Port 0 Control Register, High Byte (P0CONH)
E6H, Set1, Bank0, R/W, Reset value="00"
.7 .6 .5 .4 .3 .2 .1 .0MSB LSB
[.7-.6] P0.7/TACAP Configuration Bits
0 0 = Input mode with pull-up; TACAP input
0 1 = Input mode; TACAP input
1 X = Push-pull output mode
[.5-.4] P0.6/TACK Configuration Bits
0 0 = Input mode with pull-up; TACK input
0 1 = Input mode; TACK input
1 X = Push-pull output mode
[.3-.2] P0.5/T1CAP0 Configuration Bits
0 0 = Input mode with pull-up; T1CAP0 input
0 1 = Input mode; T1CAP0 input
1 X = Push-pull output mode
[.1-.0] P0.4/T1OUT1 Configuration Bits
0 0 = Input mode with pull-up
0 1 = Input mode
1 0 = Push-pull output mode
1 1 = Alternative function mode: T1OUT1 output
Figure 9-1. Port 0 High Byte Control Register (P0CONH)