Samsung S3C9454B User Manual page 141

I/O PORTS
9-8
MSB .7 .6
[.7] Port 1.1 N-Channel Open-Drain Enable Bit
0 = Configure P1.1 as a push-pull output
1 = Configure P1.1 as a n-channel open-drain output
[.6] Port 1.0 N-Channel Open-Drain Enable Bit
0 = Configure P1.0 as a push-pull output
1 = Configure P1.0 as a N-channel open-drain output
[.5-.4] Not used for S3C9454B/F9454B
[.3-.2] Port 1, P1.1 Configuration Bits
0 0 = Schmitt trigger input;
0 1 = Schmitt trigger input; pull-up enable
1 0 = Push-pull output
1 1 = Schmitt trigger input; pull-down enable
[.1-.0] Port 1, P1.0 Configuration Bits
0 0 = Schmitt trigger input;
0 1 = Schmitt trigger input; pull-up enable
1 0 = Push-pull output
1 1 = Schmitt trigger input; pull-down enable
NOTE: When you use external oscillator, P1.0, P1.1 must be set to
output port to prevent current consumption.
Figure 9-7. Port 1 Control Register (P1CON)
Port 1 Control Register
E9H, R/W
.5 .4 .3 .2 .1 .0 LSB
S3C9454B/F9454B