Counter 0 Up/Down Signal
You can externally input this signal on the P0.6 pin, but it is not available as an output on the I/O connector. When you enable externally controlled count direction, Counter 0 counts down when this pin is at a logic low and counts up when it is at a logic high. If you are using an external signal to control the count direction, do not use the P0.6 pin for output. If you do not enable externally controlled count direction, the P0.6 pin is free for general use.