No bothering. I would suggest you to do something with an output enable signal which will pit your cap loading into Hi-Z when sensing. OE is a property of the pin and you can feed it using your PWM signals.
I tried with something similar, but if i change the pin configuration to Hi-Z the cap don't discharges... basically I need to read this "time of discharge" but i can only discharge it if its in "open drain" configuration. Maybe i'm messed up... any form to read this cap discharge and pulse it? have tried bidirectional pins... enabling digital input and digital output of one pin.. but not success.
Still going on with this problem... have to do this.
The procedure for using them is:
1. Make the I/O an ouput
2. Allow at least 10 us for the 10 nF capacitor to charge
3. Make the I/O an input
4. Measure the time for the capacitor to discharge by waiting for the I/O line to go low
I'm usign PSoC 5LP Kit CY8CKIT-059. I'll try to change the gpio on firmware like..
1. Strong drive output <- PWM 10us ton
2. High Z Dig <- Timer
I think it's the way to do it... but not sure.