> 3.10.1 | GPIOs

> The TC65 Terminal provides 10 GPIO pins at the IO interface connector. Each GPIO line is ESD protected and a serial resistor of 100 Ohm is added. This avoids short circuits and is especially important in the first stages of development where the Java application is not yet fully implemented.
> The signal direction (input/output) of the GPIO lines is selectable with AT commands. Figure 11 shows the position of the GPIO pins at the IO interface connector.
> Alternatively GPIO pin10 can be used to configure, to start or stop a pulse counter for an input range of 0 to 1000 pulses per second. If the pulse counter is active the pin10 is not available for GPIO signals.
> The GPIOs and the pulse counter can be configured via the following AT commands: AT^SPIO, AT^SCPIN, AT^SCPOL, AT^SCPORT, AT^SDPORT, AT^SGIO, AT^SSIO, AT^SCCNT, AT^SSCNT. For details please refer to [1].
> Figure 13: Location of GPIO pins
> When the TC65 Terminal starts up, all GPIO pins are set to high-impedance state after initializing, as described in Section 3.5.5. Therefore, it is recommended to connect pull-up or pull-down resistors to all GPIO pins you want to use as output. This is necessary to keep these pins from floating or driving any external devices before all settings are done by AT command (at least AT^SPIO, AT^SCPIN), and after closing the GPIOs again.