USB-IO Interface Adapter - GPIO-24USB-IO Interface Adapter GPIO-24 allows connecting various hardware devices to you PC. Easy installation and plug-and-play support turns GPIO-24 adapter into ideal solution to add USB interface to your HW. |
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- Digital Input Pins Configuration
Each of 24 USB-IO Adapter GPIO pins can be configured as digital input. To turn pin into digital input mode send GPIO SET CFG command. Digital input mode is configured with GPIO SET IN CFG command.
- Digital Input Pins Synchronous Interface
Synchronous interface is quite simple. If you only want to use synchronous interface you can send GPIO SET IN CFG command to configure digital input mode, setting PHASE, DEBOUNCE and REPEAT parameters to 0. Then turn the pin into digital input mode with GPIO SET CFG command.
GPIO GET VAL command reads values for all 24 GPIO pins. For digital input pins this command returns current input values.
- Digital Input Pins Asynchronous Interface
Much more flexibility is given by the asynchronous interface. You can configure digital input pin to send events to your application when input value changes. You can also configure events to be sent for specific changes (e.g. when input value changes from logical 0 to logical 1 or vice versa).
Events can be sent repeatedly while input value is stable. For example, if you want events to be sent each second when the pin has logical 0 at its input, specify PHASE=GPIO_IN_EV_LEV_0 and REPEAT=10 in GPIO SET IN CFG command.
Debounce algorithm is implemented in USB-IO Interface Adapter to avoid sending of numerous events caused by contact bounce. The new value is only accepted if it is stable for a predefined period of time. The time period is configured with DEBOUNCE parameter.
- Digital Input Pins Electrical Characteristics
USB-IO Adapter digital input pins have either TTL or Schmitt Trigger buffer. Refer to I/O Pinout table to determine the input type for each specific pin.
The digital input pins DC Characteristics are specified in the following table:
Characteristic Min Max Units Condition Digital Input Low Voltage: Pins with TTL buffer VSS 0.8 V JP3 open VSS 0.5 V JP3 close Pins with Schmitt Trigger buffer VSS 1.0 V JP3 open VSS 0.66 V JP3 close Digital Input High Voltage: Pins with TTL buffer 2.0 5.0 V JP3 open 1.65 3.3 V JP3 close Pins with Schmitt Trigger buffer 4 5 V JP3 open 2.65 3.3 V JP3 close Input Leakage Current - ±1 µA VSS≤VPIN≤VDD
Pin at high-impedance