What are digital I/O?
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Export allEach digital I/O on a LabJack can be individually configured to one of 3 states: input, output-high, or output-low.
A digital input provides a voltage thresholding operation. If the voltage is higher than some value, the computer will detect the digital input as high/set/1. If the voltage is lower than some value, the computer will detect the digital input as low/clear/0.
A digital output allows you to control a voltage with a computer. If the computer instructs the output to be high, the output will produce a voltage (generally about 5 or 3.3 volts). If the computer instructs the output to be low, it is connected to ground and produces no voltage.
For LabJack-specific info on digital I/O, go to the user's guide or datasheet for the device of interest. Start at the main support page and go to the device of interest. For example, in the Section 2 of the U3, U6, or UE9 User's Guide, there is a Section about digital I/O, and Appendix A of each has electrical specs.
Comments
#1
Hi, I am interested in the U6, and am wondering how quickly the digital I/O can capture digital data? I have a 1 bit digital stream that be as fast as 4MHz. Also, if I have an input data stream with accompanying clock, is it possible to write code that will tell the U6 to capture data on only the positive edge of the clock input?
Thanks!
Fred
#2
The fastest you can do is stream mode which is up to 50 ksamples/second (Section 3.2 of the U6 User's Guide), so not fast enough for a 4 MHz signal.
The behavior you describe of capturing data on a clock edge can be done with an externally triggered stream, but only the UE9 supports that (Section 3.2.1 of the UE9 User's Guide), and still limited to the normal stream mode speeds.
Is your 4 MHz signal some sort of standard serial protocol such as SPI, I2C, or asynronous UART? The U6 does have support for some serial protocols discussed in Sections 4.3.10 to 4.3.12.