how can I acquire digital signals (UART interface) from a MCU with NI USB-6008?

[saraydin]

I have acauired some analog signals through A/D (3 channels). I have put each digitized data on 3 digital output of a microcontroller. I want to see if it is possible to import these 3 digital outputs to a PC through a USB-6008? Is it like connecting the outputs to the digital input of the USB-6008 and import the 3 channels simultaneously to LabView? Do I need to use some other hardware like USB-8451 and connect the clock of the MCU to USB-8451?

[CWolf · Accepted solution]

Saraydin,

The digital I/O on the USB 6008 is software timed only, so unless your signals are rather slow, it will probably not work for you.  In general, the procedure would be to hook up each signal to one of the digital lines on the card and then set up a digital input task in LabVIEW to read the three channels.  If using a device that has hardware-timed digital I/O, you would then input your clock signal and use that as the sample clock for the task.  Here is a list of USB devices that support hardware-timed DIO.  Also, there is an example that ships with LabVIEW, that shows how to do this.  You can get to it from LabVIEW by going to Help>>Find Examples.  When the Example Finder window opens, browse to Hardware Input and Output>>DAQmx>>Digital Measurements>>Cont Read Dig Chan-Ext Clk.vi. 

The 8451 is specifically for I2C and SPI, and would be great if you are trying to do one of those protocols, but otherwise I would recommend the devices from the list I linked above. 

-Christina