PCIe 6535 and legacy interface

I am using PCIe 6535 to get 12 Bits of digital data and 3 sync signals to my computer @ rate of 9 MHz.

I am using MATLAB 2010a (32 bit).

my code:

digital_in = digitalio ('nidaq','Dev1');

addline(digital_in,0:7,'in',{'Bit1','Bit2','Bit3','Bit4','Bit5','Bit6','Bit7','Bit8'});

addline(digital_in,0:6,1,'in',{'Bit9','Bit10','Bit11','Bit12','VD','HD','DCLK'});

digital_bits = getvalue(digital_in.Line(1:12)); 

digital_bits_decimal = binvec2dec(digital_bits); 

VD = getvalue(digital_in.Line(13)); 

HD = getvalue(digital_in.Line(14)); 

DCLK = getvalue(digital_in.Line(15));

This is what i did so far. Now I want to get these data to my computer @ 9MHz speed. I check MATLAB help but I didn't find anything that specifies speed for legacy interface (PCIe 6535). I want to save 25 seconds of digital data @ 9 MHz rate.

My problem is how to specify speed and timing in the MATLAB using legacy interface because my device (PCIe 6535) only supports legacy interface.

Answer 1

[Rob Graessle]

The GETVALUE function in the legacy interface is asynchronous, so it is designed to read one set of values at a time. To acquire multiple values in a row (without regard for timing), you could call GETVALUE inside of a loop. However, if you want to specify a rate at which values are acquired, you could change the TimerFcn and TimerPeriod properties of the digital IO object. For example, if you set TimerPeriod to 0.1 and include a call to GETVALUE inside the TimerFcn callback, a new sample will be acquired every 0.1 seconds. A good example is available in the documentation - just type edit demodaq_callback at the MATLAB prompt. Note, however, that since this uses software-clocked DIO and not hardware-clocked DIO, the acquisition rate will be limited by the speed of your computer and OS.

[Walter Roberson]

Oooch... that's probably going to be a lot less than 9 MHz.