Problem with 2 MOSI SPI for the PmodDA1

[vola]

Hello, I want to use the PmodDA1 device with one thread SPI for the 4 DA converters.

Unfortunately, the module has 1 chip select line and 2 Data lines.

Why don't you do the contrary : 2 chip select lines and 1 data line ?

I will have to cut the wires to do this and use your device, it's strange, no ?!!

Sincerely yours,

Jean-Pierre

[JColvin]

Hi Jean-Pierre,

I believe the PmodDA1 was designed so that users would be able to send out two separate digital signals simultaneously in case they wanted to be able produce two different voltages or have separate waveforms that they could measure the frequency difference of (presuming their circuit was set up for that). I think I understand what you're hoping for, although the schematic changes you made show some of the data lines connected to the SYNC lines which wouldn't work out too well.

Perhaps the picture below is what you were thinking of?

Otherwise, if you are looking to have multiple D/A outputs from a single SPI port, I would recommend checking out the PmodDA4; it can output 8 D/A channels simultaneously from a single SPI line.

Let me know if you have any more questions.

Thanks,
JColvin 

[vola]

Hello I think I'm not clear.

So I send you my idea for changing the wire for the D0, D1 and SYNC signals.

Best regards,

 

Jean-Pierre

PmodDA1 sch modified.pdf

[vola]

Hi, JColvin,

Thank you for your answer. You are right for the schematic you modifiy, it is what I want to do. In my project I need 4 digital outputs (not 8, but why not,...) that I program with LabVIEW 2013 throught one ARDUINO UNO. The 4 analog channels are quite static and need, from time to time, some minor "manual" adjustments. Your answer show me that my solution is possible even if the object is different from what Digilent want to do first with the PmodDA1.

Thanks a lot and best regards,

Jean-Pierre