Maxim 4-wire SPI interface

[GuessWho]

Hi Folks we are looking for a way to drive some Maxim 6954 LED drivers with an SPI interface from a PC, I would expect via USB.  Is anyone aware of a robust, simple 2-way communication device for USB-SPI, preferrably with a LabVIEW interface?  Thanks

[TroyK]

Did you try a search in the hardware section of ni.com?

Products > Hardware > Industrial Communication Buses > I2C/SPI

NI USB-8451

[GuessWho]

UNRESTRICTED | ILLIMITÉ

Thanks. NI’s website is funky for me today; type USB in the search tool on the home page, and as soon as you hit the space bar after the B in USB, the page hangs. Never returns. So I thought I’d ask.

I see it’s 8 years old and still supported. Guess not much has changed in 8 years in SPI, so that’s okay.

Anyone have any significant gotchas with this product? We’re not bit-banging newbies, but sometimes the devil’s in the details.

Blair

[TroyK]

To be honest I've never used this product.

SPI is faily simple and pretty robust. Last time I had to do it was reading 11 temperature/humidity sensors and the engineer couldn't wait for delivery of one of these. I had a USB6259 lying around so I bit-bashed the clock and data out a digital port and synchronously read the data back on another. Been working really reliably for about a year now.

The USB-8451 has up to 12MHz clock for SPI, the USB-8452 can go to 50MHz, your target seems to be able to handle 26Mbit so speed might be a consideration.

[GuessWho]

UNRESTRICTED | ILLIMITÉ

Hi

I’ve got a need for up to 64 red/green common cathode LEDs and 24 pushbuttons, probably within an 8”h x 16”w x 4”d panel. There will be two of these, located about 30’ apart. From reading the MAX6954 info, one will do one such panel nicely, but I might have to use an NI USB 8451 at each location due to the distances; USB extenders are available, I may look at that. Ideally, I’d be able to do both the panels from one 8451, but I don’t think SPI will work reliably for a 15’ distance, presuming I put the 8451 half way between the panels.

Anyway, thanks for the info; more digging is required.

Blair

[JChristensen]

I would recommend searching for the LabVIEW code to auto detect MAC address

of the device When the device is unplugged the resource has to be

reassigned. The MAC address selection was not obvious to the end users.

Device works well though.

Jeff Christensen

Sent from my Motorola RAZR MAXX

[GuessWho]

UNRESTRICTED | ILLIMITÉ

Jeff

I think this answer was intended for another thread, “DAQ 9234 keep disconnected from PC”? I’m not concerned about disconnects affecting the 825x product I’ve been discussing, though your answer holds promise for another application I’m currently writing which uses an NI CDaq-9178.

Blair

[JChristensen]

This is the link to the auto detection of USB device Mac address.

https://knowledge.ni.com/KnowledgeArticleDetails?id=kA00Z0000019MP5SAM&l=en-US