Sure Electronics 4" 2x7segment LED - 'SPI-like' interface?

[coreywi]

Hi All,

I'm working through creating an IR wireless digital scoreboard based on the Rpi. I've got everything working (hardware/software) with the exception of the final displays, which are on order. At the moment, I'm using a simple 2x16 LCD for the prototyping, which does the trick.

The display I chose was 2 x 4" 2x7segment LED boards from Sure Electronics, which have 74HC595 shift registers for the LED drivers.

http://store3.sure-electronics.com/de-dp22911

The spec sheet for this beastie mentions a 'SPI-like' interface. That concerns me a little since that implies that it's not 'really' a SPI interface, but partly so. We'll see. In any case, I've been doing research on RPi SPI and it looks promising.

But, I need a little validation on what I've done in preparation for the displays arriving. Mainly: that it's feasible to hook up these display boards and talk to them using RPi's SPI, and that using WiringPI to help with the SPI communication itself.

If anyone has any experience with these displays or can pass along any helpful hints with SPI, that would be very appreciated.

Thanks!

[coreywi]

Burngate said this in another one of my posts:

I'm not sure how like full SPI the interface is, but I would ignore that claim, and just go for bit-banging three ordinary GPIOs. It won't need to be very fast, so even using Python you could drive several 595 shift registers at 10Hz refresh rate and still have time to do other things

I guess I just have to read up on the spec-sheet for the shift registers. Understanding and debugging SPI really well out of the RPi is a good justification for getting a data logger digital oscilloscope, which I've just been looking for an excuse to get.

Thanks!

[DougieLawson]

That's very expensive for just two digits.

My eight digit SPI LED cost £1.79 ($2.64)
http://www.ebay.co.uk/itm/201229874308
and that's running right now on my Zero using Richard Hull's MAX2719 library.
https://github.com/rm-hull/max7219

[coreywi]

True, but these 7-segment digits are 4" tall and a onboard LED driver

That why this sucker pulls 0.16A.