Dallas 1-wire transaction with LK204-25-WB Display

[mcnee003]

I have no problems communicating with 1-wire devices when two or fewer devices are attached via a DS1402D-DR8+. However when I tie in another DS1402-DR8+ iButton holder and send out a "Search for a 1-Wire Device" command(0xFE 0xC8 0x2 or 254 200 2) the display blanks out and appears as if it has just been reset or else the power has been cycled. However what is peculiar is that when I use only one iButton device in each of the DS1402-DR8+'s everything is fine; I'm able to read and/or write to whatever iButton is currently attached. It's just when I attach a third iButton that the display blanks itself out and to have had the power cycled to it. Any Suggestions or Comments?????

[Paradigm]

You've definitely got a strange one here. I'm wondering if you might want to employ a better 1-wire bridge. Our displays were meant to connect to simple 1-wire networks, and as such don't employ the advanced concepts such as slew rate limiting and strong/weak pulls.

You might want to research one of the many 1-wire interface options at:

http://para.maxim-ic.com/cache/en/results/4868.html

They will give you a more robust bus master than we designed. The other option is to use a 1-wire bridge. I found them quite a while ago, but can't seem to figure out where the are now. They were on the Maxim site, so maybe all that is needed is a more thorough look. Essentially what these chips did was bridge two 1-wire networks. You address the bridge, tell it to connect then start communicating with the network on the other side. This way you use our one wire master to drive a single device, which then does the heavy lifting to drive the rest of the network.