Triggering an SX-28 with another SX-28 ??

T&E Engineer

If I have 2 SX-28 chips and want to have 1 of them trigger the other one, how can this be done?

I have a program running in 1 SX-28 and I want to sync another SX-28 with it so that they run there programs simultaneously.

I want to duplicate the same program on both but have them sync'd together.

The SX-28 only allows for arrays up to 16 bytes and I need to have more so I can always use 2 (or more) separate SX-28 chips. However, I think I would need them to be sync'd together to make sure that one is a master and the other is a slave.

Has anyone done this yet?

JonnyMac

It think that's going to be a bit tricky, but if I were inclined to try I would look for two edges: the first says "get ready," the next says "go!"

I have created arrays of up to 64 bytes using SX/B on the SX28; it just takes a little bit of management code to do it. There's a couple of posts in the forums that show how (like the HP printhead driver project).

T&E Engineer

Thanks JonnyMac.

That's right. Jon Williams worked that out for me sometime back with the 64 byte array.

This is what I am trying to do:

One of my other recent posts show Jon's modified code using an SX-28 and RB and RC to display a message on an 8x8 LED display (in my case a 7x5). However, due to the output limitations and simplicity of the code writing, I would like to cascade this onto another SX-28. so that the message is longer than 8x8 / 7x5. Perhaps it could be 8x16 / 7x10 by adding·another LED module and an SX-28. However, I would think that the SX-28 would have to be sync'd to a master SX-28 to allow for the clean transition of the message scrolling (e.g. 1 array that is 8 bytes wide on the 1st SX-28 into an array on 2nd SX-28 that is 8 bytes wide, etc.). Both SX-28 chips would use RB and RC on each one.

Ideas. Comments?

JonnyMac

JonnyMac --> nick-name for Jon McPhalen --> professional name for the actor also known as Jon Williams, former Parallax employee. The Screen Actors Guild reminded me that there's already a famous Jo[noparse][[/noparse]h]n Williams (the Star Wars composer guy) and that I needed to pic a new name for my acting work. The only people who know me as Jon Williams anymore are those in the electronics world; most of my personal friends are in show business and only know me only as Jon McPhalen.

Since the display can only enable one column at a time why not add a (cheaper) 74x138 multiplexer for column control ? You could get really crafty and use two (or use the 74x154 - like on the Robolympics badge) to get 16 columns. You might even get really tricky and do an interleave of the columns.

Post Edited (JonnyMac) : 3/6/2007 9:16:18 PM GMT