So, in our machines we've got a main power board with microcontroller, power supplies, and various i/o which is housed in a decent electronics enclosure, and then various other circuit boards in remote parts of the machine.
One group of those boards uses rs485 communication to work with the main board, while our user interface board (20x4 lcd and 6 buttons) runs through a ribbon cable with separate wires for each pin (power, ground, 6 or so for LCD, 6 more for buttons.)
We'd like to get away from the bulky, fragile ribbon cable and use a 4 wire system (power, ground, 2 data) like i2c or rs485 for the interface, but I'm not sure how best to approach it.
If we could make the right changes to the main board, we'd just replace the ribbon cable connector with something smaller and update the code accordingly... but that board is complex, far beyond our ability to redesign in house, and we're several years away from being ready to pay contractors for the next big revision. We can probably handle modifying the interface board design, just not the main control board.
As an interim fix, I was thinking of using something like the expander chip on this board on the interface side to turn i2c (better still if I could find rs485 equivalent) into the relevant i/o. What I can't figure out is a way to adapt 16 pins at the main board. It looks like these i/o expander chips always expect to communicate with a microcontroller. I'd like a pair of chips that convert 16 pins into 4 wires on one end and back from 4 wires to 16 pins again on the other end. In a perfect world, it would use rs485 so that when we do finally redesign the main board we can stick with rs485 for all communication without redesigning the interface board yet again. I can't find anything like what I'm looking for, but I was hoping maybe I'm just using the wrong search terms or something.
Anyone know if such a thing exists, or if there's a better way to achieve a similar effect? Or is this just really a bad idea, and we should continue dealing with ribbon cable until we can redesign all electronics at once?
Thanks in advance for your help.
One group of those boards uses rs485 communication to work with the main board, while our user interface board (20x4 lcd and 6 buttons) runs through a ribbon cable with separate wires for each pin (power, ground, 6 or so for LCD, 6 more for buttons.)
We'd like to get away from the bulky, fragile ribbon cable and use a 4 wire system (power, ground, 2 data) like i2c or rs485 for the interface, but I'm not sure how best to approach it.
If we could make the right changes to the main board, we'd just replace the ribbon cable connector with something smaller and update the code accordingly... but that board is complex, far beyond our ability to redesign in house, and we're several years away from being ready to pay contractors for the next big revision. We can probably handle modifying the interface board design, just not the main control board.
As an interim fix, I was thinking of using something like the expander chip on this board on the interface side to turn i2c (better still if I could find rs485 equivalent) into the relevant i/o. What I can't figure out is a way to adapt 16 pins at the main board. It looks like these i/o expander chips always expect to communicate with a microcontroller. I'd like a pair of chips that convert 16 pins into 4 wires on one end and back from 4 wires to 16 pins again on the other end. In a perfect world, it would use rs485 so that when we do finally redesign the main board we can stick with rs485 for all communication without redesigning the interface board yet again. I can't find anything like what I'm looking for, but I was hoping maybe I'm just using the wrong search terms or something.
Anyone know if such a thing exists, or if there's a better way to achieve a similar effect? Or is this just really a bad idea, and we should continue dealing with ribbon cable until we can redesign all electronics at once?
Thanks in advance for your help.