Expander chip difficulties.
KenBash
Posts: 68
I have a Propeller board controling a test system.· I am communicating with two MCP23016 I/O expanders hooked into the same serial·clock and data lines.· One expander chip is located on a secondary board and linked with a ribbon cable.· I have had this system·go into a·mode that "Resembles" a problem with a single processor on the propeller, but is most likely something to do with the I2Cobject communication function.·
IN normal operation,··The·Propeller is getting data from both I/O expander chips,·checking some logic and updating a display screen with the 1's and 0's showing the logic state of both IO expanders.· The screen update normally happens about 3- 5 times a second.· The "Failure" that·I am seeing, has the screen updating at about 1 screen per·50 seconds· and returns all·zeros for all IO logic.···It is possible that I have an intermittent connection ( but can't·find it)· from my main board to this daughter board.
When the cable is simply "Pulled" the system knows that it has lost communication and resets my system.·· In this particular failure mode, it is simply responding very, very ·slowly and··latching outputs on.·
My question is:· Is it possible that this behavior results from a intermittent serial data·or clock signal on the expander chip?· or less probable... that one of my processors on the propeller is going into a SLOW mode of operation... leaving the others functioning correctly ( TV display... etc )
Thanks for any help or suggestions.
Ken Bash
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" Anything worth doing... is worth overdoing. "
··············································· ( R.A.H. )
····································
IN normal operation,··The·Propeller is getting data from both I/O expander chips,·checking some logic and updating a display screen with the 1's and 0's showing the logic state of both IO expanders.· The screen update normally happens about 3- 5 times a second.· The "Failure" that·I am seeing, has the screen updating at about 1 screen per·50 seconds· and returns all·zeros for all IO logic.···It is possible that I have an intermittent connection ( but can't·find it)· from my main board to this daughter board.
When the cable is simply "Pulled" the system knows that it has lost communication and resets my system.·· In this particular failure mode, it is simply responding very, very ·slowly and··latching outputs on.·
My question is:· Is it possible that this behavior results from a intermittent serial data·or clock signal on the expander chip?· or less probable... that one of my processors on the propeller is going into a SLOW mode of operation... leaving the others functioning correctly ( TV display... etc )
Thanks for any help or suggestions.
Ken Bash
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
" Anything worth doing... is worth overdoing. "
··············································· ( R.A.H. )
····································
Comments
Make sure the two MCP23016 have different I/O select addresses
It's hard to tell what's going on without more information. At a minimum, you should provide a schematic, at least of the part of the system we're talking about, and a copy of the source program, both as attachments.