Using Digital I/O lines...

[Racer26]

A thought that just occurred to me.

In the past 1075 has come very close to using all 8 of our relay outputs on the RC.

From my understanding of how they work, is they're basically a GND line with two signal lines, 1 for forward, and 1 for reverse.

This leads me to a 2part question:

1) Could you not then, in theory, configure some of your Digital I/Os as Output, and emulate the Relay ports by switching two signal lines appropriately?

2) Would this be FRC legal?

[Eugene Fang]

I don't know about your question, but you could save some relay outs if you're using pneumatics by hooking up two solenoids to one spike.

[Racer26]

Potentially, yes, you could share a spike. Depending on the utilization and types of solenoids being used.

[Guy Davidson]

I'm not sure about whether or not you could do it, but, I don't think it would be FRC legal. On some level, it oculd be considered a custom circuit, and as per R03, that might be illegal. Actually, I think it's outright illegal by R62:

Originally Posted by <R62>

All electrical loads (motors, actuators, compressors) must be controlled by relay or PWM output signals sent by the Robot Controller...

I guess it depends on how you read that rule. I don't see anything else in the manual that would prohibit it though.

[Racer26]

Looks to me like <R62> DOES indeed prohibit it. I can't see why it wouldn't be electrically possible to do though.

EDIT: I suspect <R62> prohibits it because the USER processor directly controls the Dig I/O lines I think, whereas the Relay/PWM ports are controlled by the Master processor, which locks them out when disabled.

[The Lucas]

1) It will work

2) It is illegal per <R62>

I inspected a team that was using digital outs instead of relay outputs. It was a misunderstanding on how to use EasyC. The system worked, even stopped the compressor at the right time (they wrote code for that). They changed the wiring and the code to use the OItoRelay function.

[Kevin Sevcik]

Originally Posted by 1075guy

Looks to me like <R62> DOES indeed prohibit it. I can't see why it wouldn't be electrically possible to do though.

EDIT: I suspect <R62> prohibits it because the USER processor directly controls the Dig I/O lines I think, whereas the Relay/PWM ports are controlled by the Master processor, which locks them out when disabled.

The relay lines are controlled by the User processor as well, much like PWMs 13-16. The PWMs and Relay lines are just sent through buffers that are enabled/disabled by the master processor. So yes, the reason it's illegal is because the relays couldn't be disabled directly by the master processor anymore.