Are you aware of any extra details with the ports on the cortex?

I’ve come across a few extra things relating to individual ports on the cortex. One being that the motor ports 1-5 and 6-10 will shut down separately in the event of one of the motors overheating. The other is in the image attached to this post. Are you guys aware of any more of things like this?

The details of what you’ve presented are somewhat inaccurate.

The Cortex ports are split into two groups as you list. And, the ports can shut down in those groupings. However, it isn’t simply an issue of “one of the motors overheating.”

Ports 1-5 could be shut down, for instance, without any motor ever “overheating.” All it requires is that the 4 ports together draw more than the current limit for long enough to trigger the current limiting device to go nonconductive. Think of it like tripping a circuit breaker. After a brief period, the “circuit breaker” will reset. (This isn’t really a circuit breaker, it’s a component called a Positive Temperature Coefficient (PTC) device.) No single port would ever have to be in an over-current or overheating condition. There are two PTC devices; one for ports 1-5 and another for ports 6-10.

The issue you refer to in the screenshot from renegade robotics isn’t exactly right either. You can use ports 4 and 10 at the same time, but only in certain ways. The issue is those ports share an interrupt bit in the interrupt controller. So long as you’re not relying on an interrupt for both ports you can use them for independent purposes.

There was an issue some time ago where a bug in the RobotC software could cause the way you configure port 10 to be overwritten by the way you configure port 4. It’s detailed by @jpearman here:

I don’t know whether that’s ever been fixed, but the workaround to the overwriting issue is described in the thread. There is no way to change the two ports on one interrupt issue.

@kypyro - can you make a recommendation as to how I can improve the wording in the article about ports 4 & 10 to make it more accurate? Always happy to learn and improve my articles.



Your articles are one of the first places I send someone for many subjects. I’ll try to provide some brief comments directly to you that might be helpful on that one particular issue. Though, of course, @jpearman is the usual source of “ground truth” when he has time to comment on something like this. I suspect he’s very busy right now. I’m not sure whether the configuration overwriting problem detailed in the link in my previous post has been fixed, though I would guess that it has, since he (@jpearman) discovered the bug in 2013. But you never know; it would be a low priority thing to fix, particularly since there is a workaround.

Hit me in PM here or a message on the much-dreaded facebook if I don’t get back to you in a useful time.

No, it was never addressed, and I don’t think we ever had a customer report the bug.

Thanks for the info! When I supply input to @biglesliep, I’ll include a description of the workaround for the port 4 overwrite problem.