3.21_worlds firmware evaluation

[jpearman]

I did some testing of the new 3.21 worlds firmware today, the results are mixed.

Update 1.
The following was observed the first time I ran these tests, I subsequently tested again with standard 3.21 firmware but was unable (so far) to duplicate the results. In other words, the standard firmware was able to establish a link every time I power cycle the cortex. No idea what to make of this, perhaps something to do with WiFi channel selection or interference, anyway, this is what what I fould the first time around.

Update 2.
Looking more closely at the failed link condition, it does appear that the user code does try and start as the LED in the digital port turns on, however, something then goes wrong.

Original Test.
The test condition used a cortex (hardware rev A3) running a small EasyC program tested first with the new 3.21_worlds firmware and then with the standard 3.21 firmware that is included with the current releases of EasyC (4.1.0.1) and ROBOTC (3.08). A joystick using 3.21 firmware was linked to the cortex with a competition switch connected set to driver control, power from the cortex was then removed and reapplied, the time taken to link back to the joystick was measured. This was supposed to simulate a reset to the cortex (for example, motors stall causing brown out or battery connector was loose). For the purpose of this test there was no backup battery.

The standard firmware links approximately twice as fast as the new firmware, however, 50% of the time it failed to re-establish a link giving a single green VEXnet LED.

The worlds firmware always managed to re-establish a link but this takes on average 19 seconds after reapplication of power.

A video showing a comparison between standard and worlds firmware when a link is successfully achieved is posted here. (click on image to play)



A video showing a comparison between standard and worlds firmware when the standard firmware fails to achieve a link is posted here. (click on image to play)



So my conclusion is that the new worlds firmware (in my environment) is slower to re-establish a VEXnet link after a power loss but is more reliable when compared to the standard firmware.

[devinc]

Thank you for this test. My team has not yet installed the new firmware. I like how it re-connects better because we always seem to have problems with our connections dropping.

[diegohuyke]

Thanks for the imperical evaluation.

Although my team hasn't tested the new firmware yet, we will be eager to post our results if anything significant (or different) is noted.

[FirePhoenix]

Thanks for the test. Um what firmware does robotC 3.04 run with? Can you compare that with 3.21 worlds if robotC 3.04 didn't use 3.21?

[jpearman]

Originally Posted by FirePhoenix

Thanks for the test. Um what firmware does robotC 3.04 run with? Can you compare that with 3.21 worlds if robotC 3.04 didn't use 3.21?

ROBOTC 3.04 uses master and joystick firmware 3.16. I have used this for many months and it seems stable, I don't know if it suffers the problems of 3.21 but the teams I coach used it at several competitions without problems.

[FirePhoenix]

Originally Posted by jpearman

ROBOTC 3.04 uses master and joystick firmware 3.16. I have used this for many months and it seems stable, I don't know if it suffers the problems of 3.21 but the teams I coach used it at several competitions without problems.

Can you compare it with the worlds. I really don't want to update the firmware. It's so reliable

[jumper11]

We have been using firmware v3.16 and it has been working fine so we probably won't change to the Worlds firmware unless there is another reason to.

[jpearman]

Originally Posted by FirePhoenix

Can you compare it with the worlds. I really don't want to update the firmware. It's so reliable

I will test 3.16 at some point, I have been trying (with success) to duplicate the fail condition of the standard 3.21 firmware and then got distracted into sniffing the WiFi.

My (unofficial) advice is that "if it isn't broken, don't fix it"

[devinc]

Originally Posted by jpearman

I will test 3.16 at some point, I have been trying (with success) to duplicate the fail condition of the standard 3.21 firmware and then got distracted into sniffing the WiFi.

My (unofficial) advice is that "if it isn't broken, don't fix it"

that is what I always say

[jgraber]

Reaction: Fix things when they break.
- But your robot is already broken by then.
- Just because your robot works fine before you put it in the box to ship to worlds, doesn't mean it will be fine after shipping, at the worlds venue, with 3000 other wifi running.

Conservative: If it ain't broke, don't fix it.

Denial: If it ain't broke now, it ain't never gonna break in the future.

Tinkering: If it ain't broke, break it! Then fix it better than new.

Proaction: Look for things that are about to break, by seeing reports of other peoples problems, and look for ways to make your robot more robust.
- Test multiple software versions to find out if they work for you.
Do it in advance, so you don't have to panic at the last minute.
- Have "quick-swap" cortex physical and electrical connections, and a spare, pre-programmed cortex ready to swap in during your time out.

A joystick using 3.21 firmware was linked to the cortex with a competition switch connected set to driver control, power from the cortex was then removed and reapplied, the time taken to link back to the joystick was measured. This was supposed to simulate a reset to the cortex (for example, motors stall causing brown out or battery connector was loose). For the purpose of this test there was no backup battery.

I heard advice once: "If you think the field is causing you to be disabled during driver control, just pull the competition plug; Now if it doesn't work, you know it is your own robot fault" Was that only from the pre Vexnet days of Crystals, or does it still apply to vexnet ? Does pulling the competition cable out of the Vexnet joystick cause a wifi-disconnect?