Gah!

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Attempting a second email post…

Lunch today consisted of some sort of weird chicken schnitzel sandwich thing at Gustav’s, which is a little pricey, but the sandwich was really good. I have had mixed drinks cheaper than what they charge for the lemonade, though. Gustav’s is not the place to take a vegetarian.

When you have two pieces of prototype hardware on the network and you are trying to figure out why one never works and why the other intermittently works, check the hardware MAC address. Our devices have the networking logic in their CPUs, direct from Atmel, and we never thought to look or change the MAC, so all of the prototypes are 00:23:31:37:00:00. It turns out that we have one good prototype and one bad prototype, but sometimes I see the good one as the bad and vice-versa because they both want to respond, regardless of which one I think I am talking to.

Seriously, I have been ripping my hair out since Friday because the good prototype passes every test, has no discernible faults when I am physically testing it, but [appears to] blow chunks when I am using it over the network. Everything is fine; I have just been mistakenly talking to the broken prototype over the network. Gaaaahhhhh!!!!

In other crazy hardware news, gigabit ethernet actually does seem to work when you run it through about 30cm of wire-wrap wire instead of the normal cat5/cat6.

Don’t renumber your parts when you revise a circuit board (or at least tell people that you renumbered). The assembly people know that, for instance, R74 is 100 ohm. When you renumber, R74 is no longer R74 and could be a completely different value resistor, meaning the people who program the pick-and-place machine get confused and hand you hardware that is broken before power is even applied to it.

Stupid MAC addresses.

-Brian

Posted in: Work

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