pic: 4143 RoboRio expansion card prototypes ordered

[AllenGregoryIV]

I'm still not really clear what exactly is on this board.

I see the additional analog inputs but the rest of the board and your description still needs more explanation for me to fully grasp what you are doing here.

Are you saying there is a connector for an arduino or is there an arduino on this board?

Did you bring out the rest of the PWM outputs as well, I imagine this will be one of the more requested features for all the expansion boards.

[RyanShoff]

It is just a glue board. There are no components other than headers and sockets. You plug this in the rio. You plug an Arduino into this. It breaks out the extra rio analog I/O from the MXP connector and puts an Arduino on the i2c bus.

I know a lot of teams use an Arduino on the i2c bus for fancy light shows. Andymark has a kit for this. The timing of the LED strip protocol is strict enough that it still probably makes sense to offload that to a separate microcontroller.

[RyanShoff]

I'll probably break out some PWM to headers on the next version. Though I'm not sure CAN Talons wouldn't be a better option.

[magnets]

Originally Posted by RyanShoff

The timing of the LED strip protocol is strict enough that it still probably makes sense to offload that to a separate microcontroller.

I'd consider it pretty awful if our severely discounted, dual core 667MHz, ARM, $430 controller with an FPGA can't keep up with a $5 microcontroller, and had timing issues like these.

[Andrew Schreiber]

Originally Posted by magnets

I'd consider it pretty awful if our severely discounted, dual core 667MHz, ARM, $430 controller with an FPGA can't keep up with a $5 microcontroller, and had timing issues like these.

It probably CAN keep the timing requirements. But why add on that requirement and slow down everything else when you can offload the processing to a $5 processor. Add on to that, we can use it to teach MORE students DIFFERENT programming skills.

[Joe Ross]

Originally Posted by magnets

I'd consider it pretty awful if our severely discounted, dual core 667MHz, ARM, $430 controller with an FPGA can't keep up with a $5 microcontroller, and had timing issues like these.

The same program written on an i7 with Java and windows probably couldn't keep up either. The same program written to take advantage of real-time features of the cRIO on vxworks probably could keep up.

[RyanShoff]

Boards came in. They'll need some tweaking, but they look pretty cool.

[RyanShoff]

I made some changes and pushed everything to github.
https://github.com/FRC-Team-4143/4143shield

It is probably now functional but untested. It appears to fit good over printed full scale prints from the NI website. There may be some interference between Arduinos with full size USB ports and the solder joints for the RoboRio connector. I'll make another revision if that is the case. I broke out 4 PWM lines also this time.

[RyanShoff]

Pics of the prototype. I guess this project will get shelved for a while. There aren't any beta teams very close.

http://s3.amazonaws.com/rshoff/4143/...702_102846.jpg
http://s3.amazonaws.com/rshoff/4143/...702_102857.jpg

[connor.worley]

Originally Posted by magnets

I'd consider it pretty awful if our severely discounted, dual core 667MHz, ARM, $430 controller with an FPGA can't keep up with a $5 microcontroller, and had timing issues like these.

The controller could nail the timing - RT Linux can't

[fovea1959]

where did you order them from? we're a beta team, and would like to take one out for spin early; the earlier we wring out the wrinkles, the better....

[RyanShoff]

Originally Posted by fovea1959

where did you order them from? we're a beta team, and would like to take one out for spin early; the earlier we wring out the wrinkles, the better....

I ordered a small batch of boards from a chinese board shop. The first boards have a design flaw that make them unusable. But they are perfect for fit up testing. I haven't made the corrected version yet, because I haven't been around beta hardware yet.

I'll gladly send you a board to plug in, if you can post pictures of it installed here.

Once fit and clearances are verified, I'll get another small batch made of the corrected version.

PM me an address and I'll get one sent off.

[RyanShoff]

Bombsquad let me test the MXP board for fitup last weekend at GRC. Thanks.

Looks good, but now I'm not sure we'll be allowed to use the MXP port next year. Apparently there is debate about the safety of the port. Not sure I get that. Copper on a board is the same as copper in a wire to me.

I guess we could add analog inputs through the i2c or spi busses.