Re: [Paparazzi-devel] New Autopilot board, lia/lisaM fork

[nisma]

Sure, i never had the intention to remove can, and it´s very helpful, especially with the MCP25020/50 chips.

 

Gesendet: Montag, 13. Mai 2013 um 19:04 Uhr

Von: "Karoly Molnar" <address@hidden>
An: "address@hidden" <address@hidden>
Betreff: Re: [Paparazzi-devel] New Autopilot board, lia/lisaM fork

I second what Piotr has written below. CAN is already common in commercial avionics for good reason. Building up a comparable low level protocol stack in software is pointless and more error prone. Adding RS485 (not replacing) might make sense as a number of high end servos are using RS485 for communication. 

If you mean to use RS485 transceivers and keep CAN protocol, well then you will have a working system that is not 100% compatible to CAN and might not work on higher baud rates.

 

Regards

Karoly

 

> Date: Sun, 12 May 2013 12:21:32 -0700
> From: Piotr Esden-Tempski <address@hidden>
> To: address@hidden
> Subject: Re: [Paparazzi-devel] New Autopilot board, lia/lisaM fork.
> Message-ID: <address@hidden>
> Content-Type: text/plain; charset=iso-8859-1
>
> Hi,
>
> A few random comments.
>
> On May 12, 2013, at 8:59 AM, address@hidden wrote:
>
> > I?m have done LIA, it?s near complete. Now i?m beginning with LISA, same size of LIA, bigger as actual lisaM.
> > Do you have other wishes ? Is someone on the list willing to test the board ?
> >
> > Differnces to previous LIA:
> > MPU-9150 footprint inside ASPIRIN footprint.
> Don't forget baro. And also be careful with that ... please don't bring back the i2c nightmare! Also reading out all the sensors with i2c will be probably at least on the verge of impossibility and will force you to use the invensense motion engine. Consider designing towards MPU-9250.
>
> > PA6H GPS module including external Antenna added.
> > Xbee socket added.
> I have not seen your design. But that sounds like a big space waste on the board.
> > possibly to reflow micro-SD card on the pcb.
> Good idea. Think about manufacturability...
> > Improvements on powering section.
> What does that mean? :)
> >
> > TODO:
> > remove USB connector.
> Why?
> > add usb protection circuit.
> What do you mean? If you mean ESD protection, then I think that is totally unnecessary in this application and just waste of space and weight. If you mean reverse voltage protection, please elaborate.
> > Added RS485 as lower cost bus option or instead of can
> I hope you mean ADD and not replace. CAN vs RS485 transceiver price difference is almost negligible. About 4cents a peace at 100 pcs... having a well defined protocol with filtering options and built in collision avoidance vs a custom protocol is in my opinion a better choice in most cases. But correct me if I am wrong.
>
> As I did not see your designs take my comments with a grain of salt. :) Sorry if I missed a link to your github or something. Are you putting them somewhere?
>
> Good luck with your project.
>
> Cheers Piotr