Microchip Arduino thing interview questions?

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Re: Microchip Arduino thing interview questions?

Postby hlipka » Thu May 26, 2011 2:15 pm

I would like to know which peripherals, and which functions of these, are already suppoerty OOB by the provided Arduino IDE. I'm thinking of stuff like ethernet (as mentioned before), the 2 CAN channels and the USB OTG functionality. (And vice versa - which functions require me to use MPLAB?)

Also, when someone is developing a new shield for the Arduino, how easy is it to have the software ready for both platforms? Is it just a matter of recompiling, or are there specific changes needed?
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Re: Microchip Arduino thing interview questions?

Postby tcmichals » Thu May 26, 2011 4:15 pm

The issue with adding a PicKit3 to openocd is the protocol, how it maps commands from ISCP to JTAG bus. And the command set provided via USB. There is some docs, but it would be nice to have the complete firmware source code. Then from there, it can be done. I'm using openOCD with JTAG on the PIC32, but it is different pins, would like to use the standard ISCP to JTAG. According to the documentation, no reverse engineering is allowed... Thus the issue...

Also, would be nice to have the source on the PIC32 exception handling for debugging. There is code in the bootloader to handle this.

Overall, my understanding is
- The tool group is a revenue generating group, if they have open source then this may cause revenue issues.
- If the code is open source, DIY will get themselves into problems and create a large number of support requests to microchip.

I'm a DIY, having a rope is the best part of using ARM parts. Using PIC32, have to weave the rope, make the chair to stand on etc, but, because the code cannot be shared. Using an ARM we have all of the source, in fact an ARM company allows their library to be used on other ARM parts. Microchip does not.

90% of the people will look at the code and not even use it...
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Re: Microchip Arduino thing interview questions?

Postby jamodio » Thu May 26, 2011 4:42 pm

schazamp wrote:I was looking at the schematic and board layout, and it looks like they are using the FTDI FT232RQ (USB to Serial) chip. My question is, why didn't they use the built-in USB (on the Max32) or one of the PIC-based USB-serial converters (eg., 18F2550, 18F24J50) (for the Uno32 and/or the Max32)? The PICs seem relatively easy to source, and somewhat cheaper to me.


Just to add a datapoint. Microchip has also its own RS232<->USB converter which is the MCP 2200 (based on the PIC18F14K50), simliar to the FTDI chip. Its a fairly new part and there is a breakout board designed by DP but it is not longer available from Seed Studio.

http://dangerousprototypes.com/docs/MCP2200_breakout_board

Cheers
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Re: Microchip Arduino thing interview questions?

Postby Zeta » Thu May 26, 2011 9:45 pm

While Chipkit boards are great some of us already have Pic32 Starter Kits. Will I be able to use The chipkit enabled Arduino enviroment with Pic32 starter kits?
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Re: Microchip Arduino thing interview questions?

Postby jamodio » Thu May 26, 2011 10:39 pm

Zeta wrote:While Chipkit boards are great some of us already have Pic32 Starter Kits. Will I be able to use The chipkit enabled Arduino enviroment with Pic32 starter kits?


As is out of the box probably not. On the PIC32 SKs there is another PIC in the middle serving the USB interface and acting as programmer/debugger, on the other hand the "Arduino like" have a FTDI USB-Serial converter communicating with a serial bootloader preprogrammed on the PIC32MX.

Then to use the Arduino environment you will need at least to add the required hardware and program the serial bootloader on the PIC32MX.

I didn't check yet the code or the new boards (taking for ever to arrive) but I assume that there are no pin or configuration conflicts.

My .02
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Re: Microchip Arduino thing interview questions?

Postby voidptr » Fri May 27, 2011 3:07 am

this is really interesting :-)

i recently bought an AtMega1280 and few shields because it was easy to start to do something for some demo... the possibility to have a bigger 32 bits cpu is welcome and i can surely use it !

now of course we got a lot of good questions for michochip about their licenses, sources, libraries and compilers.
i guest some stuff will be really open, like their port of the Arduino IDE, low layer cpu glue, mid layer lib for the pic32 support, bootloader source, and some other lib ? with source code ?

but what will happen on the standard pic development side... license and sources of tcp stack, usb stack ... , libraries and source code ....
i'm not sure they will change something their ... ( but of course i wish they will :-))

anyway

@Ian , you will have a lot of good questions to ask michochip ! i wish you (we) to get answers and maybe, good news for the open world !

anyway it is interesting, i will follow this suject ! and maybe order the big arduino pic myself :o)
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Re: Microchip Arduino thing interview questions?

Postby ian » Fri May 27, 2011 3:48 am

Interview is 10am CST. I will ask to record it and post if all goes well. I should have the final question list and a few notes posted today, probably more info next week.
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Re: Microchip Arduino thing interview questions?

Postby makomk » Fri May 27, 2011 4:54 am

ian wrote:I'm gonna ask about 5volt issues (pic 32 is 3v3), and request PPS on pic32. But mostly I want to ask why they're freeloading on open source, but keeping their special sauce to themselves ;)
https://github.com/chipKIT32/chipKIT32- ... icense.txt


Yeah, especially since as far as anyone can tell the compiler is basically a rebranded version of gcc-mips with copy protection added that disables optimisation levels above -O1 unless you fork out lots of money to Microchip. (Yes, this includes the standard optimisations developed by the GCC developers, including platform-independent ones.)

tcmichals wrote:The issue is not the gcc compiler, it is the PCI32 libraries, I was changing them to use standard gcc pragma's etc.


That's my understanding of the problem too - as soon as you modify or even just recompile the gcc source they provide, you're not allowed to use their PIC32 libraries with that compiler. Nice end run around open source there.

(Not even going to bother asking a question; I'm sure Ian will do his best to quiz them about this.)
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Re: Microchip Arduino thing interview questions?

Postby StsChaZs » Fri May 27, 2011 7:16 am

I see that you have added headers for a lot of the IOs of the PIC. But they are placed in a pretty uncomfortable way, is there going to be a revision were these pins will be placed in a different place so there easier to access with a shield on top?
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Re: Microchip Arduino thing interview questions?

Postby tcmichals » Fri May 27, 2011 7:47 am

"Why is code under such a license? Did Microchip require this?
Last edited by tcmichals on Fri May 27, 2011 8:26 am, edited 1 time in total.
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Re: Microchip Arduino thing interview questions?

Postby ian » Fri May 27, 2011 10:21 am

I think they gave me the wrong time, they didn't convert to my time zone correctly. I've been listening to elevator music for 20 minutes, then the conference ended automagically.

I reviewed your marketing stuff, looked through the source code, PCB files, and sample boards. It seems like what you have is
*an ar-dween-o shaped PIC32 development board
*The hardware is 32bits and way beefier than an ar-dween-o
*and both boards are, what 10 bucks cheaper than a similar ar-dween-o?

The twist, what separates you from the other 3.3volt ardweeno-wanna-bes, is
*you hacked the original ar-dween-o development software to support your PIC processor
*ar-dween-o sketches compile and run on the PIC without any changes,
*beginners use the same ar-dween-o client they already know and love.
*Anything I left out?

Why is Microchip entering the Ardweeno fray? Why get involved now?

How do you take advantage of the speed and the extra capabilities of a PIC32 in existing arduinio projects?
--Any suggestions to port libraries with strict timing requirements?

The PIC on the Max32 boasts USB 2.0, CAN, and 10/100 Ethernet MAC. Are these already supported by open source libraries with MPIDE?
--Microchip already supplies excellent drivers for this hardware, but the licenses don't allow sharing, which is a big part of the ar-dween-o community. Do you have any suggestions for users who want to make projects that support the USB, CAN, or Ethernet and share their code?

Your guy, Mark I think I saw comment in Hack a Day comments, put a lot of work into adding the multiplatform support to the Ar-dween-o IDE. Is Microchip working with the ar-dween-o crew to unify efforts?
*when the ar-dween-o team releases a new version of the IDE what will be the lag for an updated chipKIT MP(multiplatform)IDE?

A big part of the ar-dween-o buzz is the open source community and open source contributions. You mention that big base of support as an advantage in your press material.
*Does microchip have an obligation to give something back, and what is Microchips contribution?

What's the difference between the ChipKIT compiler, and the C32 compiler?
*both based on GCC, but C32 has optimization restrictions after a 60 day demo
*I understand chipkit supports C++?

I was perusing your git source repository, and I wanted to take a look at the compiler source.
https://github.com/chipKIT32/chipKIT32- ... icense.txt
I only found a license file, and it forbids modification and redistribution.
*What advantages do you get from keeping that part of the system closed?
*Is it consistent with the spirit of the community you're trying to work with?

Can we talk a little about shield compatibility.
*chipKIT is a 3.3volt system, and most shields are designed with 5volt IO in mind.
*The PIC pins are 5volt tolerant, but what about 5volt inputs that need 3.7volts or more?

Ruggedcircuits.com notes a few issues with the pinout:
*there's no PWM on D11 so it doesn't work with their rugged motor driver
*also, the PIC doesn't have interrupts on every pin
*Why not PIC 24 with PPS?
*Any plans for PPS on pic32?

Do you plan to track shield incompatibilities?


Here's a condensed list of questions from the forum I'll try to cover. I have a feeling they want to walk through a power point, but I won't have that at 6pm on a Friday :)
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Re: Microchip Arduino thing interview questions?

Postby Markus Gritsch » Fri May 27, 2011 10:30 am

Excellent compilation, Ian. I'm very keen on the answers :)
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Re: Microchip Arduino thing interview questions?

Postby pingbat » Fri May 27, 2011 11:27 am

Power Point: I have the Power (the pointer) and i'm going to point it at this slide while I read bullet points out loud.

Why aren't you paying attention?!
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Re: Microchip Arduino thing interview questions?

Postby ian » Fri May 27, 2011 12:12 pm

Your guy, Mark I think I saw comment in Hack a Day comments, put a lot of work into adding the multiplatform support to the Ar-dween-o IDE. Is Microchip working with the ar-dween-o crew to unify efforts?

Yes, post v1.

*when the ar-dween-o team releases a new version of the IDE what will be the lag for an updated chipKIT MP(multiplatform)IDE?

Development version is kept at parity with the main trunk

The PIC on the Max32 boasts USB 2.0, CAN, and 10/100 Ethernet MAC. Are these already supported by open source libraries with MPIDE?

Not yet. Want it to be open source. Just core library support for now.


--Microchip already supplies excellent drivers for this hardware, but the licenses don't allow sharing, which is a big part of the ar-dween-o community. Do you have any suggestions for users who want to make projects that support the USB, CAN, or Ethernet and share their code?

A shield with USB and ethernet are coming, we wish them luck. Community can come up with it, how long will it take?Port LUFA. Corporate guys see source changes as bug not a feature.

How do you take advantage of the speed and the extra capabilities of a PIC32 in existing arduinio projects?
Computational things are faster, maker faire Mandelbrot LCD graphic demo
--Any suggestions to port libraries with strict timing requirements?
Some potential to use a separate clock on peripherals.

What's the difference between the ChipKIT compiler, and the C32 compiler?
*both based on GCC, but C32 has optimization restrictions after a 60 day demo
*I understand chipkit supports C++?
No restrictions, all optimizations, no debug. ?

I was perusing your git source repository, and I wanted to take a look at the compiler source.
https://github.com/chipKIT32/chipKIT32- ... icense.txt
I only found a license file, and it forbids modification and redistribution.
*What advantages do you get from keeping that part of the system closed?
*Is it consistent with the spirit of the community you're trying to work with?
Is open source, in different github. Different compiler than C32, called chipkit compiler instead.Putting everything out under the same license. Giving to community. If you see other licenses tell us, we'll fix it.

Can we talk a little about shield compatibility.
*chipKIT is a 3.3volt system, and most shields are designed with 5volt IO in mind.
*The PIC pins are 5volt tolerant, but what about 5volt inputs that need 3.7volts or more?

Ruggedcircuits.com notes a few issues with the pinout:
*there's no PWM on D11 so it doesn't work with their rugged motor driver
*also, the PIC doesn't have interrupts on every pin
(not a well formulated question, my bad)
*Why not PIC 24 with PPS?
Possibility, 32 bit to start
*Any plans for PPS on pic32?
See us in 6 months

Do you plan to track shield incompatibilities?
Start a thread in the chipkit forum

A big part of the ar-dween-o buzz is the open source community and open source contributions. You mention that big base of support as an advantage in your press material.
*Does microchip have an obligation to give something back, and what is Microchips contribution?

----This was a lead in question to the other stuff, but there was an earlier opening so I didn't need to ask it.

I'll clean up the audio and post it in a second.
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Re: Microchip Arduino thing interview questions?

Postby ian » Fri May 27, 2011 1:49 pm

Audio file, edited to remove banter and cross talk. Unedited audio available if there is a controversy :) Will try to make a smaller embedded version by next week.

http://dangerousprototypes.com/files/DP ... hipKIT.mp3 [13mb]

EDIT: uploaded new version with ID3 tags and single channel audio.

GCC source link:
https://github.com/chipKIT32/chipKIT-cxx
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