CraigV
Posts: 31
Joined: Tue May 21, 2013 11:45 am

Slight Difference between Wheezy and Jessie spi drivers

Thu Oct 08, 2015 10:13 pm

When I updated to Jessie, I no longer was able to program the ATmega328P on the Gertboard. I had been using my own python program to upload the .obj code from the avra assembler to the ATmega328P using the connections shown in the Gertboard instructions (page 43). It seems that in Wheezy, my program was able to override the spi driver control of GPIO8 using a GPIO output command so that GPIO8 was held low for the entire time the code was being uploaded. With the Jessie driver, it appears that I need to use GPIO7 instead of GPIO8 for uploading programs because the Jessie driver raises GPIO8 occasionally causing the ATmega328P to start executing the partial code. The RESET line which enables programming of the ATmega328P must remain down for the entire upload.

I don't know whether this problem affects avradude since I have never used it.

My explanation might not be right, but what is clear is that the two drivers do things slightly differently and the differences can affect programs after an upgrade to Jessie.

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NormanDunbar
Posts: 111
Joined: Wed Nov 23, 2011 12:13 pm
Location: Leeds, West Yorkshire, England.
Contact: Website

Re: Slight Difference between Wheezy and Jessie spi drivers

Fri Oct 16, 2015 8:52 pm

Evening,

I think this breaks RasPiDuino as well. Under Wheezy everything worked. Under Jessie, I get verification errors all the time. I'm reverting back to Wheezy on Monday and retesting to be 100% sure that it's Jesse.

Cheers,
Norm.
Why do they put lightning conductors on churches?
Why did Tarzan never have a beard?

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NormanDunbar
Posts: 111
Joined: Wed Nov 23, 2011 12:13 pm
Location: Leeds, West Yorkshire, England.
Contact: Website

Re: Slight Difference between Wheezy and Jessie spi drivers

Sat Oct 17, 2015 3:37 pm

Oops! PICNIC. I should have "uploaded using programmer" and not just hit the upload button. Problem solved for me.
Why do they put lightning conductors on churches?
Why did Tarzan never have a beard?

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