Electrical Schematics

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Electrical Schematics

Postby dgrinblat » Wed Feb 11, 2015 2:27 pm

Hello,

I am looking to write drivers for the WandBoard, but my main area of expertise is in software development, so I do not have any knowledge of how to read or use electrical schematics. Does anyone have a good resource that explains the format used in the WandBoard schematics and/or how to utilize this in code? Any help would be greatly appreciated.
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Re: Electrical Schematics

Postby Tapani » Fri Feb 13, 2015 8:04 am

The schematics are standard circuit diagrams.

From a software point of view, the schematics come handy for
  • knowing which signals go where (for instance, which CPU pins the component uses, which can determine interrupt numbers etc)
  • see the exact model number of components (often stated just below the component)
  • debugging, you can use a volt-meter to measure signals from resistors etc, and compare with what you'd expect to see
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Re: Electrical Schematics

Postby blackt1ger » Fri Apr 03, 2015 11:23 pm

Sorta the same issue here. I got the Rev B1 schematics, but have a Rev C1 Quad board. Can't seem to find the C1 Schematics. (just got it from Digikey this week).

Would be nice to see a bit of GPIO/I2C/SPI demo code.
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Re: Electrical Schematics

Postby Tapani » Tue Apr 07, 2015 12:24 pm

I'll see what I can do regarding C1 schematics. The difference is mainly a changed Wifi chip.

Regarding demos for GPIO / I2C -- what are you looking for?
There is some information how to pull the GPIOs on the external pinheader up and down at http://wiki.wandboard.org/External_gpios
For I2C, you can always play around with i2cutils:
Code: Select all
i2cdetect -y 0
i2cdetect -y 1
i2cdetect -y 2

Will probe I2C1, I2C2 and I2C3 for devices.

Commands to write / read from I2C addresses are
Code: Select all
i2cset -y 0 0x50 0x10 0xaa
i2cget -y 0 0x50 0x10

Writes 0xaa to register 0x10 of the device at address 0x50 on bus 0 (I2C1).
The second command reads that register.
(These commands can be used to write and read a byte in a small EEPROM on address 0x50)
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Re: Electrical Schematics

Postby blackt1ger » Wed Apr 08, 2015 12:02 am

Thanks. I found the schematics. (Can't quite remember where, though. :) Now to start building kernels. :) Starting a new thread, I hijacked this one enough.
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Re: Electrical Schematics

Postby stefano2015 » Wed Apr 08, 2015 11:02 am

Interesting stuff. Thanks:)
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Re: Electrical Schematics

Postby greanie » Mon Jun 01, 2015 9:22 am

Can someone point me to the schematics? I'm looking to add an I2C line and haven't found anything in the wiki or the homepage.

Thanks!
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Re: Electrical Schematics

Postby Tapani » Mon Jun 01, 2015 10:16 am

Check the downloads section at www.wandboard.org

There are I2C signals on the pinheaders.
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