what GPIO is the octo really consuming, conflicting information between forum and dtoverlay

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Dloranger
Posts: 8
Joined: Tue Jan 02, 2018 2:10 pm

what GPIO is the octo really consuming, conflicting information between forum and dtoverlay

Post by Dloranger » Thu Feb 08, 2018 4:06 pm

In looking at the device tree overlay, it would appear that the following GPIO are being used 0, 12, 24,36

gpio = "/fragment@2/__overlay__:mult-gpios:0",
"/fragment@2/__overlay__:mult-gpios:12",
"/fragment@2/__overlay__:mult-gpios:24",
"/fragment@2/__overlay__:mult-gpios:36",
"/fragment@2/__overlay__:reset-gpios:0";

however according to this post, the GPIO being used are 5, 18, 19,20,21,22,23,24,27
http://forum.audioinjector.net/viewtopic.php?f=9&t=1317

For I2S :
pin 12 : Bit clock (GPIO18)
pin 35: LR clock (GPIO19)
pin 38: Data in (GPIO20)
pint 40: Data out (GPIO21)

For codec controls :
GPIOs : 27, 22, 23, 24, 5

So I don't actually know what pins to actually stay away from in my designs. Can you please clarify what GPIO are actually being used on the octo?

Dloranger
Posts: 8
Joined: Tue Jan 02, 2018 2:10 pm

Re: what GPIO is the octo really consuming, conflicting information between forum and dtoverlay

Post by Dloranger » Thu Feb 08, 2018 4:15 pm

Part of the reason I am digging into this is I am getting erratic behavior from my boards, and I think there might be a gpio conflict, but I just can't tell from the information online.

the Octo does not always load up with the overlay, although I can still see it when running i2cdetect tools. other times I get it to load up just fine and I get other odd behavior from my system, specifically from I2c GPIO expanders, these are using GPIO 12/16/25 in addition to the I2C bus.

flatmax
Posts: 603
Joined: Sat Jul 23, 2016 11:39 pm

Re: what GPIO is the octo really consuming, conflicting information between forum and dtoverlay

Post by flatmax » Sat Feb 24, 2018 1:41 pm

Hi there,

Here is the dts reference :

Code: Select all

https://github.com/raspberrypi/linux/blob/rpi-4.9.y/arch/arm/boot/dts/overlays/audioinjector-addons-overlay.dts
Which says :

Code: Select all

			mult-gpios = <&gpio 27 0>, <&gpio 22 0>, <&gpio 23 0>,
				     <&gpio 24 0>;
			reset-gpios = <&gpio 5 0>;
THis post you reference :

Code: Select all

http://forum.audioinjector.net/viewtopic.php?f=9&t=1317
Says :

Code: Select all

For codec controls :
pins : 13, 15, 16, 18, 29
GPIOs : 27, 22, 23, 24, 5
Seems accurate to me !

Matt
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