SAMA5D27-SOM1-EK1 PINs configurations

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ghasseenn
Posts: 6
Joined: Wed Jun 10, 2020 4:10 pm

SAMA5D27-SOM1-EK1 PINs configurations

Wed Jun 10, 2020 4:45 pm

Hello,

I am using SAMA5D27-SOM1-EK1 embedded board which I build for it Linux minimal kernel image using Yocto project.

I want to exploit ISC J27 connector PINs ( user guide page 31 ; 4.3.2 Image Sensor (ISC) Interface ) :

http://ww1.microchip.com/downloads/en/D ... 02667A.pdf

This connector is realted to PIOC pins.

Checking this PINs features I find that they are used for many functionalities as I find in the SAMA5 SOM datasheet ( Page 11 : table 4.3 ) :

http://ww1.microchip.com/downloads/en/d ... 01521a.pdf

I want to know how can I check the real feature of the PIN and for what is used for at the moment ? For example, let's take PC12 of the above SAMA5 SOM datasheet table, is it used as ISI_D3 or URXD3 or TK0 or A1 ? By the way, what is meaned by A1 functionality ?

I can find in the SAMA5D27 SOM1 user guide page 49, Figure 7-3. PIO Muxing Table, that it is used as ISC_D3. Is from this table can I see the features of my board PINs ?

Besides, how can I change this feature ? For example, moving from ISI_D3 to URXD3 ? What should I do ?

My goal is to use that ISC J27 connector to make a simple wiring circuit with LED and PUSH Button and .NET core program to test this Interface GPIOS. Should I change the configurations or leave it as ISC Data Pins if it's the actual functionality ?

Thank you
blue_z
Location: USA
Posts: 2154
Joined: Thu Apr 19, 2007 10:15 pm

Re: SAMA5D27-SOM1-EK1 PINs configurations

Wed Jun 10, 2020 9:04 pm

ghasseenn wrote: I want to know how can I check the real feature of the PIN and for what is used for at the moment ?
That depends on what software you use on the board.
If it's Linux and the debugfs is mounted, then the pseudo-file /sys/kernel/debug/pinctrl/pinctrl-handles lists the pins multiplexed for each active peripheral.

ghasseenn wrote: For example, let's take PC12 of the above SAMA5 SOM datasheet table, is it used as ISI_D3 or URXD3 or TK0 or A1 ?
That document refers you (in section 2) to the SAMA5D2 SoC datasheet, which has a complete description of pins (section 6) and the multiplexing capability of the PIO controller (section 33).

Regards
ghasseenn
Posts: 6
Joined: Wed Jun 10, 2020 4:10 pm

Re: SAMA5D27-SOM1-EK1 PINs configurations

Thu Jun 11, 2020 10:43 am

That depends on what software you use on the board.
I am using 4.14.73-linux4sam-6.0 Linux kernel that I build with Yocto project
If it's Linux and the debugfs is mounted, then the pseudo-file /sys/kernel/debug/pinctrl/pinctrl-handles lists the pins multiplexed for each active peripheral.
when I boot the board and try to open the file using

Code: Select all

vi /sys/kernel/debug/pinctrl/pinctrl-handles
command, the file opens but nothing is there, just blinking cursor
ghasseenn wrote: For example, let's take PC12 of the above SAMA5 SOM datasheet table, is it used as ISI_D3 or URXD3 or TK0 or A1 ?
That document refers you (in section 2) to the SAMA5D2 SoC datasheet, which has a complete description of pins (section 6) and the multiplexing capability of the PIO controller (section 33).
Well , this did not help me! In fact, I have found that the complete description of pins and their capabilities, but, I did not find what is its actual current functionality now

Regards
[/quote]
ghasseenn
Posts: 6
Joined: Wed Jun 10, 2020 4:10 pm

How to change PIN features in SAMA5D27-SOM1-EK1 board

Thu Jun 11, 2020 1:37 pm

I am using SAMA5D27-SOM1-EK1 Microchip embedded board. I am using Linux kernel 4.14.73 version that I build using Yocto project.

That board has a J27 connector that is used as Image Sensor Interface as shown in 4.3.2 Title, page 31 from the board user guide document, besides, Table 4-16. ISC Connector J27 Pin Assignment, page 32, shows the connector PIN features.

This is a link to the board document :

http://ww1.microchip.com/downloads/en/D ... 02667A.pdf

My goal is to change some PIN features of this connector, in order to use it as GPIO PIN, that I will use in order to make a simple wire circuit with a PUSH BUTTON and LED. I think that I must not let it as ISC data pins.

I think that I must change something in the board device-tree which you can find here :

https://elixir.bootlin.com/linux/v4.14. ... om1_ek.dts

But I don't know what to change and how ? I just want to have 2 GPIO PINS , one for input and the other as output.

Please help me out ? I will be grateful !
blue_z
Location: USA
Posts: 2154
Joined: Thu Apr 19, 2007 10:15 pm

Re: How to change PIN features in SAMA5D27-SOM1-EK1 board

Fri Jun 12, 2020 12:53 am

ghasseenn wrote: But I don't know what to change and how ?
As I and others have already told you (or to your various aliases) on this and other forums/channels (e.g. this post) many times over the past ten (?) months, you need to modify the Device Tree of the board.

ghasseenn wrote: I just want to have 2 GPIO PINS , one for input and the other as output.
Study this post and this post, and the kernel documents mentioned within.
IOW kernel drivers already exist for using GPIOs with LEDs and buttons.

Regards

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