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by oscargomezf
Mon Jul 31, 2017 11:04 am
Forum: C/C++
Topic: Using RTS signal for enabling RS-485 transmissions in the raspberry pi 3B.
Replies: 0
Views: 436

Using RTS signal for enabling RS-485 transmissions in the raspberry pi 3B.

Hi everyone,

I'm working in an RS485 design with a raspberry pi 3B. I would like to use the RTS signal to enable/disable the transmissions.

Does anyone know how can I do that?

Is there any overlay for this purpose?

Best regards.
by oscargomezf
Wed Jul 19, 2017 11:39 am
Forum: Device Tree
Topic: Configuration GPIOs of an expander IO and from device tree
Replies: 2
Views: 1256

Configuration GPIOs of an expander IO and from device tree

Hi everyone, I'm using an expander IO: tca6424 from TI on my raspberry pi 3B and it's working perfectly. I'm using this device tree dts file: /dts-v1/; /plugin/; / { compatible = "brcm,bcm2835", "brcm,bcm2708", "brcm,bcm2709"; [email protected] { target = <&i2c1>; __overlay__ { status = "okay"; }; }; fragm...
by oscargomezf
Wed Jul 05, 2017 3:14 pm
Forum: Device Tree
Topic: Adding a new RTC to i2c-rtc-overlay.dts
Replies: 7
Views: 4863

Re: Adding a new RTC to i2c-rtc-overlay.dts

Hi PhilE, First of all, thank you for your help and your quick reply. Do you know what means this part of the .dts file? Probably, they are init values for the RTC, but I couldn't find any documentation about that: ... __overrides__ { ds1307 = [00 00 00 01 73 74 61 74 75 73 00]; ds3231 = [00 00 00 0...
by oscargomezf
Wed Jul 05, 2017 2:31 pm
Forum: Device Tree
Topic: Adding a new RTC to i2c-rtc-overlay.dts
Replies: 7
Views: 4863

Adding a new RTC to i2c-rtc-overlay.dts

Hi everyone, I'm trying to add new RTC driver, the ST41M62. I've added this code to the dts file i2c-rtc-overlay.dts : /dts-v1/; / { compatible = "brcm,bcm2708"; [email protected] { target = <0xdeadbeef>; __overlay__ { #address-cells = <0x1>; #size-cells = <0x0>; status = "okay"; [email protected] { compatible = "...
by oscargomezf
Tue Jan 17, 2017 5:26 pm
Forum: Advanced users
Topic: How to read an interrupt from user space from Raspberry Pi
Replies: 1
Views: 856

How to read an interrupt from user space from Raspberry Pi

Hi everyone, I'm using the reaspberry pi 3 with an IO Expander, the TCA6424A from Texas Instruments. I'm using this .dts overlay file: // Definitions for TCA6424A IO Expander from Texas Instruments for enyca-controller-v1 board /dts-v1/; /plugin/; / { compatible = "brcm,bcm2835", "brcm,bcm2708", "br...
by oscargomezf
Mon Jan 09, 2017 8:53 am
Forum: General discussion
Topic: Switch off WiFi/BT modules on Raspberry Pi 3B
Replies: 6
Views: 3216

Re: Switch off WiFi/BT modules on Raspberry Pi 3B

Thank you very much to everyone, I'm going to use the method proposed by gregeric: Using the blacklist and then force the gpios 128 (BT_ON) and 129 (WL_ON) to zero using the application rpi3-gpiovirtbuf. I've checked them and it seems to be no differences of power consumption between using the black...
by oscargomezf
Thu Jan 05, 2017 9:35 am
Forum: General discussion
Topic: Switch off WiFi/BT modules on Raspberry Pi 3B
Replies: 6
Views: 3216

Switch off WiFi/BT modules on Raspberry Pi 3B

Hi everyone, I'm working with the raspberry pi 3B on a buildroot 2016.02 distribution. Does anyone know how to disable WiFi and BT in the raspberry pi 3? I've read this one: https://www.raspberrypi.org/forums/viewtopic.php?f=63&t=138610&p=1072977&hilit=How+to+disable+the+Pi3%27s+WLAN+%26+Bluetooth+%...
by oscargomezf
Mon Dec 19, 2016 10:19 am
Forum: Compute Module
Topic: How to use uart1 (RXD1,TXD1)
Replies: 6
Views: 3115

Re: How to use uart1 (RXD1,TXD1)

Hi everyone,

I need two UARTs at the same time too, but I'm working on the raspberry Pi 3B instead of a compute module.
Do you know if I can try the same on a Raspberry Pi 3?

Best regards.
by oscargomezf
Fri Apr 29, 2016 7:36 am
Forum: Advanced users
Topic: devicetree overlay for MCP23017 GPIO expander
Replies: 66
Views: 17904

Re: devicetree overlay for MCP23017 GPIO expander

Hi Mike,

Right know I'm working on something similar to your project. I would like to add the SMBus IO Expander TCA6424A, and I need to build a .dts overlay for this purpose.

Could you upload the final .dts? I would like to check it.

Best regards.
by oscargomezf
Thu Apr 28, 2016 3:17 pm
Forum: Device Tree
Topic: Adding the Expander IO I2C TCA6424A
Replies: 0
Views: 1548

Adding the Expander IO I2C TCA6424A

Hi, I would like to add an i2c device, the expander IO TCA6424A to be controlled from the Linux kernel. 1º.- First of all, I made recompilation of the kernel, choosing the device TCA6424A like a module: Device Drivers > GPIO Support > I2C GPIO expanders > [M] PCA95[357]x, PCA9698, TCA64xx, and MAX73...
by oscargomezf
Sat Apr 09, 2016 2:13 pm
Forum: Troubleshooting
Topic: mkcard
Replies: 1
Views: 731

mkcard

Hi everyone, I've always used the a scrip based on mkcard.sh script: http://downloads.angstrom-distribution.org/demo/beaglebone/mkcard.txt to build my sdcard because I'm get used to working with buildroot. https://github.com/oscargomezf/raspberrypi_sd_tools/blob/master/mkcard.sh My host platform is ...
by oscargomezf
Tue Mar 15, 2016 10:45 am
Forum: Device Tree
Topic: Using i2c bus on device tree
Replies: 13
Views: 6175

Re: Using i2c bus on device tree

Hi PhilE, I've found a solution to my problem. I've changed the buildroot /dev management from Dynamic using devtmpfs only to Dynamic using devtmpfs + eudev View screenshot of buildroot /dev management: https://www.dropbox.com/s/xvhqty97x53arg6/buildroot_devtmpfs_eudev.png?dl=0 My config.txt file: ....
by oscargomezf
Mon Mar 14, 2016 2:11 pm
Forum: Device Tree
Topic: Using i2c bus on device tree
Replies: 13
Views: 6175

Re: Using i2c bus on device tree

No - I'm out of ideas (and time) at the moment. You could try a post on the interfacing forum linking to this thread, asking for suggestions. Ok PhilE, Thank you so much for everything. This is the link in the branch Interfacing (DSI, CSI, I2C, etc.) https://www.raspberrypi.org/forums/viewtopic.php...
by oscargomezf
Mon Mar 14, 2016 12:22 pm
Forum: Device Tree
Topic: Using i2c bus on device tree
Replies: 13
Views: 6175

Re: Using i2c bus on device tree

It is possible that the module aliases aren't being generated or copied correctly. They are the link between the compatible string and the module file. Try this: cd /lib/modules/`uname -r` grep i2c modules.alias | grep bcm2708 You should see output like this: alias platform:bcm2708_i2c i2c_bcm2708 ...
by oscargomezf
Mon Mar 14, 2016 11:34 am
Forum: Device Tree
Topic: Using i2c bus on device tree
Replies: 13
Views: 6175

Re: Using i2c bus on device tree

Hi PhilE, Ok then the .dts (.dtb) file is ok. (It was a ridiculous idea that this file was wrong, but I don't have any idea how this file is built). This is my etc folder. It doesn't exist the /etc/modprobe.d folder: # ls -l total 84 drwxr-xr-x 2 root root 4096 Jan 1 00:00 dropbear -rw-r--r-- 1 root...
by oscargomezf
Mon Mar 14, 2016 10:05 am
Forum: Device Tree
Topic: Using i2c bus on device tree
Replies: 13
Views: 6175

Re: Using i2c bus on device tree

I've just made other checks. Without dtparam=i2c_arm=on,i2c_arm_baudrate=200000 in the config file, when I've executed this command on the raspberry pi 2: # dtc -I fs -O dts -o /boot/temp.dts /proc/device-tree The part of the temp.dts file related to i2c: ... [email protected] { reg = <0x7e804000 0x1000>...
by oscargomezf
Mon Mar 14, 2016 9:25 am
Forum: Device Tree
Topic: Using i2c bus on device tree
Replies: 13
Views: 6175

Re: Using i2c bus on device tree

OK - the unusual name threw me. I'm awake now. One of your two modprobes is necessary if you want to use /dev/i2c* (not all applications need them), but the other one isn't. The i2c-bcm2708 driver module allows the kernel to access the Pi's I2C interfaces; this is sufficient to allow audio codecs e...
by oscargomezf
Mon Mar 14, 2016 8:42 am
Forum: Device Tree
Topic: Using i2c bus on device tree
Replies: 13
Views: 6175

Re: Using i2c bus on device tree

Your kernel is called zImage, which makes me think you haven't followed the kernel build instructions here . Without the mkknlimg step, the firmware doesn't know that the kernel is DT-capable so will pass it ATAGs instead. Hi PhilE, I'm using the zImage from the directory kernel-marked, so accordin...
by oscargomezf
Mon Mar 14, 2016 8:13 am
Forum: Device Tree
Topic: Using i2c bus on device tree
Replies: 13
Views: 6175

Using i2c bus on device tree

Hi, I'm trying to use the i2c bus of my raspberry pi 2 using device tree. I've just followed lot of examples in this forum. But I couldn't get it. I'm using buildroot-2016.02 and the config.txt file is: # Please note that this is only a sample, we recommend you to change it to fit # your needs. # Yo...
by oscargomezf
Fri Mar 11, 2016 4:36 pm
Forum: Device Tree
Topic: study on device tree on raspberry pi 2
Replies: 7
Views: 2343

Re: study on device tree on raspberry pi 2

Yes, in a sense that property is useless in the base .dts files, but I think it helps the reader to know which model the file is intended for, plus it matches other architectures which don't have the same involvement of the firmware. I complitely agree. I'm going to continue to learn how device tre...
by oscargomezf
Fri Mar 11, 2016 2:23 pm
Forum: Device Tree
Topic: study on device tree on raspberry pi 2
Replies: 7
Views: 2343

Re: study on device tree on raspberry pi 2

No, I really mean the firmware. The VPU (also known as the GPU) boots first, loads the .dtb, applies any overlays and parameters and some other settings - including the model string - then boots the kernel. This means that any model string you provide will be completely overwritten, so don't bother...
by oscargomezf
Fri Mar 11, 2016 11:56 am
Forum: Device Tree
Topic: study on device tree on raspberry pi 2
Replies: 7
Views: 2343

Re: study on device tree on raspberry pi 2

The firmware overwrites the Model string to include the board revision number. You can see the entire Device Tree at /proc/device-tree, which may help to remove doubt about what is happening. You can also see if the firmware encountered any problems with the DT using sudo vcdbg log msg |& grep -v -...
by oscargomezf
Thu Mar 10, 2016 4:11 pm
Forum: Device Tree
Topic: study on device tree on raspberry pi 2
Replies: 7
Views: 2343

study on device tree on raspberry pi 2

Hi, I'm trying to understand how works device tree on raspberry pi 2 [Raspberry pi 2 B v1.1 code: a01041]. I'm using buildroot-2016.05. I'm trying to modify the file bcm2709-rpi-2-b.dts from arch/arm/boot/dts: /dts-v1/; /include/ "bcm2709.dtsi" / { compatible = "brcm,bcm2709"; model = "Raspberry Pi ...

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