Currently working on a project that requires me to use two I2C devices on the Raspberry Pi, but both devices use the same address. Does anyone have an easy fix to changing the address of 1 of the devices? :)
No, most devices don't allow changing the address. Those that do have a separate pin (or pins) that can be used to select the address. Very few devices allow changing the address by software. If you said which device you use, we could tell you which group it belongs.
However, there's a quite easy workaround: The Raspberry Pi has up to 6 I2C busses, so you can just use a second bus for the second device (like the one on GPIO0/1, which is already configured as I2C bus 0 by default and typically unused)
Related
I am currently building an app that controls a single actuator and a LED strip. The controller for the actuator and LED strip is based on an ESP32.
On the ESP32 I have used the <ESPAsyncWebServer.h>, <ESPAsyncWiFiManager.h> to set up and connect the ESP to the local wireless network. In the app I would like to send some commands to the ESP like http://<ESP32_IP>/led_set?level=<level> and
http://<ESP32_IP>/act_open and so on, this shouldn't be an issue.
Normally I would set up mDNS on the ESP and in the Flutter app, however several of the ESP controllers are already shipped to the customers. So I am looking for another way to identify the ESP.
At the moment I have used the ping_discover_network library and the ESP shows up fine on port 80. I am however not able to separate the ESP from the other devices that shows up on port 80.
Do any of you have any suggestions?
Thank you in advance
You don't have many good options. If you only want to identify a few devices which have slipped through your fingers without mDNS, you can use their MAC address as a filter. If you happen to know their individual MAC addresses, then that should be quite painless. Otherwise you'd have to look for devices with MAC OUI (first 3 bytes, usually) ranges allocated to Espressif. Espressif has several OUI ranges, but if your devices were from a single batch of ESP32 module of the same type, they'll be using the same OUI so it should be quite easy to figure out.
E.g. a batch of modules I have all start with 40:F5:20:...
Of course, if a third party installs their (unrelated) ESP32 module into the same network, you'll have a chance of identifying those as well, but such is life.
This is obviously a stop-gap measure. Make sure further devices go out of door with some identification (mDNS or otherwise).
I'm writing a device driver for multiple devices, especially FPGA board.
I want a single driver to drive multiple devices.
In this case, how can I differentiate the devices in the code?
By minor number? PCIe address?
Thanks,
I am porting an I2C driver to Linux-4. This device provides multiple I2C addresses for different function simultaneously.
For example:
address 0xAA is for access of SPI flash.
address 0xA0 is for access of EEPROM.
address 0x60 is for normal access (control purpose).
Is it possible to support access of different I2C address in single-one I2C device driver?
Any help appreciated,
Thanks
I think it is possible. Using i2c_transfer() you are giving particular address in i2c_msg structure of the device you want to communicate with. So your driver will be able to communicate with all of the functions of your i2c device.
Depends on what type of I2C driver you are talking about, bus(adapter) or chip(client) driver?
i2c-dev.c is a kind of bus driver with character device interface which exports kernel low level I2C API to userspace.
For each registered I2C adapter Kernel will add i2c-N device node in /devuserspace interface.
But you can't read/write EEPROM chip attached to /dev/i2c-N like simple character device or file. You need to write some utility program regarding chip protocol.
But in Linux there is are special EEPROM chip drivers like eeprom.c or at24.c for registering I2C EEPROM devices with addresses of 0x50..0x57(if I'm not wrong) to Kernel and creating files in /sys userspace interface.
You can access them as a file in:/sys/bus/i2c/devices/0-005x/eeprom
Thanks for Dražen Grašovec and user2699113 's help.
I am porting a I2C device driver (chip, client) to Linux-4.9.
This chip accepts different I2C device address for different purpose.
My goal is to create only one I2C device on Linux device tree file (.dts)
I resolved my issue by using i2c_new_dummy().
In driver probe function,
I made two i2c_new_dummy() to create two additional i2c clients.
One(client#1) is for accessing of I2C address 0xAA, another(client#2) is for I2C address 0xA0.
So I can use client#1 to communicate with its SPI flash and use client#2 to access it EEPROM.
We have several devices connected to Modbus network. We bought a new device that can't be tuned and has fixed settings: baudrate=19200, parity=odd, while others have baudrate=38400, parity=none. Is it possible to use them in one network, i.e. first read from old devices, and then reset serial port to read from the new device?
Yes, as long as the devices ignore data encoded with the wrong baud rate.
I plan to extend the range of my Wifi with my Notebook. - My question to this, is it possible to build a wireless repeater with only one NIC? or do I really need at least two NICs, one for being logged in and receiving the packets and the other for extending the WiFi/Signal. - Actually, what I wanna do is, using my laptop as a WiFi-Repeater, but only with the built-in NIC, no second one.
I've searched the net already but found nothing about the functionality of a WiFi-Repeater and if they have two NICs integrated.
Hope you guys can enlight me ;)
EDIT(added schemes):
Possibility A
Possibility B
What can be achieved with an AP capable Chip/Firmware, for instance, the Ath9k.
You can't turn laptop's WiFi into range extender, since I believe it requires a special WiFi chip firmware and a special configuration of antenna(s).
However, you might try to look on the internet if WiFi chip you have supports AP mode in firmware (not all manufacturers provides that), and if yes, you can set up the access point with the same SSID. In this case your WiFi clients will roam from one AP to another. Of course, this kind of setup requires Ethernet cable attached to your laptop.