As pointed out by @Andyroo, the chip is not the same chip described for the tutorial I was using.
For those who may be in the same situation, try this tutorial:
The address of the board connected to your Pi is 27(hex) and not 20(hex).
The row shows the most significant digit and the column shows the least significant digit of the address in hex.
Going by Amazon, this is the default for the PCF8574T chipset on this board but looking at the pictures, one of the interface cards have a set of three address pins that ...
I'm also using 20.04 on Raspberry Pi 4s. After googling around, there is a config.txt at /boot/firmware/config.txt and the following example worked for me in that file:
The problem is that I was sending the wrong data array to the OLED for printing.
In functions writeString() and writeDisplayByte() , the last printf statement is printing OLED::doubleScaleBuffer whereas the correct array, containing the BYTE_STREAM command is writeBuffer.
So the correct statement should be:
printf("%d\n", write(OLED::fd, writeBuffer, ...
MCP23017 is an I2C I/O expander.
According to datasheet VDD, supply voltage goes from 1.8 to 5.5V while VSS is ground.
So it would be possible to run those chips at both 3.3V and 5V both have pros and cons.
Running at 5V
PRO: feeds directly from the (powerful) +5V rail
CON: you will need to level-shift your I2C (for I2C open drain it's just a matter of ...
Turns out that above DTS file is correct apart from the address that should be 0x38. Wake interrupt line was pulled low and the controller was hibernating hence the 0x35 address. After fixing the interrupt line and correcting the address touchscreen works like it should be. Here is corrected DTS file for reference:
// Definitions for FocalTech System ...
There is not enough information about the first sensor. I do not see any mention of the interface used.
The second sensor uses I2C so that it can be connected to the Pi's I2C bus.
I see no way of changing the second sensor's I2C address. That means that if you want to connect more than one you will need
to use an I2C multiplexor chip as well
or use one ...
There was not much documentation on the those sites (at least that I could read), so I am just giving you general information.
Most sensors that use I2C communication to talk to the pi, have the ability to select the devices address. This allows you to have two sensors that you can talk to separately.
If the device uses SPI communication, you would use ...
I use it in pigpio so it certainly works.
Perhaps have a look through the code on GitHub.
I remember needing to declare some structures when the code was first written as the Linux development files seemed incomplete.
It turns out my logic level converter is probably faulty, but not necessary anyway. Connecting the I2C directly to 3.3V, GND, SDA, and SCL on the Pi solved the issue, I can now detect the module at the expected address.
I'm using Ubuntu Server 20.04 LTS. The dtparams setting does not work, instead you need a udev rule.
The fan config is in /sys/class/thermal/cooling_device0/, if you cat /sys/class/thermal/cooling_device0/type, it should be "rpi-poe-fan".
Once you've confirmed that, use this udev rule as an example:
# If the ...
The OP has setup and successfully detected an I2C MAX30100 Pulse Oximeter and Heart-Rate Sensor module. But when trying to read the sensor, he encounters two problems:
(1) Gets the "Exception remote I/O error [error 121]",
(2) Gets only zero values for the red LED and IR Led outputs.
How to fix it?
Body is limited to 30000 ...