Now i want to implement the HSPI on core1 for an ADXL345 accelerometer. I have this sketch that i'am trying to implement but this is not working for some reason. I always get 0,0,-1 results on the serial. If I recall correctly, the ADXL345 isn't a pure SPI interface as it can switch between SPI and...

@machiel, nice contribution! I've wondered how to include jquery into an embedded webserver. Thanks for showing us a way.

Also, why use 2 IO pins when you can use one to do the same thing. Tie REED_NC to +3.3v, and tie REED_NO to GND. From the Com. side of the reed (the side you have going to 10k then to +3.3v) take that to your input pin. Good suggestion, but considering that the reed switch will always be positioned...

It is imperative to use the default GPIO's for the LoRa RFM95W module viz: GPIO5 -- SX1278's SCK GPIO19 -- SX1278's MISO GPIO27 -- SX1278's MOSI GPIO18 -- SX1278's CS GPIO14 -- SX1278's RESET GPIO26 -- SX1278's IRQ (Interrupt Request) HSPI cannot be used with TFT_eSPI library as LoRa uses GPIO 14 f...

It seems to me that sharing hardware pins between the two cores is inviting disaster. Either you need to use semaphore locks or use totally separate pins. The access to the display is probably synchronous and manageable (if data transfers are kept small). Since the LoRa code is probably interrupt dr...

@Zeni241, what latching solenoid are you using that operates on 3V? What is the solenoid activating?

I have circuits for operating latching solenoids but these usually require much more than 3V to switch (typically 9V or greater).

I agree with @bobtidey, definitely use a 10X probe while probing clock signals, but also, for I2C, I would not recommend any pullup resistor above 5K.

Another reason to use pre-existing modules in a product is that it is easier to get FCC, etc. approvals if you're using a module that is already approved.

Besides buffering, a simple technique to lower the impedance of the Analog source (if its slowly varying, like a Pot), is to add a capacitor between the analog input and ground. Typically a 100nF cap is more than enough to help stabilize the readings.

Also, what is the reason for using a buck converter in the reference design? Why wouldn't a regular LDO work? I used the MIC5219-3.3 extensively in many of my designs for battery powered projects in the past. Am I doing something wrong all this while with just using a standard LDO? I'm not familiar...