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Unanswered Questions

235 questions with no upvoted or accepted answers
5 votes
0 answers
361 views

SPI between Master arduino and Slave arduino

How can I send the string from Slave SPI to Master SPI? I want to write code in Bare Metal. The problem which I am facing is I can't make out what will be my blocking function in Master SPI code when ...
3 votes
0 answers
381 views

Raspberry pi pico (Arduino core) not initialising SPI correctly for NRF24l01

I'm working on a project where i have a Raspberry pi Pico connected to a NRF24l01+ to send some data. However i'm not recieving any data on the reciever and i think that its because the SPI bus is not ...
3 votes
0 answers
191 views

Grove LCD display not working with arduino rev 2 wifi (Unknown error at address 0x3E)

I am trying to connect Grove 16x2 LCD (White on Blue) to my Arduino uno rev 2 wifi. So far, I've tried hd44780 library's ioClass examples, but nothing worked. I've then decided to scan ports and when ...
3 votes
0 answers
1k views

ESP32-C3 SPI Class documentation/features?

ESP32-C3 has a nice feature called GPIO Matrix which allows to map most of it's peripherals to any GPIO pin. And it has feature called IO_MUX which allows direct & faster operations for some of ...
3 votes
0 answers
204 views

Black screen when using higher SPI-speed for RA8857 LCD-controller

I'm using an Arduino Due that talks via SPI to an LCD (800x480) with the RA8875 controller chip. The most recent datasheet I could find is: RA8875 datasheet. Everything works as expected when using ...
3 votes
0 answers
793 views

SPI register read returns 0x00 or 0xff

I am trying to interface a Arduino Uno with an ASM330LHH using SPI. Whenever I try to read any register, I either get 0xff or 0x00 on the serial monitor The code I am using: #include <SPI.h> #...
3 votes
0 answers
2k views

How to use SPI to set/ read registers for a sensor (Avoiding need for Github Lib)

Ok so as some readers might have seen, my current project involves using MPU's. The idea is sending data via CAN bus to a controlling MCU to then send to a raspberry pi to perform the calculations ...
3 votes
0 answers
220 views

Scheduling and BLE Read on demand

I'm building a data logging device with BLE capability using RFduino. Sensors are read using timer interrupt to a buffer. When the buffer is full, then the whole buffer is written to SD card. At the ...
3 votes
0 answers
498 views

SPI communication between two Ethernet Shields (W5100)

I am a newbie to the world of IoT, I want to ask... Is it possible to connect two Ethernet shields with SPI? And if yes, how can I codes them? I have reference from http://www.gammon.com.au/spi and ...
3 votes
0 answers
601 views

Do software SPI read from a register using shiftin()

How to read from a register using software SPI, presumably shiftin()? It works using the builtin SPI library + hardware SPI. I seem to be able to write but not read using manual shiftin()/shiftout()...
3 votes
0 answers
700 views

Serial does not work when LiquidCrystal library is used

I have been struggling with a LCD for 6 hours straight - I've had many problems including random characters showing up, and this time (not quite sure what changed, I tried so many things) as soon as I ...
3 votes
0 answers
921 views

Read from the SD card - ACMD41 times out

I'm trying to read from the SD card using an Arduino Pro Mini (3.3 V), Pololu micro-SD reader (the 3.3V one) over a SPI protocol. I've tried both the SD library from Arduino SDK, and the Adafruit one....
3 votes
1 answer
1k views

3.5 inch TFT LCD connection diagram with mega r3

Forum post I would like to ask if someone has this shield fully working? My biggest problem is the touch screen that I couldn't manage to make work. Here is the code I am using: // ic: ili9327 #...
2 votes
1 answer
106 views

L9780 and SPI communication

I'm working on a program to interface with a development board I spun for an L9780 - wideband oxygen controller IC. At this point, I'm trying to get a consistent "status" read back but ...
2 votes
0 answers
103 views

Slow I2C communication

To collect temperature and BPM, I connected a max30101 in my Heltec WiFi kit V3 with ESP32. The data collected are stored in arrays to extract statistical features from signals which an algorithm will ...

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