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Unanswered Questions

329 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 ...
4 votes
0 answers
718 views

ArduinoDue - Matlab: SerialUSB.write() sends ASCII?

I'm trying to get some binary data from an Arduino Due to Matlab. Basically this is the setup: Due: byte usbMsg[33]= {0}; // filled with dummy as example usbMsg[1] = '00000001';// in[3]; usbMsg[2] =...
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
713 views

Getting atsam3x8e (Arduino Due) to work

I decided to make a pcb based on the atsam3x8e (microcontroller used in Arduino Due). For the design I copied most of the layout that I found on this site and looked at the official Arduino Due ...
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
1 answer
2k views

Creating a sine wave with a DAC and feeding it back

I want to produce a digital sine wave, send it to DAC0, and then receive it back as input on A0 and plot the graph. I am using an Arduino Due. I wrote the following code: #define maxSamplesNum 120 #...
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
378 views

Connecting Arduino Due's DAC output to pc sound card with protection

I would like to connect the DAC outputs of my arduino board to my pc sound card input so that I can use my sounds card as an osciloscope. I have two questions: 1- if I don't use an amplifier, how ...
3 votes
0 answers
129 views

Reading Reveive Hold Register from USART in SPI Mode on Arduino Due

Sending with this function here works fine: uint16_t usart0spiTransfer16(uint16_t spiMessage16) { uint16_t sdo = 0; byte firstByte = spiMessage16; byte secondByte = (spiMessage16 >> ...

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