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Questions tagged [spi]

SPI is a low-level 3 or 4 wire serial bus interface with clock (SCLK), data in (MISO) and data out (MOSI). The fourth wire is a Slave Select to uniquely select a device on the bus. This signal is usually active-low. Slave Select, Chip Select, CS#, SS# stand for the same function, typically. Be sure to check the datasheet, though. The SPI bus is a *de facto* standard lacking the formal specification.

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Why does the SPI bus with 2 devices crash in this setup?

I am using Feather M4 express development board with DC Motor + Stepper FeatherWing and Ethernet FeatherWing stacked on it. The idea is to control the steps of the stepper motor by reading the encoder ...
dreamcoder's user avatar
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ATMEGA328P ISP SPI connection conflict issue

With reference to similar issue: SPI device prevents ISP programming I have 2 ATMEGA328Ps with MOSI MISO and SCK permanently connected on the same board. At the time of printing the board my thoughts ...
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Buffering Arduino SPI bus using 74AHCT125

My SPI bus has 2 slaves, one is 5V tolerant and is connected normally to the bus, however the second one is only 3V3 tolerant and so I have to level shift it. I have decided to use the 74AHCT125 ...
zoghii's user avatar
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SPI flash memory (AT26DF161A) with PIC16F883 write wrong data in memory and Manufacturer ID is wrong

I'm working on a product with a TFT display and I want to save the screens in a flash memory. I had available an AT26DF161A memory, so I build a prototype in order to test it with a PIC16F883. I wrote ...
Hernan Couto's user avatar
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How to isolate a chip from a board without unsoldering it?

I have a board from some device with SPI flash memory chip. I also have a separate CH341a programmer for such chips and I intend to read the SPI flash memory chip from the board. Now I want to do this ...
Arthur  Bulakaiev's user avatar
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Problem with SPI Communication - STM32 Nucleo U575ZI-Q/STEVAL-MKI168V1

I am currently learning by working on a project in which I have to establish a SPI communication between a Nucleo U575ZI-Q and a STEVAL-MKI168V1 (IIS2DH eval board). To set up the Nucleo board and its ...
Nasser Shehadeh's user avatar
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Problem with STM32MP1 SPI using DMA

When running some simple code to test the SPI communication using DMA, the program only works as expected after stopping and restarting the microcontroller. The first time it runs, instead of sending ...
Fábio Silva's user avatar
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SAMD51 SPI on SERCOM0 not working as expected

I'm trying to use a SAMD51G19 48 pin package to write a very simple SPI program, which will just loopback what's output back into the input, but I'm still new to this processor and haven't done SERCOM ...
daannn's user avatar
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EFT (IEC 61000-4-4:Burst Test) Fail. I used SPI Interface [closed]

I am using TI ADC part# ADS131E08 and STM MCU Part# STM32H7 Series. #3 channel : Voltage measurement (3phase) #3 channel : Current measurement (3phase) #1 chanel : Internal-zero current measurement. #...
DSKIM's user avatar
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SD card via SPI: any way of getting it out of stuck state after aborted SPI operation(s) without power cycling it?

using ESP32 and its IDF platform libraries to access SD card via SPI, we have a situation where e.g. panic reboot of ESP32 leaves the SD card 'stuck' such that it cannot be mounted any more after ...
tangram's user avatar
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SPI Mode Selection

Im trying to determine SPI mode of CS5364. Section 4.13.1 SPI Mode of the datasheet says: CDOUT is the output data line to a controller. Data is clocked in on the rising edge of CCLK and is supplied ...
Electronx's user avatar
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Question re: layout and grounding of a PCB with SPI-controlled H-bridges and load switches

My question is regarding the layout, and in particular the grounding, of a PCB that has a microcontroller that controls various H-bridge drivers (that will be PWM’d) and load switches via SPI. The ...
Mark512's user avatar
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3 answers
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SPI device stops working when integrating Schmitt triggers and ESD diodes

I am integrating a BME680 temperature, pressure and humidity sensor using SPI. When I only use 33 Ohms series resistors, the system works fine. However, when adding Schmitt triggers (NL27WZ17DFT2G), ...
Tommy95's user avatar
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MISO line on SPI appears as if it was discharging a capacitor

I was inspecting SPI lines on my PCB using an oscilloscope to see if there was a skew between SPI line signals or not. The SPI clock is running at around 4.5 MHz. CPOH= 1 and CPOL = 1. I got the ...
abdo Salm's user avatar
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MAX1415 ADC not reading voltages correctly. Incorrect setup procedure?

My device uses two of the MAX1415 dual-channel sigma-delta ADCs. I've labeled them "MADC" and "CADC" for "Measurement ADC" and "Calibration ADC". They are ...
AuFries's user avatar
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Why is the Clock Signal referred to as SCK instead of CLK in SPI?

I understand "SCK" expands to "Serial Clock", but simply calling it "Clock" would have worked just as fine. Am I right to understand that this "S" is a ...
Curious_Baby's user avatar
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ST7735 1.44" SPI TFT GreenTab: white lines/ghosting (no hardware fault!)

I have been using SPI-TFTs for a while now, usually the 1.8 inch 160x128 also with ST7735 controller. No problems. I bought multiple 1.44" ST7735 square 128x128 TFTs over the last year. Today I ...
sutt's user avatar
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2 answers
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SPI cable with twisted pairs with ground: Are ground loops an issue?

I am connecting my microprocessor to a SPI device through a cable, with the SCK, MOSI, SS and MISO lines, in addition to +3.3V. I was told it is advisable to twist each line cited above, including the ...
Tommy95's user avatar
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What is the appropriate VCC to apply to a Schmitt trigger?

I would like to transport a SPI signal over 1 meter, at a 10 MHz clock rate, with each SPI wire twisted with a ground wire, no differential signal, 33 Ohms terminations, ESD protection with chip ...
Tommy95's user avatar
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Can I turn off the transmitter when receiving half-duplex SPI?

I have a STM32F103 Blue Pill-based interface board which is being used to translate from USB to a custom single-wire debugger interface (used by some Telink chips). I didn't write it, but I'm trying ...
David Given's user avatar
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3 votes
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Why is a Schmitt trigger useful for SPI?

I understand Schmitt triggers are a great way to convert a floating or noisy signal to either HIGH or LOW depending on a threshold. It is mentioned in other threads that a Schmitt trigger can help ...
Tommy95's user avatar
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Discrepancy between SKR Mini E3V2 and documented SD Card Pinout

There is a schematic of the BTT SKR Mini E3 V2 available on the internet and I was taking a look at the SD Card Pinout. First of all I noticed, that it appears to run in SPI and not SD mode. Fine okay,...
HeartOfGermany's user avatar
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1 answer
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Interface micro SD card with MCU and USB port at the same time [closed]

I'm designing a PCB and I would like an MCU (ESP32-S3) to be able to write periodically on a micro SD card (logs). I'm using SPI. I also would like to be able to get those logs through a USB port on ...
AyubowanPro's user avatar
4 votes
3 answers
591 views

Custom Arduino MEGA crashes ONLY on a specific command when plugging UART-USB converter before main power. Phantom power leaking through UARTs pins

Disclaimer Based on multiple attempts to find the cause of the problem, I have determined that I might be facing a hardware issue rather than a programmatic failure, hence why I am posting this here ...
Daniel Melendrez's user avatar
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Can't enable W25Q for writing (using STM32F103)

I am trying to work with a W25Q128 and previous I got stuck with talking to the chip, but stackoverflow helped me and I was able to communicate with the chip. Now I am unable to bring the chip into ...
Rakesh Mehta's user avatar
1 vote
1 answer
94 views

What are some typical SPI NOR flash failure modes?

I am working with SPI connected NOR flash memory and I've noticed that something like 0.01% of devices experience some kind of write failure over their lifetime. We are careful not to exceed the ...
satur9nine's user avatar
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2 answers
66 views

Can't read data out of SPI device using STM32F1

I am new to STM32 family and trying to work with an SPI chip (W25Q). It seems like the micro is sending the desired bytes to W25Q, but the chip does not respond. Now I have a question with the CLK ...
Rakesh Mehta's user avatar
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STM32F103 SPI Clock Signal is not generated

I am trying to communicate with a Winbond W25Q (16 MBit) chip with Standard SPI connection. I am using Keil to code and debug. It looks like I am unable to generate the clock signal for the SPI line. ...
Rakesh Mehta's user avatar
1 vote
4 answers
123 views

What is the difference between the SPI master shorting MOSI and MISO and connecting an SPI slave?

According to the SPI protocol, communication must be between one master and one slave, but when I short-circuit MOSI and MISO, the SPI mater can also send and receive data normally. When I connect an ...
just a student's user avatar
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1 answer
68 views

Sending SPI Command for Two Devices on the Same Bus

I am working on a project where I may need to trigger two different DAC components at the same time if the timing for two simultaneous experiments line up. Originally, I was planning to use two ...
YashaSange's user avatar
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2 answers
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Interfacing Dual-Channel ADC with Arduino for Wireless Projects

I want to interface a dual-channel ADC (Analog Devices AD4632-16) with an Arduino that offers integrated wireless communication capabilities, such as Bluetooth, BLE, or Wi-Fi. I'm encountering a ...
Morena Fabozzi's user avatar
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Script Implementation of SN74HC165NSR

I have a PCB connected to my Raspberry Pi via its PiSound Header. It has 7 SN74HC165NSR shift registers. I'm trying to write a basic script that can read the ON / OFF state of the switches on the PCB ...
Jelani Thompson's user avatar
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2 answers
63 views

STM32F446 MCU SPI Problem with CC1120 Device

I'm currently working on a custom PCB with cc1120 datsheet as transceiver and stm32f446RET6 as MCU. I integrate the cc1120 library from IT's library. The device uses SPI as serial communication. Here ...
Burak Kayaalp's user avatar
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1 answer
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SPI register addressing scheme

I have been researching SPI communication protocol to do like a GUI interface for it. However, I came across a situation where it stated that the register address of the device where it has 8-bits, ...
Muhammad Rusydi Rasin's user avatar
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SPI communication, clock abnormal later than CS?

I use A40i and STM32 for SPI communication. A40i is an ARMv7 architecture processor, running on a Linux system in my environment. A40i is the SPI host and STM32 is the SPI slave. For the sake of ...
just a student's user avatar
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What is the best way to understand if nRF24L01+ still works properly?

I continuously transmit some data from one nRF24L01+ (nRF) to another one. After a long transmission time, I often experience that the transmitter stops its transmission at a random time for no reason....
adba's user avatar
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1 answer
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Connect ADS1298 to PC via USB

I designed an ECG board based on ADS1298 and schematics in this document (pages 52, 53, 55) with some customizations. I should connect it to PC via USB. As I found here, TI evaluation board uses a DSP ...
AmirSina Mashayekh's user avatar
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1 answer
158 views

Which pins are used for I2C and SPI in ESP32-S3?

I am using ESP32-S3-WROOM-1-N16R2 Controller in my design. I want to connect Sensor with this module which has both I2C and SPI Communication pins. I gone through the datasheet for controller, but i ...
Kuralmozhi's user avatar
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1 answer
81 views

Excessive use of vias

I am designing a four-layer board, with the layers as follows: Signal - Ground - Power - Signal. The microcontroller I will be using is an ESP32-S3, which I believe delivers an SPI-frequency of 80 MHz....
Timothy Nguyen's user avatar
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How to reduce on-resistance and parasitic capacitance effects of my MUX setup?

I am designing a mux board to mux a flashing setup. Both UART and SPI lines are on 1.8V logic. The Mux chips have ~4-8ohms on-resistance and 1.7pF on-capacitance. Few questions: Would I need buffers ...
Zed Lepplin's user avatar
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1 answer
56 views

Is there any way to get a smaller SPI clock speed specifically to only one SPI slave?

I have 3 modules connected by SPI through an ATMEGA328P MCU as shown in the circuit and I have some doubts over the clock speed of the bus. I have a 8Mhz clock on the MCU which I am assuming sets the ...
zoghii's user avatar
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1 vote
2 answers
117 views

SPI goes low too fast; Raspberry Pi Pico PIO and ADS7042

I am trying to use an ADS7042 (12-bit ADC) with my Raspberry Pi Pico with the Pico's PIO, but the signal goes low too fast and it seems to have problems going high sometimes, do I need to add some ...
Lucas Rønne Jeppesen's user avatar
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Interfacing ADC12138 with Digital Discovery using SPI

I am trying to interface ADC12138 ADC over SPI channel to Digital Discovery to read the single ended analog voltage in the rang of 0-4V on channel 2. As described in datasheet section 1.0 Snapshot ...
Ronnie's user avatar
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TM4C123 SPI slave reads only one byte

I'm sending the following sequence to an SPI slave in a Tiva TM4C123GXL board: I have captured this directly from the MCU pins. Notice SCK is running at ~190 kHz (pretty slow). The problem is that my ...
Dan's user avatar
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SPI: Write to display while reading multiple blocks from SD card

I'm reading BMP images with hundreds of kB's raw from an SD card and parse/write the image data to a TFT LCD with an AVR MCU with 2kB RAM. Reading a single block of 512 bytes with CMD17, passing it to ...
Torsten Römer's user avatar
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2 answers
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Multiple Page Write of Flash

My querry is, I am trying to write data from a file stored in by Raspberry PI to an external flash. The size of the file is greater than 256 bytes. As Flash allows writing a max of only 256 bytes in 1 ...
AD97's user avatar
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1 answer
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How to correctly shift the wipers of MCP4331 per SPI?

I am using an STM32 F401RE to control a Quad 7-bit digital potentiometer MCP 4331 using SPI Mode 0,0 protocol. You can find the datasheet Here. I can see that the microcontroller sends the correct ...
robotter's user avatar
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1 answer
102 views

Why is MOSI pulled low during communication?

I am using Allwinner A40i (ARM V7) as SPI master and STM32 as SPI slave. When not communicating with STM32 for SPI, it is correct to use an oscilloscope to capture ...
just a student's user avatar
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Frequency limit for routing <32MHz digital signals adjacent to one another on different layers, 4 layer PCB

I'm running an 3.3V SPI device with an SPI clock frequency rated up to 10 MHz, with some additional digital outputs/inputs to/from a microcontroller that is clocked at 32 MHz. Due to some space ...
plu's user avatar
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2 answers
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When using SPI interfaced SD Card Reader with MCU, the MCU is the master, right?

Hopefully this is a yes / no question. I just want to verify that when I'm using a simple MCU with a simple SPI interfaced SD card reader and writer, the MCU is in master mode and the SD card reader / ...
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