Questions tagged [dma]

Direct memory access (DMA) is a feature of computerized systems that allows certain hardware subsystems to access main system memory independently of the central processing unit (CPU).

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44 views

Recieving and processsing array of data on STM32

I am trying to use RealTerm to send a .txt file containing a 10X10 array of data to my STM32 NUCLEO board using UART. So far I have been using HAL_UART_Receive_DMA and I have been able to store simple ...
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19 views

STM32F4 Discovery ADC trigger using Timer 2 and DMA | CMSIS Core

I am working with a very old problem which is to convert ADC and send to UART via DMA. I am stuck at making the correct sampling time. What I had done so far is to configure TIMER2 and ADC. I Used ...
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40 views

How does cache coherency and DMA work together?

I am currently reading about caches and how they are used in Computer Science. The explanation of how the cache is always up to date with the actual memory is understandable as long writing and ...
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36 views

DMA + ADC + FreeRTOS in STM32 - Cannot read any ADC value - Why?

I'm using Nucleo STM32F401RE board. I have a small issue. I have connected SPI connections + two potentiometers and FreeRTOS. But I can't read the ADCs. I wonder why? I have created an array called <...
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1answer
43 views

STM32G474 signal generation with DMA + DAC using STM32CubeMX HAL

I am trying to generate a periodic signal with the DAC on the STM32G474 using DMA. There are tons of examples of this, and I´ve done the same in the past with an STM32L4 and F4 with no issues. However,...
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358 views

Garbage in SPI RX Buffer with DMA (STM32)

MCU: STM32f030f4p6 There is garbage in reception buffer, when I use SPI and 2 DMAs (for reception and transmission). ...
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58 views

DMA SPI performance

I am currently writing an SD card driver for a Microcontroller using SPI and DMA. The SPI has a FIFO that can store 4 data values from the data register which has the capable of storing 32 bit. But it ...
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1answer
259 views

Does not trigger an interrupt DMA when reading SPI. Last byte transaction not coming

I use DMA for reading with SPI flash using USART. MCU - master, flash - slave. I read 1029 bytes per transaction. Exchange algorithm: I activate the flash (CS = 0) I configure the DMA channel to ...
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2answers
72 views

STM32F051 ADC DMA overrun

I am trying to use ADC with 2 channels and DMA, but I only get 1 reading before the overrun bit gets set. Also the 1 reading is wrong, I am expecting a value of approx 2100, but I am getting around 70....
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353 views

DMA, Interrupt and UART connection in STM32 for detecting chararcters

I am trying to make a project and am planning to use DMA for my UART from one STM32 to another STM32. Here are some details of what am I using: Chip: STM32F107RB debugger and programmer: Atollic for ...
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43 views

DMA Continuous Request functionality

What is the difference between these features on STM32G0 "Scan Conversion mode" and "Continuous conversion mode" and "DMA continuous request" features? When you go on CubeIDE you will see these ...
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1answer
66 views

1V on ADC pin with DMA continuous requests

I have a STM32G071 Nucleo Board and also the IC itself. In CubeIDE, I set a pin as ADC and activate DMA and enable the DMA continuous request in the ADC settings. After executing the code and ...
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1answer
308 views

STM32F303 ADC+DMA Averaging of measurements

What is the best method of taking multiple measurements using ADC+DMA interrupts and averaging them? Currently I have an STM32F303 with ADC2 initialized with channels 3 and 18 (Vrefint). My aim is to ...
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60 views

UART Reception + DMA

When I am learning about DMA, I came to know that it can be implemented in UART peripheral operations too. Till now, I have used UART peripheral for simple communication operations. Sometimes I use it ...
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1answer
26 views

Decoupling setting of specific bits (transfer mode, stream, channel) from the generic DMA_Init() function

So with regards to DMA drivers, what's the approach for configuring certain bits generic inside a function which could be reused for both TX and RX calls which would require different stream parameter ...
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47 views

9*Help debug DMA TX bytes to UART

So I'm writing drivers for DMA for transmission for now and running into a few issues. So I am transferring bytes from memory to UART peripheral with a threshold of ...
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1answer
82 views

STM32 Spi receive problem

I'm trying to do simple SPI communication on STM32 Discovery, HAL lib is used. I'm trying to send some data via SPI1 and to receive same data on SPI3 (SPI1 = Full Duplex Master, SPI3 = Full Duplex ...
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69 views

How to access the other half of the DMA?

I am just trying to access the second half of the DMA. I have the half complete flag enable and working, however I am not entirely sure how to access the second half of the buffer. What I thought ...
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32 views

UART DMA RX buffer queue are being shifted on every power on- off

There is a communication between TFT NX8048p070-011r and my STM3F4 over UART. TFT sends 8byte data continuously and MCU receives by using circular DMA. I apply a parser to those data in Txclptcallback....
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2k views

STM32 ADC+DMA occurring only once

I'm trying to poll the value of the ADC and store it in a variable using DMA but the variable store the value of the ADC1->DR only once(when the program start). ...
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1answer
476 views

Microchip PIC24's DMA doesn't work as expected

I am trying to configure the DMA in Microchip's PIC24FJ1024, DMA channel will transfer Data, from Source to Destination, every time the program trigger the DMA Channel. One Shot Mode SRC increments ...
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1answer
43 views

Single Channel ADC with DMA giving garbage results on STM32F7

I'm looking to implement ADC and DMA with HAL on a F767. I want the ADC to be always converting and storing to memory via DMA until it reaches the buffer limit of 320 and then I want to go to a ...
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2answers
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Configuring the DMA request multiplexer on a STM32H7 MCU

I have recently switched to the newly-produced SM32H7 MCUs and I am currently in the process of migrating some of my old code to them (I want to see how they handle some applications that require a ...
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38 views

STM32 DMA BUFFER USAGE

I am using DMA for ADC and UART on my project and ADC has higher priority than USART. The ADC handles joystick and the UART handles keyboard. The ADC has 2 byte buffer and the USART has one byte ...
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108 views

AXI STREAM FIFO VHDL Implementation

Is this a right implementation of an axi stream fifo? ...
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25 views

I2S DMA interrupt gets fired but no data is available

I'm trying to read the I2S stream between a Raspberry Pi and a Hifiberry DAC with a STM32G071 and was able to implement the I2S DMA with the associated interrupt (or at least I think so). But ...
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54 views

Capture GPIO pin values with STMA32 and DMA

I am trying to capture all GPIO_C port pin values at a time when PA0 pin goes low. I am using STM32F091RC micro-controller. But I cant figure out why ...
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21 views

ADC / DMA only triggers once before setting OVR high STM32F446

I am trying to poll a block of sensors and load the data into an array via the DMA but the ADC polls only the first pin and then stops polling and sets the overrun flag high. I have implemented all ...
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29 views

STM32 ADC read temperature channel rarely between timer triggered conversions of regular channel

I am using a timer to trigger conversions of the ADC. The DMA writes the conversion results to a buffer of 512 uint16_t. When the buffer is full, an interrupt is triggered and I restart the conversion ...
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40 views

How do CPU, IOMMU and DMA controller interact with each other?

While drawing an interaction diagram involving CPU, IOMMU and DMA controller, I failed to find any authentic document showing how they interact with each other. Is the DMA controller physically a ...
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1answer
514 views

Why is DMA Continuous Requests not selectable as enable for STM32F446RE?

I have an Nucleo STM32F446RE and I'm used to enable DMA Continuous Requests with ADC. But in this case, I can only select disable. Why? If it's not possible to use DMA Continuous Requests with ADC. ...
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445 views

Using Character Match functionality in a STM32F7 chip

I'm trying to implement a UART receiver that works by finding a '\0' in the datastream, OR when it receives 256 characters at which point the data should be processed by an interrupt. The point is to ...
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177 views

STM32 ADC over DMA Continuous Mode Too Greedy

I am trying to read ADC data via DMA on an STM32F412. The reading itself works fine but the rest of the program is not executed anymore so it's killed by the watchdog soon. I have an array of size 50 ...
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110 views

stm32f1xx how to use DMA to write to TIMx CCR

I am trying to control WS2812b digital LEDs with stm32f103. I have a buffer of color values for the LED strip and to transfer them I need to write the next value to the timer's CCR every time the ...
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71 views

STM DMA won't continuously transmit on UART line

I am using an STM32L4R5 board and am trying to configure the DMA on the UART2 line. I have managed to get the RX line to operate how I want, but when I follow "Transmission Using DMA" in section 44.5....
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26 views

Sending Out Incoming SPI Data Through UART- PICMX250128B

I am trying to send out data(via UART) I receive from a 24-bit external ADC chip(via SPI), the ADC notifies the PIC 32 when data is ready so I am using an external interrupt handler(EXT INT). The ADC (...
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1answer
387 views

stm32 which timer and DMA channel should I use?

I am trying to control two lines of digital LEDs (WS2812b) with my STM32F103 using Timers with DMA and PWM. LED strips data lines are connected to PB5 and ...
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1answer
221 views

STM32F103 ADC via DMA - sequence scan to RAM can't make it work as expected

I'm using an STM32F103C8T6 BluePill board and CubeMX generated init code (Low-level libs) to setup the ADC + DMA to sequentially scan though 8 channels and write to an array in RAM. However, it either ...
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2answers
385 views

How to invert PWM signal on STM32

I am trying to control a WS2812 LED with STM32F103. The LED is a digital RGB LED also known as Neopixel. They are controlled by sending 24 bits of color data per LED to the first LED's data pin. The ...
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1answer
98 views

STM32 UART: combining interrupt and DMA modes

I am trying to use UART3 of STM32F103K8 to rx data in interrupt mode and tx in DMA mode. Reception works well, but transmission ...
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1answer
84 views

STM32F407 Discovery Board DCMI to SPI Output [closed]

I am currently attempting to use a STM32F407 Discovery board to display images captured with a OV2640 CMOS detector on a ILI9341 2.2" TFT SPI LCD. My goal right now is to take a single snapshot and ...
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1answer
70 views

Memory Boundaries in SRAM

I am trying to use the GPDMA which is present in LPC43XX parts. The UM10503 data sheet constantly warns about memory boundaries (datasheet section 21): basically it says that you don't want to try a ...
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1answer
49 views

M2P DMA transfer with trigger from a different peripheral

The microcontroller on my board is STM32F429IGT6 and I want to use a timer as a trigger of a DMA -e.g. HTIM_SOUND_SAMPLER- and transfer my data from an array to CCP of another timer -e.g. ...
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76 views

Multi-channels DMA Subsystem for PCI Express

Say i have a PCIe Gen2 x4 link running in a DMA subsystem. May I know when do we need multi-channels DMA configuration? For example, FPGA vendor like Xilinx offer up to 4-read & 4-write data ...
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3k views

STM32F - how to config DMA transfer to SPI triggered by Timer?

I am trying to make a project with the STM32F746ZG Nucleo board using the DMA to make a transfer of 16-bit values to a DAC connected to the MCU by SPI. I am using the STM32CubeMX to generate the init ...
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1answer
403 views

Stm32F103 DMA TIM1 - Load 50% of period.

I wrote a code using DMA with TIM1. In DMA buffer i load diffrent periods and send to ARR Register. How Can I change a Pulse of PWM to 50% from Dma buffer ? ...
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AXI4-Stream TVALID stuck low between VDMA and video output block

I'm trying to buffer a single frame of video using a VDMA block on a Trenz TE0712 board (artix-7 based development board), based on a few examples (specifically Numato's framebuffer example and Xilinx'...
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204 views

STM32 - 2 MegaByte DMA Transfer ADC To SDRAM

I want to transfer 2 MB of converted ADC data into SDRAM. I'm using STM32F429 Discovery board which is shipped with a 4-bank SDRAM (1 Meg Bits x 16 Bits x 4 Banks (64-MBIT)). I've configured the ADC ...
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1answer
184 views

Atmel SAMD21 DMA Transfer Complete Interrupt not firing

I have configured the SAMD21 peripherals so that incoming audio data from I2S will be copied into a memory buffer with DMA. As the controller allows linked DMA descriptors, I have two descriptors ...