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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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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35 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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45 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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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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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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65 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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42 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 ...
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1answer
85 views

Why does DMA send the first byte as soon as it is enabled?

I'm using DMA to send data to GPIOF which is configured as a parallel bus. DMA is being driven by update events on TIM8. TIM8 is configured in slave mode and starts on an output compare event from ...
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47 views

Interfacing DCMI with SDIO and FMC on STM32F446VE

I am attempting to implement a system which involves capturing 1080p images via a camera connected over 8 bit parallel DCMI and saving them to an SD card via SDIO. If I understand correctly I cannot ...
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80 views

STM32H7 - MDMA with DCMI

I am using DCMI peripheral on STM32H7 to capture an 320x240 monochrome image (1 byte per pixel) and DMA to transfer it to D1 SRAM. DMA uses FIFO, Threshold: Full, Data width: Word for both source and ...
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117 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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113 views

How does the DMA know “when to send” the next byte?

I'm transferring data from memory to a peripherial's register in an STM32 uC. For example take 20 bytes. I understand that after sending all the 20 bytes, the "Transfer Complete" interrupt will occur. ...
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24 views

MultiByte data integrity with DMA on STM32F3

Despite low-pass hardware filters on ADC inputs I am having a lot of erratic readings. There are 8 single-ended channels in DMA sequence and it is configured for cyclic sampling. Sampling time is set ...
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498 views

STM32H7 SPI DMA

On STM32H7 I'm using DMA for SPI transfer. I use SPI1 and SPI4, both in D2 domain, together ...
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505 views

Processing ADC conversion result: DMA vs Processor Registers

I have a periodic ADC conversion (every 50 micro-seconds) and I use the result to do some further calculations and update the PWM load registers. The ADC is triggered by the up-down counter of ...
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49 views

DMA and Instruction Pipeline

My university resources say that DMA transfers the bunch of data from IO unit to memory or vice verse when processor is not busy with data and address bus. According to the resources, DMA Controller ...
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2answers
1k views

How to configure DMA to receive variable length USART messages?

I am trying to receive USART messages on a microcontroller originating from PC which will command it to execute certain tests. I am using STM32F4, I chose to use DMA as messages on the same USART ...
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1answer
46 views

CS43L22 DMA constant beep noise

I am using CS43L22 with STM32F4 discovery board. I generate sounds by sending I2S messages to CS43L22 using circular DMA buffer (32 size array). However, chip creates a constant beep whether it's ...
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37 views

DMA Init code for ADC sampled data

I am trying to figure out how this DMA Initialization code is used to sample following 4 ADC channels and save data in 'adc_data'. ...
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209 views

STM32L4 ADC DMA only Triggers Once

for some reason my DMA only seems to update ADC values once. I've set it up so that the callback function simply raises a flag everytime the DMA converts the ADCs, this flag only seems to go off once. ...
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41 views

Custom PCIe DMA on Cyclone 10GX FPGA burst read stucks

I'm writing a custom DMA machine to read and write data to the host system from FPGA memory. I use the Altera PCIe IP core as end point device in Avalon-MM mode. BAR0 is set as 64bit bar, Avalon-MM ...
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116 views

STM32f7 ADC DMA transfer not populating the buffer

I'm trying to compute the FFT of a 100 kHz signal from the STM32f746G discovery board using the HAL and CMSIS DSP libraries and I've run into a few issues. My first issue was trying to trigger the ...
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67 views

Concurrent DMA streams handling UART

I've currently got a STM32F777VI microcontroller working with UART receive working through DMA. The problem starts when I try to receive data from 2 UART peripherals using DMA. According to the ...
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2answers
165 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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1answer
100 views

STM32L432 full duplex DMA SPI slave locks up after communication starts

I am continuously sending a substantial amount of data between the STM32L432 and a FPGA using SPI in full-duplex mode. I decided to implement DMA on the L432 in order to increase the transfer rate ...
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223 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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1answer
147 views

Why is DMA running continuously?

I'm facing a strange behaviour of DMA which I cannot explain myself. I just want DMA to send a data block (i.e. one 32bit word) to the SAI peripherie and quit then and give a "transfer complete ...
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495 views

STM32 HAL PWM output with DMA misbehavior

I use the Blue pill STM32F103C8T6 to generate variable duty cycle PWM with DMA and using HAL library. And stuck with undesired results. First, I generated code with STM32CubeMX v5.0.1, HAL v1.7.0, ...
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678 views

STM32 HAL UART receive timeout interrupt

I'm developing a software for the STM32l432KC (NUCLEO-L432KC) which uses 2 UARTS with DMA (RX DMA mode to DMA_CIRCULAR) using HAL. My problem seems to be quite common: the UART buffer length is ...
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108 views

STM32H7 DMA2D MEM2MEM rectangle coordinates

Question: how do I specify rectangle copy parameters of source (x1, x2, width, height) and destination (x2, y2) buffer using DMA2D registers, in memory to memory mode? My problem is that I cannot ...
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197 views

STM32F072 TIMER PWM + DMA : Not working as expected

I am using TIMER2 + CHANNEL 2 PWM to generate 800 Khz wave. The idea is to vary the duty cycle of this wave as per a statically generated pixel bit array (1 SK6812 pixel = 32 bit GRBW = 32 bytes of ...
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241 views

SPI using STM32's DMA sends one word too much

On an STM32F103 I configure SPI in 16bit wide mode and set up a DMA transfer to transmit one byte: ...
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1answer
68 views

Multi-tasking on an 8bit AVR -

I'm using an ATTINY816 (the new series AVRs) to manage a system that includes the following tasks: Simple audio "effect processing" (delay, pitch up, pitch down...) using internal ADC + DAC Storage ...
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1answer
479 views

STM32 cant get DMA on PWM

I wish to drive a set of NEOPIXELS (ws2812b) using the STM32F4 discovery board, so far i managed to get a 800 kHz PWM signal using the CubeMX. And And the following code: ...
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2answers
60 views

PIC32MZ, MPLAB Harmony with I2S hangs after adding extra function

I have referred http://microchipdeveloper.com/harmony:i2s-tutorial and am able to configure the I2S and read continuous data from a microphone. I am facing issue with the microphone data, and have ...
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2answers
1k 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
290 views

STM32f103 DMA with PWM repeating values

I have a Blue Pill (STM32F103) and connected to it a ws2812b led strip. I am trying to send data to the led strip via PWM over the TIM2 peripheral (Pin A0). To change the duty cycle of the TIM2 PWM I ...
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844 views

What do these arrows on a pinout represent?

What do these arrows represent? Is there any way to memorize it easily?
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1answer
196 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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1answer
1k views

TIM2 DMA configuration for stm32h7

My problem: I can't configure DMA to working properly on Input Capture event. Data doesn't transfered and error occurs. ...
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282 views

How to store DMA buffer array?

I am trying to store DMA buffer array such as below; ////////////////////Global Area;//////////////////////////////////////// ...
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694 views

STM32F7 + TI ADS127L01: SPI with DMA circular mode + Timer IC for data ready signal + CRC

I've connected a TI ADS127L01 to the SPI2 of a STM32F746 mcu via SPI2 and Timer 2 Channel 4 input capture for the data ready signal. As soon the data ready signal is captured, the SPI TX DMA (which is ...
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2answers
1k views

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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324 views

STM32 PWM generates excessive pulses

I use STM32F103C8T6 to drive WS2812 RGB LED strip. So I try to setup TIM1 to generate PWM using DMA. Everything works fine except the fact that I get more waves then I requested. Almost all the code I ...
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1answer
494 views

How to reconstruct input signal by using DAC?

I am working on a project in which - I have to continuously monitor the the ADC input on a microcontroller(STM32F407) and check if the value crosses a certain threshold. If the value crosses the ...
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1k views

STM32F7 Timer and DMA

I'm currently trying to adapt the example project TIM_DMA of the F769I_EVAL to the STM32F746G discovery board. I'm quite new to STM32 and this might be an obvious error. The code creates a timer and ...
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1answer
61 views

DMA transfert data

I have 2 image files imported by ENVI tool (png or raster file), and they are stored in my hard disk, I want to transfer this data from host PC to target FPGA using DMA (Data Memory Access). My ...
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245 views

Where is the location of display buffer on a computer board? [closed]

On an OS development text by Nick Blundel, at chapter 4.1 titled Adapting to Life Without BIOS, it is explained that while graphics hardware is in text-mode, we can write ASCII characters on screen by ...
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1k views

ADC DMA on STM32, Nucleo F334R8 stops main while loop from executing

I am am reading ADC via DMA on the STM32 Nucleo F334R8. However, after I start the DMA using the code below, the main while loop fails to execute ...
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41 views

STM32F10x DMA a constant value

does anyone know if it's possible to DMA a constant value using the STM32F103? I've scrutinized the datasheet but can't see anything obvious and nothing via Google either. Could do a single word in ...