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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173 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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28 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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1answer
171 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
122 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
50 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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2answers
100 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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256 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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1answer
1k 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
23 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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238 views

Setting up T2080 to FPGA PCie DMA

I'm doing an FPGA design using a T2080 MPC interfacing to an Altera Cyclone V FPGA. The goal is to use my FPGA to pump 2 other FPGAs on the same board. I need to create a scheme that allows the ...
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5answers
484 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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1answer
302 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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38 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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1answer
363 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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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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2answers
530 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
33 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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1answer
36 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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122 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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38 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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3answers
3k views

STM32 DMA Transfer bridge between 2 uart ports

I am using a stm32f103 and I'm trying to simply transmit all data received on 1 uart to another uart and vice versa. When using 2 terminal programs it works great, everything I type gets transmitted ...
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0answers
73 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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40 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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1answer
78 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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1answer
99 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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292 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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522 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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75 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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1answer
64 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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2answers
155 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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0answers
131 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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1answer
958 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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1answer
749 views

STM32F401RE SPI DMA flash driver read/write not working

I am facing problem with STM32F401RE with SPI flash driver. I am able to do normal SPI operations like read,write etc... But I need to use DMA to read and write to FLASH. /*****************************...
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7answers
10k views

What's the point of DMA in embedded CPU's?

I was doing a project recently with the mbed (LPC1768), using the DAC to output various waves. I read parts of the datasheet, and it talked about how it had DMA for a lot of the peripherals. This ...
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1answer
3k views

Nucleo F401RE ADC sampling Time

I would like to know how many samples I have per second for the ADC and what is its maximum samples per second and can I achieve a sample per 1 µs? Clock : 84 Mhz The board is Nucleo F401RE Here ...
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1answer
321 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
52 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
272 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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1answer
835 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
349 views

PWM over DMA on STM32F100 behaves strange

I try to drive WS2812B LEDs with the STM32F100 chip. I read a lot of sources and stopped on the following thing. I have a repository with latest version of code: https://bitbucket.org/ruslanpopov/...
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1answer
6k views

DMA between GPIO and SRAM on STM32

Here I am trying to move the data at the SRAM location 0x20000010 into the ODR register of ...
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0answers
375 views

Changing PWMs parameters on STM32 board

I am trying to change the values of Prescaler, Autoreload and Pulse of PWM using Serial communication on a stm32 Nucleo-F091RC. For the most part I am able to do so since the below code works fine: ...
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0answers
262 views

How to store DMA buffer array?

I am trying to store DMA buffer array such as below; ////////////////////Global Area;//////////////////////////////////////// ...
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0answers
609 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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0answers
271 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
430 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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1answer
613 views

SPI loopback with DMA

I am using STM32F4 discovery board and I am attempting to get SPI loopback with DMA. I have successfully got an "SPI-only" loopback running, but now I want use DMA in addition with the SPI, here are ...
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0answers
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
2k views

STM32 HAL Using ADC with DMA affects UART transmission

I am using STM32 Nucleo F334R8 board. I transmit some data using UART in asynchronous mode to my PC using: ...