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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16bit DMA UART w/ STM32F4

How do I transmit 16 bits of data with UART to a 16 bit array? I've got two elements in my array, my UART is set up as 8N1 and my DMA is set to circular. I'm using some HAL stuff, and here's my ...
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stm32 gpio to dma

I have a few questions regarding using the DMA of the stm32f7 board (nucleo F722ZE ). 1) So to get started I'll explain what I'm doing: I need to read data from 2 GPIO pins (ADC) and will have a ...
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1answer
4k views

STM32 HAL UART Transmit DMA problem

After setting up my project for a custom STM32F7 board which includes a FT2232H UART<->USB converter I got multiple problems when sending (and receiving data). The code I use is mostly generated by ...
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1answer
921 views

STM32F4 How to stop triple interleaved mode?

I am using triple interleaved mode with DMA in STM32F429 and have problem stopping it. It should be stopped by HAL_ADCEx_MultiModeStop_DMA(&hadc1), but while ...
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1answer
132 views

PCIe DMA transcation to multiple PC RAM slots from FPGA

An FPGA endpoint needs to needs to transfer large quantities of data to the host processor's RAM over DMA. So memory mapping to a single RAM might not be possible. Normally high end PCs or Servers ...
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953 views

4-bit parallel data bus using DMA and GPIO on STM32?

It's possible to generate 8 or 16-bit parallel output on an STM32 by using DMA to transfer from a buffer to the ODR register of a GPIO port, by transferring either a byte or a word at a time. However ...
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1answer
364 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
267 views

HOLD signal in 8085

What happens to an 8085 system if a square wave signal of 1KHz frequency is applied to the HOLD signal of 8085? The frequency of operation is 2MHz. Therefore, if the every 0.5ms, the HOLD pin goes ...
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1answer
506 views

DMA circular input

I want to copy the same value, say 0.0f, into a big block of SDRAM through DMA. For example, STM Discovery 429 uses DMA2D for fast screen clearing with the ...
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1answer
4k views

DMA triggered by Timer using STM32F4-Discovery board

I am trying to trigger the DMA peripheral by the Timer using STM32F4-Discovery board, but it doesn't seem to work. I want to get the value of a port (Port C) every 5 ms and save the value in memory ...
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2answers
403 views

What's the advantage of DMA in byte I/O?

I have a A/D where signals CPU(Analog Devices Blackfin 706) whenever it has new sample, and CPU reads that through a SPI, which is few bytes. Then waits for new smaple signal again. My question is, ...
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635 views

STM32 DMA short data burst buffer speed limitation

I had gone through few texts on this topic (listed below), but was not able to figure out the speed limitation of STM32´s DMA. What is needed: Take 8bit parallel burst input from external ADC (20 kB ...
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4k views

HAL + DMA + UART = STM32 crash

I'm currently working on a project which involves communication between a STM32F303RE (Nucleo board) and a classic GSM/GPS SIM808 module plus other peripherals. I want to use the DMA + UART of the ...
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350 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
1k views

STM32 SPI DMA timings between data frames and multiple DMA profiles

I'm trying to setup the STM32L432 MCU for SPI communication (24 MHz, 16 bit data size, master transmit only), using DMA. The slave device is a 32 channel amplifier chip. I need to send a specific ...
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2answers
12k views

STM32 DMA: continuous peripheral to memory (array) transfer

I am trying to use a DMA in circular mode to transfer data from an ADC to an array that will hold the data. I need to concurrently use the incoming data (in this case, I am using AT commands to send ...
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1answer
444 views

STM32F4 bugs in DMA, is there bug-free version?

Producer has confirmed that if there will be concurrent AHB and APB2 transfers using DMA2, then data corruption will occur (source). The bug discovery is from 2012, many years ago. Is the STM32F4 ...
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276 views

Vivado VDMA: How to use it?

I have my own IP block with 24 bits input/output axi stream type. It is an image processing ip. Thus, it should be connected by VDMA. I tried to configure VDMA accroding to the example and datasheet. ...
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3answers
9k views

STM32 HAL UART transmission

I'm trying to send data by STM32f103 to an Arduino board using UART. Data isn't received properly. The code is generated using STM32CUBEMX and here is the part I added: STM32 code (Transmit): ...
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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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2answers
2k views

STM32: avoiding DMA & CPU collisions

Section 13.4 of the STM32 Reference Manual (for my STM32F303RE board) states: The DMA controller performs direct memory transfer by sharing the system bus with the Cortex-M4 ® F core. The DMA ...
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2answers
5k views

STM32 SPI slave: Reset DMA state on high NSS

I'm trying to setup a STM32F303RE SPI2 slave that must continuously and repeatedly send contents of a 2-byte buffer using DMA. More specifically, if my buffer is: ...
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1answer
707 views

How to transfer data from/to the I2S controller through AXI DMA

I'm doing a sound analyzing project on the Zybo board and I'm having hard time using the AXI DMA for transferring data from the I2S controller to RAM. I'm using the I2S controller from the Digilent's ...
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1k views

How to properly send stop condition when using DMA with I2C?

I'm using DMA transfer to get 1024 bytes from master (STM32F407VG) to slave OLED screen (SSD1306). The library I'm using does this: ...
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1answer
570 views

Synchronize internal DAC to I2S on STM32F4

I have a CS4344 DAC connected to my STM32F407 outputting sound at a 44.1kHz rate with DMA and I2S and I would like to output and envelope signal through the internal DAC of the STM32F4, in sync with ...
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1answer
5k views

STM32 SRAM to DMA GPIO pins

I wish to transfer a large array of data to 8 output pins that are all on the same port. E.g. a 500 element 8bit array where each bit of each element represents the pin status. So 500 independent ...
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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
3k views

Can the STM32 DMA speed be controlled by the timer?

Is it possible to have the DMA controller on an STM32 transfer each packet only when a timer update event occurs or can you only control the start of a whole chunk of DMA? The use case is (on an ...
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0answers
887 views

STM32F401 SDIO with DMA

Please need help in: Do somebody have a a working code that writes to sd card via sdio using FatFs and DMA?( data logger) In a poling mode (without DMA) I am writing to .bin file and getting error ...
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1answer
2k views

STM32 : reset the I2S DMA address pointer

For my application I have a DAC communicating with an STM32F4 through I2S. On the microcontroller's side, informations are send to the DAC through a DMA stream, with a circular buffer. On an external ...
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1answer
2k views

Is the STM32 DMA destination address restricted?

I'm using a stm32f446 and would like to use the TIM4_CH2 request with the DMA1 in ...
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3answers
355 views

SPI between MCUs

As a newcomer to PIC programming, I am looking for some thoughts on how to implement SPI between a master and slave MCU the most efficient way. The purpose of this system is to provide an extremely ...
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1answer
1k views

Generating video with ZYNQ, using IP block design?

I am trying to implement a video streamer on Digilent ZYBO board that has Xilinx ZYNQ 7010. By the way, reason of this thing is to test the quality of an encoder board. What I want is to: Generate a ...
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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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1answer
1k views

stm32 f411re ADC + DMA

I would like to measure pin PC1 and compare it to Vref to get current voltage. This code below worked on L152re. I changed pin number, ADC1 address and DMA channel. It measures something but I am sure ...
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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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1answer
96 views

How i can store 64 byte data into flash faster as 1 ms?

I have one problem with store data into flash on my uC LPC1759. I need to save 64 byte data into flash, but when i use IAP-Interface, it takes more than 1 second. Is there a way to make it faster than ...
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5answers
5k views

Does a CPU completely freeze when using a DMA?

I have pretty straightforward question, but I couldn't find an answer to it anywhere. On a Von-Neumann system where code and data live in the same RAM, the CPU must fetch all its instructions from ...
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2answers
1k views

WS2812B 16 Channel Drive with STM32 problem

I am working with this library. This library uses DMA1 channel 2,5,7 but these channels are required by USART. So I have changed the channels and corresponding to timers ( totimer2 and to timer4). ...
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1answer
535 views

STM32 Timer Function Generator

I wonder how you can achieve that a GPIO pin accuratly toggles according to a certain pattern. This pattern is fully variable (no PWM) and is stored in memory. My conclusion of this is: The pin has ...
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1answer
531 views

How does Frequency-division multiplexing deals with overlaps?

As I understand it, FDM uses separate frequency for each channel, thus A will transmit data, for instance, every two seconds and B every three seconds. But, what will be delivered on the wire in the ...
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1answer
718 views

problem with dispic33 using DMA between UART and ADC

I'm using dsPIC33FJ128MC804, i intend to read from ADC and send to UART but via the DMA ( direct memory access ) which is supported in that MCU , i use Mplabx c16 there is a problem with my code i can'...
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4answers
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Method or function to determine if pointer is to address in flash or RAM?

I'm working with an ARM Cortex M4 microcontroller that has a DMA, or peripheral DMA controller. One requirement of the DMA is that it cannot access pointers to addresses that exist in flash, but only ...
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1answer
3k views

Restart Rx USART + DMA in STM32L1

I am using an STM32L1 on a Nucleo-L152RE board. I have to devices I control through serial running at rather high baudrates, so I am trying to enable DMA on the USART. With the code below I can launch ...
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1answer
660 views

msp430 DMA UART for Modbus

I am using MSP430 UART with DMA transfer for sending Modbus packets. As a master at the end of packer I need to change my RS 485 transceiver direction line for reception. I am sending 10 bytes in ...
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2answers
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STM32F3 Circular DMA

I'm having some trouble getting my memory to GPIO DMA circular settings right. The initialization code pasted below has some issues. I'm trying moving data from a uint16_t array to the GPIO->ODR ...
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1answer
3k views

Axi DMA correct parameters

I'm making my design with Vivado HLs and Vivado and I'm doing some somewhat big transfers between DDR and my custom IP block and vice-versa. Each transfer from DDR to custom IP is of 256x256x4=262144 ...
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0answers
410 views

Fly-by vs flow-through DMA

I know that fly by DMA controllers (such as Intel 8257) are basically rewiring the circuit and arbitrating the flow of data. On the other hand the flow through ones keep some of the data into its ...
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1answer
436 views

Zedboard 512x512 matrices, % utilization problem

My objective is to read seven 512X512 float matrices from the SD card to the DDR memory (step accomplished already with each matrix occupying around 1Mb), then pass them from DDR to my custom IP block ...