Compiler/CC2541: CC2451 Is there a possibility in dma?

Alex Davidov

Part Number: CC2541

Tool/software: TI C/C++ Compiler

I want on interrupt timer do copy shift in dma
In result i want for every next interrupt get one single byte from data in dest

for example
on first interrupt
dist = 0x01;
on second
dest = 0x02;
etc...

I know that possible, if define dest as array like

static uint8 dest[1];

and in dest[0] reach wanted.

But need copy to dest as single byte

There is possible?

define LEN = 3;
static uint16 data[LEN] = {0x01,0x02,0x03};
static uint8 dest;

dmaConfig0.SRCADDRH  = ((uint16)data >> 8) & 0x00FF;
dmaConfig0.SRCADDRL  = (uint16)data & 0x00FF;
dmaConfig0.DESTADDRH = ((uint16)dest >> 8) & 0x00FF;
dmaConfig0.DESTADDRL = (uint16)dest & 0x00FF;
dmaConfig0.VLEN      = DMA_VLEN_1_P_VALOFFIRST;
dmaConfig0.LENH      = (NO_SAMPLES >> 8) & 0x00FF;
dmaConfig0.LENL      = NO_SAMPLES & 0x00FF;
dmaConfig0.WORDSIZE  = DMA_WORDSIZE_BYTE;
dmaConfig0.TMODE     = DMA_TMODE_SINGLE;
dmaConfig0.TRIG      = DMA_TRIG_T4_CH1;
dmaConfig0.SRCINC    = DMA_SRCINC_1;
dmaConfig0.DESTINC   = DMA_DESTINC_0;
dmaConfig0.IRQMASK   = DMA_IRQMASK_ENABLE;
dmaConfig0.M8        = DMA_M8_USE_8_BITS;
dmaConfig0.PRIORITY  = DMA_PRI_HIGH;

DMA0CFGH = ((uint16)&dmaConfig0 >> 8) & 0x00FF;
DMA0CFGL = (uint16)&dmaConfig0 & 0x00FF;

over 6 years ago

0 YiKai Chen over 6 years ago

Guru 735685 points

DMA is usually for large data movement. There is no need to use DMA for your application if you only need to get one single bit from data in dest.

0 Alex Davidov over 6 years ago in reply to YiKai Chen

Prodigy 40 points

Hi, thanks.
I have mistake on top post need a single byte not bit.
My question is about possibility do that in dma.
I have problem with do that in scope, when i try set it in interrupt timer, timer overflow more 3 time on out pwm i see 3 broken loops. I whant do that in dma without cpu.

0 YiKai Chen over 6 years ago in reply to Alex Davidov

Guru 735685 points

I couldn't understand your question.

0 Tim C over 6 years ago in reply to YiKai Chen

TI__Mastermind 34660 points

I also can not understand this question.

Regardless, it does not make sense to use DMA to transfer one byte of data. It is more efficient to just do this by standard variable reassignment / memory copy.

0 Alex Davidov over 6 years ago in reply to Tim C

Prodigy 40 points

Hi, look at my related question, can something help to understand.
e2e.ti.com/.../2774918

0 Tim C over 6 years ago in reply to Alex Davidov

TI__Mastermind 34660 points

It appears that the question you linked to is resolved. Were you able to follow the response from that thread successfully?

Also please post more information about the following: "I have problem with do that in scope, when i try set it in interrupt timer, timer overflow more 3 time on out pwm i see 3 broken loops. I want do that in dma without cpu."

What is a broken loop?

0 Tim C over 6 years ago in reply to Tim C

TI__Mastermind 34660 points

Is there any update here?

0 Tim C over 6 years ago in reply to Tim C

TI__Mastermind 34660 points

Closing due to inactivity.

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Compiler/CC2541: CC2451 Is there a possibility in dma?