Memory -> DMA -> UART

Altera_Forum · ‎03-24-2005

Quartus 4.2 | NIOSII 1.1 | EP1S25 DSP-Board | Win2k

Hi there,

i got the DMA working with HAL to send data from memory to memory. My next wish is to send data from memory to the UART. My UART receives 8bit, so i just tried to send one byte but it makes me a headache http://forum.niosforum.com/work2/style_emoticons/<#EMO_DIR#>/blink.gif Why can´t i just set the destinationadress to the UART instead of another part of the memory?

Has anyone experience with that? Do i have to implement a kind of sleep-function while sending data because of the lowspeed of the UART(9600bps)?

Some ideas would be nice!

Happy easter & nice egg-searching!

Altera_Forum · ‎03-29-2005

int fdterm; // FILEDESCRIPTOR RETURNED BY OPEN

int i; // for for();

FILE * fpterm; // FILE pointer returned by fdopen

int uart1_rxcount = 0; //counts received data from uart

alt_u8 uart1_rxbuffer[5]; //stores received data from uart

int pattern=0xF;//data to fill memory

unsigned int *p = (unsigned int*)(0x00010000);//Startadress

unsigned int *j = (unsigned int*)(0x00010100);//Destinationadress

//DMA_BASE= 0x00020880 //UART_BASE = 0x00020820

int main(void)

{

//Write to memory something

for (i=0; i<5; i++)

{

IOWR_32DIRECT(p/*+i*/, 0, pattern);//writes pattern from memory to memory+5

}

//to open the uart-channel in read/write-modus

// fdterm = open("/dev/uart1", O_RDWR | O_NONBLOCK | O_NOCTTY);

// fpterm = fdopen(fdterm,"rw+");

// fprintf(fpterm,"UART1 STARTED\r\n"); // check initial output

//printf("JTAG STARTED\r\n");

IOWR_ALTERA_AVALON_DMA_CONTROL(DMA_BASE, 0x0); // dma transfer disabled

//Send some words

IOWR_ALTERA_AVALON_DMA_STATUS(DMA_BASE, 0);

IOWR_ALTERA_AVALON_DMA_RADDRESS(DMA_BASE, (int)p); //Pointer to memory

IOWR_ALTERA_AVALON_DMA_WADDRESS(DMA_BASE, (int)j); //Pointer to your device

IOWR_ALTERA_AVALON_DMA_LENGTH(DMA_BASE, 4); //Sending words (1 word == 4 bytes)

IOWR_ALTERA_AVALON_DMA_CONTROL(DMA_BASE, 0x0CC); //See description of dma control register

return 0;

}

This is the code which copies from p (memory) to j(memory). Why can´t i copy from p(memory) to j(uart)?

I hope there is no huge thinking mistake http://forum.niosforum.com/work2/style_emoticons/<#EMO_DIR#>/sad.gif

thanks for help!

Altera_Forum · ‎03-30-2005

According to the views, my problem seems to be too difficult or too easy...

Altera_Forum · ‎03-31-2005

Have you tried setting the WCON bit in the control register? The RCON and WCON bits in the DMA control register are for when you have constant read/write addresses. In your case, you have a constant write address: txdata of the UART.

I would also set the DMA to perform byte transfers only, but that's just me...

Best of luck and I hope this helps!

- slacker

Altera_Forum · ‎04-01-2005

thanks for your answer, i´m on it...

i´m also trying to use the small-driver-option for the preprocessor...

the mode for the DMA was just a test, originally it was set on byte-transfer-only...

Regards, Max