Problem with DMA and UART Tx (MCF52233EVB)

Gonza — Fri, 27 Aug 2010 06:36:53 GMT

Hello!

I'm using the MCF52233 evaluation board and i'm trying to use the TX of UART0 with the DMA0. After setting the registers values, i begin the DMA, but nothing is sended and I get the Error 0x11 in the MCF5282_DMA0_DSR register (bus error on Destination ). I saw for other posts in the forum but i didn´t find a solution. First i thought that the problem was the DMA, and tested it doing a memcopy, so the problem is between the UART and the DMA.

Thank you very much in advance for any help.

Gonzalo

PS: Sorry for my english Here is the main code

#include "support_common.h"

#define N 200 // Bytes to Transfer

uint32 status; // For Debug

static unsigned char Source[N]; // Buffer

void main(void){

int i;

unsigned long int BaudRate=115200;

uint16 ubgs= (uint16)((60000 * 1000)/(BaudRate * 32));

//-------INIT BUFFER

for (i=0;i < N ; i++ ) Source[i]=65; //Fill buffer with A

//------INIT UART 0

MCF_GPIO_PUAPAR =MCF_GPIO_PUAPAR_URXD0_URXD0 //Enable RX pin

| MCF_GPIO_PUAPAR_UTXD0_UTXD0; //Enable TX pin

MCF_UART_UCR(0) = MCF_UART_UCR_RESET_TX; //Reset Transmiter

MCF_UART_UCR(0) = MCF_UART_UCR_RESET_RX; //Reset Receiver

MCF_UART_UCR(0) = MCF_UART_UCR_RESET_MR; //Reset Mode Register

MCF_UART_UMR(0) = MCF_UART_UMR_PM_NONE //Parity None

| MCF_UART_UMR_BC_8; // 8 bits

MCF_UART_UMR(0) = MCF_UART_UMR_CM_NORMAL // Mode: Normal normal

| MCF_UART_UMR_SB_STOP_BITS_1; // 1 stopbit

MCF_UART_UMR(0) = MCF_UART_UMR_SB(0x7); // Stop bit length = 1.000

MCF_UART_UCSR(0)= MCF_UART_UCSR_TCS_SYS_CLK; //Tx system clock

//BAUD RATE

MCF_UART_UBG1(0) = (uint8)((ubgs & 0xFF00) >> 8);

MCF_UART_UBG2(0) = (uint8)(ubgs & 0x00FF);

MCF_UART_UCR(0) = MCF_UART_UCR_TX_ENABLED; //Enable Tx

//-------INIT DMA0

MCF_SCM_DMAREQC=0x0000000C; //Uart0 Tx to DMA0

MCF_SCM_MPR |= 0x04; //Enable DMA access

MCF_SCM_GPACR0 |= 0x06; //read,write

MCF_SCM_GPACR1 |= 0x06; //read,write

MCF_SCM_PACR1 |= 0x06; //read, write for DMA

MCF_SCM_PACR2 |= 0x60; //read, write for UART0

MCF_SCM_RAMBAR |= MCF_SCM_RAMBAR_BDE; //Back door enable

MCF_DMA0_SAR = (volatile unsigned long) &Source[0]; //Set source

MCF_DMA0_DAR =MCF_UART0_UTB; //Set destination

MCF_DMA0_BCR = N; //Set de number of bits

MCF_DMA0_DCR= MCF_DMA_DCR_EEXT | // External request On

MCF_DMA_DCR_CS | // Cycle Steal On

MCF_DMA_DCR_SINC | // Source Inc on

MCF_DMA_DCR_SSIZE(0x01) | // Source Size= 1 byte

MCF_DMA_DCR_DSIZE(0x01) ; // Dest Size=1 byte

//----Start DMA

MCF_DMA0_DCR |=MCF_DMA_DCR_START;

while (MCF_DMA0_BCR & 0x02000000) {} // wait until dma finish

status= MCF_DMA0_DSR;

for( ; ; ) {} // do nothing

}

Re: Problem with DMA and UART Tx (MCF52233EVB)

mjbcswitzerland — Fri, 27 Aug 2010 20:08:17 GMT

Check that you have given peripherals the rights to access SRAM.

GPACR0 = SUP_USER_FULL_ACCESS; // enable peripheral SRAM access

This is not needed by memcpy() type DMA, which needs just DMA permission plus the back-door address (when from/to FLASH).

Regards

Mark

www.uTasker.com

UART User's Guide

Re: Problem with DMA and UART Tx (MCF52233EVB)

Gonza — Fri, 27 Aug 2010 22:11:05 GMT

First of all, thanks for your answer. I check this and I think is all right. the value of SUP_USER_FULL_ACCESS is 0x04 or 0x06 (this is from datasheet). So the code of the dma is:

MCF_SCM_DMAREQC=0x0000000C;

MCF_SCM_MPR |= 0x04;

MCF_SCM_PACR1 = 0x06; //read, write for DMA

MCF_SCM_PACR2 = 0x60; //read, write for UART0

MCF_SCM_RAMBAR |= MCF_SCM_RAMBAR_BDE;

MCF_SCM_GPACR0 = 0x04; //read,write

MCF_SCM_GPACR1 = 0x04; //read,write

and the Error in destination continues.

Thanks again

Gonzalo

Re: Problem with DMA and UART Tx (MCF52233EVB)

pslavkin — Sat, 05 Feb 2011 10:21:08 GMT

Hi Gonzalo, I'm Pablo, Have you solved your problem regarding DMA and UART?? I've exactly the same problem, on same board, and I'm still working on it without succes... Thanks in advance. Pablo.

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