clearing off RAM memory in IAR

Hi Gaurav,

When posting on these forums it is helpful to include what MSP430 you are using, your code if possible, and any other details. More details make it easier to help you through your problems.

-Mike

Mr. Michael Stein,

I apologize for i have not mentioned microcontroller. I am working on  MSP430F5438 and using MSP430FETUIF emulator.

my program is:-

function:- to transfer 16 word block from one RAM location to other using DMA.

#include "msp430x54x.h"

        RSEG  CSTACK
        RSEG  CODE
         
RESET   MOV.W #SFE(CSTACK),SP
        MOV.W #WDTPW+WDTHOLD, &WDTCTL
        bis.B #0x01,&P1DIR
        MOVX.A #0x1C00,&DMA0SA
        MOVX.A #0x1C20,&DMA0DA
        MOV.W #0x0010,&DMA0SZ
        MOV.W #DMADT_0+DMADSTINCR_3 +DMASRCINCR_3,&DMA0CTL
        BIS.W #DMAEN,&DMA0CTL
                    
MAINLOOP  bis.B #0x01,&P1OUT
          BIS.W #DMAREQ,&DMA0CTL
          BIC.B #0x01,P1OUT
          JMP MAINLOOP
                                         
                  COMMON INTVEC
                   
       ORG RESET_VECTOR
       DW  RESET
       END 

I am not able to clear RAM memory; it is showing some garbage values. Please help

thank you in advance.

hello,

I got the solution for my query. Just need to right click on selected memory part and use memory fill option.

regards.

gaurav mohta said:

I am not able to clear RAM memory

However, you never write anything to 0x1c00, so the ram there (is there ram?) contains whatever garbage was there after power-up.

try the following (in initialized data segment):

source DW 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15
destination DW 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0

and use MOVX.A #source,&DMA0SA etc.

It is not necessary to use the MOVX.A instruction. Both, operand (address) and destination (DAM register asddress) are 16 bit, so a simple MOV is shorter and faster and does the same.

thank you sir,

now i am able to transfer data successfully.

1 question, MOVX instruction is used in microcontroller 8051 to address external memory. Is it of same use in MSP430F5438?

gaurav mohta said:

MOVX instruction is used in microcontroller 8051 to address external memory. Is it of same use in MSP430F5438

Normal MOV takes only 16 bit addresses and 16 bit data. MOVA allows 20 bit data transfers from 20 bit addresses, CALLA calls a 20 bit address rather a 16 bit address, putting 32 bit return address on stack, and RETA returns to a 32 bit return asddress. All other A instructions can only work register to register, but with 20 bit data. They all fit into a 16 bit isntruciton word.
The X instructions require an additional extension word that keeps the additional 4 bits for source or destination addresses or 20 bit immediate values. They offer any combination of 20 bit addresses and 8/16/20 bit data sizes (.B, .W and .A dat amodifier). At the expense of 2 more bytes size and one more clock cycle (at least).

All instrucitons, however, address the very same internal memory area.