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Altera_Forum
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14 years ago

use descriptor chain in SGDMA

Hi all My current goal is to use SGDMA (ST-to-MM) to transfer video data to a memory. Later on, I'll replace the memory by PCIE IP. My problem is how to use descriptor chain in SGDMA. ...
Altera_Forum's avatar
Altera_Forum
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14 years ago

Hi Daixiwen

Thank you for the reply.

I use an on-chip memory for storing the descriptor.

The address of the on-chip memory is from 0x00040000 to 0x0004ffff.

The Nios II (data_master) and SGDMA (descriptor_read and descriptor_write) are connected to the on-chip memory.

I declare my descriptor table in the following code. 


sgdma_desc = (alt_sgdma_descriptor*)ONCHIP_DESC_MEM_BASE;

ONCHIP_DESC_MEM_BASE is defined in system.h as follows: 


# define ONCHIP_DESC_MEM_BASE 0x40000

For your last question, ("which memory is used for text, data, heap, stack and bss?") I don't know how to figure out these data in my program. Could you please give me some clues?

Thanks.