How to use EDMA to undertake digital video signal transmit

From;  Author:Stand originally

[summary] put forward how to use EDMA to transfer digital video signal older memory from lesser buffer, comprise the method of a whole picture through sort.

1, foreword

Existing TV uses interlaced scanning technology more in the technology, accordingly, the digital video signal that earning of direct to composite signal sampling goes to, its picture news is discontinuous. And in technology of contemporary image processing, of adjacent of photograph of the position in often using image like the gray scale between element the relation has all sorts of operation, accordingly, the video signal after must alternating D of course A / undertakes sort is handled, a whole picture is formed in memory. EDMA (EnhancedDirectMemoryAccess) it is to point to in TMS320C6x11 / C64xDSP, below the circumstance that participates in without CPU, realize the data move between each memory of DSP. We go with filter of a FPGA first in the system the blame picture news in digital video signal, next, use EDMA will treated digital signal from lesser buffer (like double mouth RAM) transfer older memory, comprise a whole picture to offer DSP processing.

2, register of setting EDMA optional parameter

2. 1EDMA transmits parameter group to summarize

EDMA transmits parameter group to be formed by 6 32 words, use definition EDMA to transmit a process, include computation of address of optional parameter, source, target address, data, address to revise letterhead of index, link all sorts of register. Optional parameter register decided the transmission way of EDMA, share 10 kinds of control, basically elaborate below how to install optional parameter register.

2. 2 settings transmit data unit

EDMA support is opposite 8, 16, the memory of 32 data, 8 use to signal of image gray scale in this system quantify, the outside data line of DSP is 32, then, can be worth 4 like the gray scale of element incorporate a data is unit (Element) , add up to 32, accordingly, the ESIZE in register the setting is 00b.

2. 3 settings transmit dimension and address to replace kind

The video signal after digitlization is in buffer (source data area) in store continuously, the address is growth (SUM = 01b) , can regard one dimension as (2DS = 0b) . In target memery block, image data is to press what deposit all right, and the check the number of every group of each row number and video signal is same, such, the memory of target data division turns into structure of a planar (2DD = 1b) . The address also is growth (DUM = 01b) , the byte that travel and between-line spacing need to deposit place of signal of a TV is counted, can come true through installing FRMIDX register. Such, want to install the initiative address that deposits odd field and even field signal to differ only, can get a whole picture in target memery block. Graph 1 to transmit sketch map.

2. Generation of the EDMA after 4 settings transmit an end is interrupted
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