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In my system I have a FIFO of width 16 bit on EMIFA connected physically on bits D[15..0] . And on the same EMIFA I have an SDRAM width of 64 bit . I wont to transfer the data from the FIFO to the SDRAM . If I will use the PDT feature and EDMA transfer ( It is still not working but will work on ver. 1.1 !!! ) the data read from the FIFO will be written only to the low 16 bit of the memory and I will waste 3/4 of the SDRAM so this PDT feature is nice but not useful in this case . So I have to make the transfer using normal EDMA transfer not using the PDT feature . I am not sure how will the data from the FIFO spread in the mmory - will it be written on all the 4 byte of the SDRAM byte after byte ? ( using all the 64 bits width ? ) . How much time will it take to transfer a FIFO of 16K byte depth to the SDRAM - how can I calculate the time ? (The SDRAM and FIFO work on clk of 133 Mhz ) . In the doc. of the EDMA it is not mentioned the size of the internal memory of the EDMA and how to make this calc. Is there any info. about the comparison of the two way's of transfer the way using PDT compared to not using PDT but in both cases using EDMA transfer of a FIFO width 16 bit to an SDRAM of 64 bit width ? What will happen if I will use in my case of transferring 16 bit FIFO to 64 bit SDRAM the EDMA using : ( See SPRA636A appendix B Figure B-1 ) Element Sync. 1-D SUMb to 1-D DUMb . Option (OPT ) : PRI - 001 , ESIZE - 01 , 2DS - 0 , SUM - 00 , 2DD - 0 , DUM - 01 , TCNT - 0 , TCC - 0000 , LINK - 0 , FS - 0 AND el_cnt = 0x1 , fr_cnt = FIFO depth OR el_cnt = FIFO depth , fr_cnt =0x0 source address = the FIFO address , destination address = the SDRAM address . Will one of this modes solve my problems ? And what will be the throughput of the transfer ? Tank's Gabriel Drenger Elbit Vision Systems Tel : 972-4-9936431 E-mail : |
FIFO and SDRAM on EMIFA on DSP C6415
Started by ●July 8, 2002
