Randy asks me to use DMA to access SDRAM in the following thread to improve the access time
https://e2e.ti.com/support/dsp/tms320c6000_high_performance_dsps/f/115/p/413541/1469170
I have implemented and measured the time
For loading 6912 32-bit words from a 16-bit SDRAM (7ns access time) on the EMIF bus, regardless the overhead, it would be
6912 words x 7 ns x 2 (2-beat burst for each word in order to fetch a 32-bit word) = 96.8 us
But the maximum quantum transfer size limit in dMAX event entry is 16 elements.
Quantum transfer up to 16 elements: I measured 480us. <-- this about 3 times faster comparing to use CPU access but it is larger than 96.8us calculated above.
Quantum transfer up to 8 elements: I measured 840us.
Quantum transfer up to 4 elements: I measured 1.44ms.
Quantum transfer up to 1 elements: I measured 5.24ms.
I would like to know is there any other place can be fine tune to reduce more access time. Thanks.