Hi Rakshith,
it was also quite easy to increase SDHC buffer in Modus 2.0 from 64KB to 448KB.
One just had to change SDHC mode from default in syhal_sdhc.c ADMA2 to SDMA.
It seems to be that ADMA2 has 64KB limit, but SDMA has not. Thus, switching the
mode automatically allows to use larger buffer to boost data rate. To change this
setting one just can override the library function where it is set cyhal_sdhc_init()
with another function that has required SDHC mode inside (SDMA). Perhaps, this is
not an universal solution because some function of the library may change their
behavior with SDMA. I did not test this. However, read/write works just perfect:
Starting write the 1st 448K block
Duration: 13523 us, Data rate: 33.924 MBps
Starting write the 2nd 448K block
Duration: 13523 us, Data rate: 33.924 MBps
Starting read the 1st 448K block
Duration: 10520 us, Data rate: 43.608 MBps
Starting read the 2nd 448K block
Duration: 10520 us, Data rate: 43.608 MBps
Interestingly, but cy_sd_host.c library in Modus 2.0 has only tiny improvements
comparatively to library in Modus 1.1. Necessity to reinitialize the card after each
operation in my code in Modus 1.1 was caused by some omissions.
In fact, SDHC works equally well in Modus 1.1 and 2.0, but Modus 2.0 adds
convenient high level library cyhal_sdhc that is lucking in 1.1.
Now the question about SDHC performance is closed completely.
Thank you very much for your help.
Happy programming!
Alexei
