Hi, On 15. 04. 20 14:05, Benedikt Grassl wrote: > Hi Michal, > > I just tried to check if the read performance acutally increased when > using an 8-bit data bus. As a quick test, I use the fatload command to > read a chunk of 1 GByte from an eMMC flash (generated with dd from > Linux). However, I don't see any difference at all: > > mmc info > Device: mmc@ff160000 > Manufacturer ID: 9d > OEM: 101 > Name: IS016 > Bus Speed: 200000000 > Mode: HS200 (200MHz) > Rd Block Len: 512 > MMC version 5.0 > High Capacity: Yes > Capacity: 14.6 GiB > Bus Width: 4-bit > (...) > > fatload mmc 0 ${loadimage} test.img > 1070579712 bytes read in 70458 ms (14.5 MiB/s) > > With an 8-bit data bus: > > mmcinfo > Device: mmc@ff160000 > Manufacturer ID: 9d > OEM: 101 > Name: IS016 > Bus Speed: 200000000 > Mode: HS200 (200MHz) > Rd Block Len: 512 > MMC version 5.0 > High Capacity: Yes > Capacity: 14.6 GiB > Bus Width: 8-bit > (...) > > fatload mmc 0 ${loadimage} test.img > 1070579712 bytes read in 70551 ms (14.5 MiB/s) > > I wonder if the fatload command is the bottleneck here? Unfortunately > I'm working from home right now and don't have an oscilloscope at hand > to verify in hardware. Do you have any inputs on that?
you can do raw write to avoid fat FS which is not optimal. Thanks, Michal