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