topic MX6Q eMMC throughput in i.MX Processors

MX6Q eMMC throughput

hankwang — Thu, 19 Nov 2020 02:34:00 GMT

Hi, we tested the eMMC write speed about 10MB/s. We run the FIO benchmark, the command is fio -filename=/dev/mmcblk3 -direct=1 -iodepth 1 -thread -rw=write -ioengine=psync -bs=4k -size=1g -numjobs=1 -group_reporting -name=test.

As I know, the i.MX6Q didn't support HS200 and HS400. Our eMMC is Micron 8G, the datasheet of Micron has description the max write speed 40MB/s with HS200/400.

We would like know what max write speed is for i.MX6Q? Thank you.

Re: MX6Q eMMC throughput

weidong_sun — Thu, 19 Nov 2020 03:32:20 GMT

Hi hankwang,

1. IMX6Q uSDHC Data TrThe uSDHC can select the following modes for data transfer:
• SD 1-bit
• SD 4-bit
• MMC 1-bit
• MMC 4-bit
• MMC 8-bit
• Identification Mode (up to 400 kHz)
• MMC full speed mode (up to 26 MHz)
• MMC high speed mode (up to 52 MHz)
• MMC DDR mode (52 MHz both edges)
• SD/SDIO full speed mode (up to 25 MHz)
• SD/SDIO high speed mode (up to 50 MHz)
• SD/SDIO UHS-I mode (up to 208 MHz in SDR mode, up to 50 MHz in DDR mode)

2. VDDIO on Hardware

When you need high-speed mode, the VDDIO voltage of the CPU and EMMC must use 1.8V.

Hope this information is helpful to you.

Have a nice day!

B.R,

Weidong

Re: MX6Q eMMC throughput

hankwang — Thu, 19 Nov 2020 03:48:56 GMT

Hi ,
Thank you for reply. we would like know which register can select these mode?
Do you have write speed data for voltage 1.8V ? Our board voltage is 3.3V for eMMC.
If the voltage is 3.3V, we can run which mode ?

BRs,

Hank

Re: MX6Q eMMC throughput

weidong_sun — Thu, 19 Nov 2020 04:50:24 GMT

For 3.3V IO, below speeds are all supported:

• MMC full speed mode (up to 26 MHz)
• MMC high speed mode (up to 52 MHz)
• MMC DDR mode (52 MHz both edges)

For eMMC4.4 or lower (from internet):

the parameters in the list meet those in i.MX6Q reference manual.

Have a nice day!

B.R,

weidong

Re: MX6Q eMMC throughput

hankwang — Fri, 27 Nov 2020 01:30:31 GMT

The max data transfer should be include read and write. The High speed DDR's max data transfer is 104MB/s. We guess this is read speed. Our eMMC datasheet has description this speed is 40MB/s for HS200/400. As I know, the i.MX6Q is not support HS200/400.But eMMC datasheet didn't show DDR speed. So far, we don't know what the ideal write speed should be.