New eMMC for a customized TK1 board

Robotics & Edge Computing Jetson & Embedded Systems Jetson TK1
1

Hi All,
We made a customized TK1 board.
We want to know, if the eMMC we use is different from the one used in the TK1 development board, do we need to fine-tune any parameters?

3

No need to tune that if follow Design Guide well.

4

Hi, Trumany,
If we do follow the design guide well, is there suggestion that you can provide ?
As our former eMMC is phase out and then we use a new brand, the new brand of the eMMC seems not stable in writing.
Here are our testing result :

#0084867171

ubuntu@tegra-ubuntu:~$ dd if=/dev/zero of=/home/ubuntu/test.txt bs=8k count=10k

10240+0 records in

10240+0 records out

83886080 bytes (84 MB) copied, 0.389806 s, 215 MB/s

ubuntu@tegra-ubuntu:~$ dd if=/dev/zero of=/home/ubuntu/test.txt bs=8k count=10k

10240+0 records in

10240+0 records out

83886080 bytes (84 MB) copied, 0.397265 s, 211 MB/s

ubuntu@tegra-ubuntu:~$ dd if=/dev/zero of=/home/ubuntu/test.txt bs=8k count=10k

10240+0 records in

10240+0 records out

83886080 bytes (84 MB) copied, 1.10178 s, 76.1 MB/s

ubuntu@tegra-ubuntu:~$ dd if=/dev/zero of=/home/ubuntu/test.txt bs=8k count=10k

10240+0 records in

10240+0 records out

83886080 bytes (84 MB) copied, 1.80298 s, 46.5 MB/s

ubuntu@tegra-ubuntu:~$ dd if=/dev/zero of=/home/ubuntu/test.txt bs=8k count=10k

10240+0 records in

10240+0 records out

83886080 bytes (84 MB) copied, 1.37497 s, 61.0 MB/s

ubuntu@tegra-ubuntu:~$ dd if=/dev/zero of=/home/ubuntu/test.txt bs=8k count=10k

10240+0 records in

10240+0 records out

83886080 bytes (84 MB) copied, 0.404695 s, 207 MB/s

P.S.: Same PCB design within old eMMC are working well. All we did is exchange a compatible eMMC merely.

5

Did you check the signal waveform to see if it follow the SDMMC spec? If the signal quality is not so good, you can check the SDMMC part in Technical Reference Manual to change the drive strength and etc. if necessary.

7

Hi Trumany,
The manufacture of the eMMC suggest us turn on cache and trim functions. We would like to know if TK1 support and has enabled these two functions!?

Many Thanks.

10

Hi,

By default, the TRIM should be enabled. On those devices do not support TRIM, we get timeouts for Erase commands.
Cache support is enabled during eMMC device init.

You can check “mmc_cache_ctrl” function in kernel/drivers/mmc/core/core.c

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