adjust usdhc bus stength

MCW · ‎09-21-2023

Hi all,

The strenght of usdhc signal is too strong, so I consider it could reduce the life of imxrt1061.

I find two ways to adjust the strenght of usdhc signal.

1. Change the DSE

The problem of overshoot and undershoot signal is solved when I set to DSE_1_R0_150.

But it causes the other problem whish is the rising time and falling time become longer.

2. Use SD_SetDriverStrength()

However, the second way (SD_SetDriverStrength() api) cannot support the sd card without SDR50 mode.

So, is there any other solution to alleviate the strength of usdhc bus signal?

Best regards,

Doris

jingpan · ‎09-26-2023

Hi @MCW ,

SD_SetDriverStrength() change SD card driver strength.

You can refer to table12-2 in RM. It is a matrix of DSE, SPEED and SRE field.

Another way to improve the EMI is add 0 ohm or small resistor into the bus.

Regards,