• State
  • Locked Locked
  • Replies 3 replies
  • Subscribers 100 subscribers
  • Views 121 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

DRA821U-Q1: eMMC interface driver strength configuration

Max Chen1
Intellectual 905 points

Part Number: DRA821U-Q1
Other Parts Discussed in Thread: DRA821

Hi,

what is default eMMC I/O driver strength settings form SDK?

how can I change the I/O driver strength ?

Thanks

Max

 

  • 0
    TI__Genius 16520 points

    Hi Max,

    Can you help us with which SDK you are enquiring about:Linux SDK or RTOS SDK?

    Best Regards

    Gokul Praveen

  • 0 in reply to Gokul Praveen
    Intellectual 320 points

    We're using Linux SDK v10.1.

    1. Does DRA821's eMMC controller support optional I/O driver strength specified in JESD84-B51 (shown below)

    2. If answer to the first questions is yes, how can we change I/O driver strength to 40 ohm in Linux SDK?

  • 0 in reply to Charles Mao
    TI__Genius 16520 points

    HI Charles ,

    Charles Mao said:
    1. Does DRA821's eMMC controller support optional I/O driver strength specified in JESD84-B51 (shown below)

    yes, it should ideally support that driver strength.

    Charles Mao said:
    2. If answer to the first questions is yes, how can we change I/O driver strength to 40 ohm in Linux SDK?

    The below patch will change the driver strength to 40 ohm.

    diff --git a/arch/arm64/boot/dts/ti/k3-j7200-common-proc-board.dts b/arch/arm64/boot/dts/ti/k3-j7200-common-proc-board.dts
index 6867bfe67..97a5286c1 100644
--- a/arch/arm64/boot/dts/ti/k3-j7200-common-proc-board.dts
+++ b/arch/arm64/boot/dts/ti/k3-j7200-common-proc-board.dts
@@ -384,7 +384,7 @@ &main_sdhci0 {
        /* eMMC */
        status = "okay";
        non-removable;
-       ti,driver-strength-ohm = <50>;
+       ti,driver-strength-ohm = <40>;
        disable-wp;
 };

    Once the above patch is applied, please rebuild linux and its device tree , so that the dtb binary(k3-j7200-common-proc-board.dtb) will have these changes incorporated.

    Best Regards

    Gokul Praveen