Hi expert,
At present, the hardware test indicate that the emmc of tda4 shows insufficient driving ability, when using default DR_TY (50 ohms), the waveform shows as below:
what we need is shorter rising edge and falling edge time. At default, the rising edge time is 2.5ns and our target is within 2ns.
We modified related register, and the driving ability is still not improved after modification (the modified register is as follows)
below are the waveform when using different DR_TY values:
when DR_TY = 4 （40 ohms）
when DR_TY = 3 (100 ohms)
From looking at the waveform, the driving ability of emmc get worse either turn DR_TY larger or smaller. Two things I want to make sure:
1. Where I change DR_TY value is shown in the following picture. Is that true?
2.If the method we config DR_TY is right, then why the waveform get worse than using default DR_TY? and how can I change the driving ability of emmc?
thank you
