Beagle Board: Issues in MMC3 interface

kasirajan ganapathi

Other Parts Discussed in Thread: TXS0108E, TXS0206

We have used Level converter “TXS0108E”in our design. Port A of this level converter permanently connected to 1.8V rail (VCCA-1.8V) and option being given for the port B, either it can be connected to 1.8V/3.3V SDIO interface. This board is working with Beagle boardC4/B6 in MMC1slot irrespective of the configuration (VCCB is 1.8V/3.3V). But it's not working with Beagleboard-xM in MMC3 (1.8V) interface.

We have not provided any pull-up resistors in our design since TXS0108E consist integrated pull-up resistors.

The only difference what we could see in the BB-xM is : There is no pull-up resistors in the MMC3 interface. Where as in MMC1 interface, there are 10K pull-up resistors.

Even we tried placing 10K pull-up resistors in the host side, but there is no improvement.

what could be reason ? Why it's not working with MMC3 interface?

Thanks in advance,

Regards,

kasirajan G

over 14 years ago

0 Hattie over 14 years ago

TI__Genius 9085 points

Do you have waveforms available for the working and not working signals?

The TXS0206 is another option when translating an SD interface.

0 kasirajan ganapathi over 14 years ago in reply to Hattie

Prodigy 80 points

We have probed only CMD and CLK line. The problem is; card initialization itself is not working. Here is the waveform for working and non-working board. Please let us know what we suppose to do? so that card initialization happens without an issue.

i am using TXS0108E level converter & configured for 1.8V both sides (VCCA-1.8V,VCCB-1.8V)

working wave form:

Non working waveform:

Thanks & regards,

kasirajan G

0 Hattie over 14 years ago in reply to kasirajan ganapathi

TI__Genius 9085 points

Since it does not work at the 1.8V point, have you tried to initialize without the TXS0108E device?

Do you have waveforms that show the rise and fall times of the signals?

Logic

Logic forum

Beagle Board: Issues in MMC3 interface