Tiwi5 (wl1273L) interface with MMC2 (AM3352)

SUNIL KOTTARY

Other Parts Discussed in Thread: AM3352

I am trying to Interface TiWi5 module with MMC2 on AM3352 based custom board, which is not successful.Earlier i had tried MMC1 with TiWi5 in beagle bone without much issues.

MMC2 is not able to initialize the module.I can see clock and command but no response from tiWi5 module.

I could see the clock of 400KHz in SDIO_CLK and some data on SDIO_CMD. I could not see any data (voltage transition) on irq and SDIO lines.

In few threads i found MMC2 can operate only in 1.8V .Can anybody confirm on that .TiWi5 module uses 1.8V and we have put voltage translator between processor which uses 3.3V

How can i debug the interface ?

I have attached the logs for reference.

Sunil kottary

over 11 years ago

0 Biser Gatchev-XID over 11 years ago

TI__Guru**** 393215 points

Hi Sunil,

Since you have started a new thread I am moving the discussion here.

SUNIL KOTTARY said:

Hi Biser

This is my pin mux configuration. mmc2 operate in 3.3v and Tiwi5 operates in 1.8 voltage and we have voltage translator between them. TiWi module is small daughter card and we are operating the processor at 25MHz.

static struct pinmux_config mmc2_wl12xx_pin_mux[] = {
{"gpmc_a1.mmc2_dat0", OMAP_MUX_MODE3 | AM33XX_PIN_INPUT_PULLUP},
{"gpmc_a2.mmc2_dat1", OMAP_MUX_MODE3 | AM33XX_PIN_INPUT_PULLUP},
{"gpmc_a3.mmc2_dat2", OMAP_MUX_MODE3 | AM33XX_PIN_INPUT_PULLUP},
{"gpmc_ben1.mmc2_dat3", OMAP_MUX_MODE3 | AM33XX_PIN_INPUT_PULLUP},
{"gpmc_csn3.mmc2_cmd", OMAP_MUX_MODE3 | AM33XX_PIN_INPUT_PULLUP},
{"gpmc_clk.mmc2_clk", OMAP_MUX_MODE3 | AM33XX_PIN_INPUT_PULLUP},
{NULL, 0},
};

Sunil

0 Biser Gatchev-XID over 11 years ago in reply to Biser Gatchev-XID

TI__Guru**** 393215 points

The pinmux seems OK. I have several questions:

1. What are your VDDSHV2 and VDDSHV3 voltages?

2. What is the voltage translator part number? How is it connected?

3. Did you check the pinmux settings after the kernel has booted, from the debugfs? If you have not verified it this way, please go to the omap_mux dir inside the debugfs:

cd /sys/kernel/debug/omap_mux/

and then cat the desired pin configurations:

cat <pin_name>

This is to verify that nothing is modifying the pinmux configurations you expect to see.

0 SUNIL KOTTARY over 11 years ago in reply to Biser Gatchev-XID

Intellectual 460 points

Hi Biser

1.Both VDDSHV2 and VDDSHV3 are connected to 3V3.

2.We are using PIULS5V102UE. Schematic is attached with this mail.

3.Yes verified the pin mux after system booted that also looks good.find the attachment.

Sunil kottary

0 Biser Gatchev-XID over 11 years ago in reply to SUNIL KOTTARY

TI__Guru**** 393215 points

I cannot find anything that matches PIULS5V102UE on the Internet. Neither can I see the schematic. Are you sure you typed the part number correctly? The pinmux seems OK.

0 SUNIL KOTTARY over 11 years ago in reply to Biser Gatchev-XID

Intellectual 460 points

Hi Biser

Please find the schematic sorry missed the exact part number PI4ULS5V102UE

Sunil

0 Biser Gatchev-XID over 11 years ago in reply to SUNIL KOTTARY

TI__Guru**** 393215 points

Hi Sunil,

The PI4ULS5V102UE datasheet states that VCCA must always be less or equal to VCCB. In your schematic it's the other way around: VCCB < VCCA. This could easily distort the signal enough so that traffic on the MMC bus fails.

0 SUNIL KOTTARY over 11 years ago in reply to Biser Gatchev-XID

Intellectual 460 points

Hi Biser

Yes this was an error and we have corrected it.Board i am working has the re-work.

Sunil

0 SUNIL KOTTARY over 11 years ago in reply to SUNIL KOTTARY

Intellectual 460 points

Hi Biser

I have a good news and bad news.Good news is that MMC2 is working with low speed (400KHz). With this clock speed wifi module is up and i am able to connect to Access point and able do data transfer.This confirms that MMC2 interface works fine.From the logs i have sent earlier i figured it out low speed operation working fine and the moment speed is changed to 25MHz initialization stated to fail, So i have limited the clock speed to 400KHz in kernel.

Bad news is that module does not work with High Speed(25MHZ) .I have tried 1MHz, 10MHz ,15MHz, 20MHz, 25MHz clock speed and interface does not seems to work.

Any idea what can cause the module not to work in High Speed ?.Does the voltage translator can have an effect on high speed operation ?

Sunil Kottary

0 Biser Gatchev-XID over 11 years ago in reply to SUNIL KOTTARY

TI__Guru**** 393215 points

Hi Sunil,

Are the MMC traces long? Do you have a 22Ohm serial resistor on MMC_CLK, placed close to the processor? What you describe can be caused by signal reflections on the lines.

0 SUNIL KOTTARY over 11 years ago in reply to Biser Gatchev-XID

Intellectual 460 points

Hi Biser,

I don't think traces are too far.I have attached the board picture and we have TiWi5 module as a daughter card.

Yes ,We have 22 Ohm resistor near to the Processor and 33 Ohm resister near the TiWi5 chip.

Sunil Kottary

0 SUNIL KOTTARY over 11 years ago in reply to SUNIL KOTTARY

Intellectual 460 points

Hi Biser

Good news i am able MMC2 works with high speed .i got new board with clean changes and MMC2 works with 25MHZ.

Sunil kottary

0 Biser Gatchev-XID over 11 years ago in reply to SUNIL KOTTARY

TI__Guru**** 393215 points

Great news Sunil! Thanks for updating the thread.

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Tiwi5 (wl1273L) interface with MMC2 (AM3352)