AM3354 and LSR wifi module

Calum Mackinnon

Other Parts Discussed in Thread: WL1271, TWL1200

Hi,

I have a couple of questions regarding Wi-Fi and the AM335X family of parts.

1st question - is there a ref design of connecting the LSR or Murata wi-fi module up to the AM335x part - I am thinking of using the TLW1200 to do the voltage translation but a ref design I could copy would really help. I'm actually using the LSR TiWi module

2nd question - I've been looking at some of the current ref designs - http://processors.wiki.ti.com/images/b/b8/TMDSSK3358_3H0009_REV1_2B_SCH_PDF.pdf

I have noticed that there is no level translation between the Murata module and the processor. Can the MMC bank of the processor operate in 1.8V mode and hence no need for level translation or is the Murata modules(I assume it's just the WL1271) IO 3.3v tolerant and that's how they get away with it?

Cheers

Calum

over 12 years ago

0 Biser Gatchev-XID over 12 years ago

TI__Guru**** 393215 points

Hi Calum,

1. The Starter Kit schematics you are referring to has a WLAN module connected. Check page 8.

2. The AM335X I/O cells are dual voltage (1.8V/3.3V). If you check the same schematics, you will see that VDDSHV1 is connected to VDIG1 voltage, which is 1.8V. And if you check the AM335X datasheet, Table 2-7 you will see that the SDIO signals to the WLAN module are connected to pads that are on the VDDSHV1 domain. All other signals go through level translators (Starter Kit schematics, page 8). The Murata module has 1.8V I/O levels. It isn't 3.3V tolerant. For AM335X, when I/O is operated at 1.8V it also isn't 3.3V tolerant.

0 Calum Mackinnon over 12 years ago in reply to Biser Gatchev-XID

Genius 4155 points

Thanks for the response.

We are using a SOM and don't have access to the power pins so we are stuck with 3.3V IO - so this leads me to the TWL1200 again - is there an app note or ref design on using the part? I have the datasheet but it's always nice to see an example. I see there is a one page schematic in the PCB design guidelines but if there was a full ref design it would really help.

Cheers

Calum

0 Biser Gatchev-XID over 12 years ago in reply to Calum Mackinnon

TI__Guru**** 393215 points

Hi Callum,

Have you checked this document: http://www.ti.com/lit/an/scea042/scea042.pdf. There is a reference schematic in it.

0 Calum Mackinnon over 12 years ago in reply to Biser Gatchev-XID

Genius 4155 points

Thanks Biser,

The doc you reference is the PCB guidelines doc I mentioned - I was a hoping for a AM335x ref design that uses it - showing the connections to the 335x and the wl1271/LSR module. If there isn't one that's OK, just hoping someone had done some of the work for me!!

Cheers

Calum

0 Biser Gatchev-XID over 12 years ago in reply to Calum Mackinnon

TI__Guru**** 393215 points

Hi Calum,

There is the Starter Kit schematics - on page 8 there is a WLAN module complete with level translators. You can use both schematics to create your own.

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AM3354 and LSR wifi module