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Original question:

AM3352: Reconfiguring I2C in Multi-Master environment

AM3358: Multi-Master I2C

Paul L
Prodigy 240 points
Part Number: AM3358

hi,

1) I'm wondering if there is any updated HW available after our debug and conf  calls a couple of years back discussing the I2C peripheral in use on the AM335x.

I saw there was some further activity and workarounds suggested in Oct 2016. There was some mention of re-spinning the I2C peripheral HW.

The older discussions: http://e2e.ti.com/support/arm/sitara_arm/f/791/p/514961/1940239#pi316653=8

2) Another thing I wanted to ask, is, if the PRU-ICSS system could be configured as a MM i2c unit? Doesn't look like it's currently on the list. Is this feasible?

https://e2e.ti.com/support/arm/sitara_arm/b/sitara_announcements/archive/2016/08/02/pru-icss-industrial-software-for-sitara-tm-processors-v1-00-00-released-for-am57x-future-support-on-am335x-amp-am437x-as-well

  • 0
    TI__Guru**** 393215 points
    1. The latest silicon revision for AM335x devices is SR2.1. The AM335x Errata document shows all known issues and which silicon revisions are affected by them: www.ti.com/.../sprz360i.pdf

    2. This seems feasible, but at present TI has no PRU software solution for I2C implementation.
  • 0 in reply to Biser Gatchev-XID
    Prodigy 240 points

    thanks Biser.

    I found this related document. Could the AM335x I2C block additionally be affected by any of the i2c errata listed here?

    http://www.ti.com/lit/er/sprz319f/sprz319f.pdf   - thanks. Paul.

  • 0 in reply to Paul L
    TI__Guru**** 393215 points
    This is a completely different device. AM335x Errata can be found here: www.ti.com/.../sprz360i.pdf
  • 0 in reply to Biser Gatchev-XID
    Prodigy 240 points

    Indeed, but I believe we were previously referred to the DM37x I2C section of the spec when we spent time debugging the Sitara I2C back in 2016, which I why I linked this.

    So the I2C silicon is not related?

    The AM335x errata is not very detailed w.r.t I2C, I am not sure if that is because

    1) the same issues have not been checked there, or

    2) the AM335x is certified free of these defects.

    Which is the case?

    There are some very interesting errata there about :

    1.7 RDR may be incorrectly set

    1.43 XUDF not functional in Slave TX

    1.93 wrong behaviour ...SBLOCK

    1.94 After Arb loss, module incorrectly starts next transfer

    Now, as we ourselves found that the AM335x I2C block does not behave very well in multimaster, I want to know for certain that these errata DO NOT apply to the AM335x.

    Can you please check this with the design teams.

    FYR I need to get the I2C block working in master mode, where another HW may be performing slave operations (since the Sitara I2C slave does not seem to work = previous threads)

    but there seems to be some misbehaviour around Arb loss.

    Having some good detailed errata about everything that will be a hurdle would be a vital help.

    Can you also refer me to a more detailed description of how the SBLOCK should be used?

    best regards

    Paul

  • 0 in reply to Paul L
    TI__Genius 15920 points
    Hi Paul,

    The DM37x I2C errata are not known to apply to AM335x.

    Also, here's some additional details about SBLOCK. This feature offers the possibility for the Local Host to command the blocking of the I2C clock after the Address Phase, if the module is addressed by an external master using a certain address.

    Regards,
    Melissa