Am 09.11.2016 um 14:41 schrieb Matthijs van Duin <matthijsvanduin@gmail.com>:

On 8 November 2016 at 21:06, H. Nikolaus Schaller <hns@goldelico.com> wrote:

  - we need to be able to boot from eMMC or the µSD (needs proper control of
    the TXS02612 switch (in MLO, U-Boot and Kernel)

Isn't control of that switch handled in hardware by default after reset?  Otherwise ROM wouldn't be able to load MLO in the first place.

Yes it is so that by default it comes from eMMC unless you press a shoulder button.

But this must be disabled by MLO or pressing the shoulder button later turns the switch and can't be used as shoulder button any more.

At least this has to be modified.

  - we need an MLO/U-Boot/Kernel variant that switches pinmux of the SD interface

That doesn't sound like a problem

  - we need a SD shaped hardware adapter to get the JTAG signals to a probe

This, however, is the tricky part. It would have to be custom made since the (already obscure) NIDnT interface is based on micro-SD.

If you can specify a connector I can design such an SD card shaped adapter. Or if it is sufficient it can have some solder rings for GND and the JTAG lines.

maybe with level-shifters (I don't know)

No need

Good to know.

 

  IMHO this has a high chance to find out in which state the Palmas is.

I don't suppose there's any way to physically access the i²c bus palmas is on? Since that would obviously also allow it to be interrogated.

Ah, interesting idea!

Yes.

We have an EEPROM on the CPU board connected to the same bus which is physically big enough to easily solder three

wires (GND, SCL, SDA) and then trace all activities.

Or even become bus master (if OMPAP5 is silent) to query the Palmas state.