AM5728: AM572x-Sitara Pinmux issue

Sathish Jisha

Part Number: AM5728

Hi team,

I am going to purchase TI-5728 Sitara processor. I am used PINMUX Tool and checked my pins GPMC and QSPI pins are conflict. I saw message like this "gpmc_a16 is currently in use by QSPI1 - Flash"..

Is this possible to use gpmc_a16/U1 pin for both GPMC address and QSPI data in software application? Attached the PINMUX tool output files for reference.all (1).zip

over 4 years ago

0 Sathish Jisha over 4 years ago

Prodigy 50 points

Hi team,

please support for my query as soon as possible.

Regards,

Sathish

0 Sathish Jisha over 4 years ago

Prodigy 50 points

hi team

please support regarding my issue as soon as possible.

0 Robert Eschler over 4 years ago

TI__Guru 51635 points

The QSPI pin D0 is not available on any other pin - thus it must use pin U1 if QSPI flash is to be supported.

GPMC_A16 is available on 3 different pins - U1, R6, K6. Its also stated that U1 will be used by QSPI. Can your application use either R6 or K6 for GPMC_A16?

Will you need boot access to either of these memories? With the above selection of pin U1 for QSPI - I believe QSPI boot will be supported, but no GPMC.

0 Rajesh War over 4 years ago in reply to Robert Eschler

Intellectual 525 points

Hi Robert,

U1 - QSPI_D0 (Booting)

R6 - Not showing in pin mux tool to use as GPMC_A16.

K6 - GPMC_A22. If I change this... it is conflicting with other GPMC pins. We have narrowed out the conflict to single pin. Can I able to use this pin both for QSPI and GPMC(not in parallel)

0 Robert Eschler over 4 years ago in reply to Rajesh War

TI__Guru 51635 points

The two functions on one pin certainly could not be used at the same time. The mux mode setting for the pin selects only 1 function - either QSPI or GMPC. This is typically set to its desired value once after boot, and not changed afterwards. However - nothing limits the mode from being changed at any time.

0 Rajesh War over 4 years ago in reply to Robert Eschler

Intellectual 525 points

Hi Robert,

Do you mean we can change the MUXMODE of the pin after bootup? Can you confirm below sequence is possible or not?

1. At Boot time pin U1 used for QSPI boot flash.

2. U1 to be changed to GPMC_a16.

3. GPMC read/writ happens.

4. U1 to be change to QSPI data.

5. QSPI read/write happens.

4. Step 2 to 5 repeats.(in sequential manner)

0 Robert Eschler over 4 years ago in reply to Rajesh War

TI__Guru 51635 points

Yes - MUXMODE defines how the pin will be used. Internal to the chip you can enable both QSPI and GPMC - but only 1 function can be supported at the pin level (as any given time). What you describe is theoretically possible - but I'm not sure its practical. I was thinking default to QSPI, complete the full boot (QSPI is no longer needed), and then switch to GMPC. I'm not sure how switching back/forth will work (how pin management is accomplished) - certainly TI has not tested/supported.

There would also be complications on the PCB layout, as QSPI data signal would be connected to GPMIC address signal (might impact signal quality).