i2c issue when connected to sgtl5000

[deepanrajanbara]

Hi,

Ours is a custom board based on imx6 processor. We are using sgtl5000 as our audio codec. Our custom board is run on both battery powered and also through AC power. In initial testing, We tested the board with battery everything seemed to work fine. But when we try to charge the battery in between. The SGTL5000 card and also all other slave devices connected to the I2c is gone bad or is not valid for the processor even after a soft reboot. But everything works when the device is power cycled physically. We also checked with SGTL5000 errata and provided the workaround with external regulator but this issue persist only when the board is given a external power supply in between.

The entire I2C 1 is going bad after this issue and we are not able to control the i2C from the U-boot also. Please let us know is there anything we can check in software or hardware to ensure proper functional working of the i2c or the SGTL5000 codec.

Thank you,

Deepanraj.A

[igorpadykov]

Hi Deepanraj

if issue happens only with external power supply, this may point

to incorrect processor power up sequence. Please also check power

supply grounds and ripples of its output voltage. Note, no external voltages

should be provided to processor pins until all its power supplies become stable.

Power up sequence can be found in 4.2.1 Power-Up Sequence

i.MX 6Dual/6Quad Applications Processors for Consumer Products - Data Sheet

Best regards
igor
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[deepanrajanbara]

Hi Igor,

Is it possible that only i2c bus going bad in case the power supply is not proper.

If power supply is not proper the processor will undergo reset ?

Thank you,

Deepanraj

[igorpadykov]

Hi Deepanraj

deviation from recommended power-up sequence is described in

sect.4.2 Power Supplies Requirements and Restrictions :

The system design must comply with power-up sequence, power-down sequence, and steady state
guidelines as described in this section to ensure the reliable operation of the device. Any deviation from
these sequences may result in the following situations:
• Excessive current during power-up phase
• Prevention of the device from booting
• Irreversible damage to the processor

Best regards
igor