We have several custom systems based on i.MX53 and i.MX6x SoCs using the SGTL5000 audio codec and a dialog DA9063 PMIC; both connected to the same I2C bus of the i.MX-SoC.
Now we're facing serious troubles due to the SGTL5000 Errata #ER1: "Internal Vdd regulator does not start up". Although the errata claims this problems "is very rare" we experience this problems on some boards up to ~50% of the power-cycles; the more often these boards a (re-)started, the more often the problem occurs. Power-cycling the board, when this errata happens, usually bring the SGTL5000 back to life, but as the SGTL5000 and the PMIC, which also indirectly powers the SGTL5000, (and some more I2C devices) are connected to the same I2C bus on our systems, this errata also "cuts-off" any communication with the PMIC, when it happens. The board becomes unusable and must be power-cycled manually by the customer.
Does anybody have any idea, how we might be able to power-cycle a DA9053 PMIC via software, without being able to use its I2C-interface?
The DA9053 pins usually meant for a power-cycle or shutdown don't seem to be usable on our system(s):
- nSHUTDOWN is constantly pulled high (no SW control)
- GPI14 & GPI15 are unconnected
- nONKEY/KEEP_ACT is connected to PMIC_ON_REQ of the i.MX53, but to power-cycle the DA9053 via this pin a 5s-pulse must be generated. As far as we can see in the i.MX53 documentation, PMIC_ON_REQ is only controllable indirectly via the ALARM-function of the SRTC and the i.MX53 reference manual implies, that this function is only intended to cause a (short?) wake-up pulse on this pin.
Is it possible to generate a 5s pulse via the PMIC_ON_REQ-pin of the i.MX53 is some (undocumented?) way? Is it possible to restart the SGTL5000 in some way, once the errata #ER1 has occurred?
Thanks for your help.