Hello TPS expert,
I'm working on a custom board that embeds an OMAP3503-TPS65950 couple.
During the active phase the following power resources are set to active:
- VDD1, VDD2, VIO, VPLL1, VINTANA1&2, VINTDIG, VMMC1. Others are in OFF.
During the idle phase (OMAP is in device-OFF mode), all power resources are put in OFF. Except the VIO which is left in SLEEP mode.
VIO is left in SLEEP mode to provide power to OMAP wakeup domain and also to maintain DDRAM content.
When the system goes in idle (OMAP toggles NSLEEP1 signal) I can see that the VIO voltage is going low at 0.5v whereas it is configured to stay in SLEEP mode (same if ACTIVE mode- thanks to VIO_REMAP register).
I have noticed that if VINTANA1 & VINTDIG are configured to stay in SLEEP mode also, then the VIO stays at 1.8v during idle.
What are the relationships and the dependencies between VIO and VINTANA1 & VINTDIG?
I found nothing significant in the TRM about this topic.
Another question related to the power resource configuration.
Why is it necessary to write an Active-to-Sleep sequence??
From TRM descrption the only configuration needed seems to be the following:
- Assign a resource to a group xxx_DEV_GRP.
- Configure resource behavior on sleep/off request with xxx_REMAP.
- Enable group state transition on NSLEEPx transition: Px_SW_EVENTS.lvl_wakeup bit.
Regards,
Nicolas.