Hi, i am trying to run my Olinuxino-micro from batterty but have found some strange problems.
My intention was to code a kernel driver for the power block in the imx233 because there is no mainline support for it.
In the progress I tried to do a VDD5V to Battery transition which is very unstable. The soc seems to brownout .
The board is already running from DCDC before VDD5V is removed is there is no critical timing...
I observed some strange things while scoping the powerrails:
1. If 5V Rail is floating around 3V the system runs fine on Battery all day long. (5V Power Supply removed)
2. the VDDD Rail drops first, around 500us before VDDIO
3. It looks like brownout reset or some thing but all brownout hw features and interrupts are disabled.
4. With some usb device connected it resets immediately because the 5V Rail is loaded.
I modified UBoot spl to dump the power registers after its power initialization is done.
Some times it loads UBoot but it always resets itself after some seconds.
Maybe somebody can help me out.