AnsweredAssumed Answered

imx233 wont boot from battery

Question asked by Peter Schumann on May 18, 2014

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.


0x000 0x00118024
0x010 0x00108503
0x020 0x00000040
0x030 0x00010000
0x040 0x0002071C
0x050 0x0000270C
0x060 0x00002614
0x070 0x00000110
0x080 0x00000018
0x090 0x00000000
0x0A0 0x0000305F
0x0B0 0x00167021
0x0C0 0x01001210
0x0D0 0x00FB0000
0x0E0 0x01FF040F
0x0F0 0x00000000
0x100 0x3E770002
0x110 0x00000000
0x120 0x00000000
0x130 0x03010000


Some times it loads UBoot but it always resets itself after some seconds.

Maybe somebody can help me out.