Nicholas Ipri

iMX283 power supply issues

Discussion created by Nicholas Ipri on Mar 7, 2012

Am trying to bring up a new iMX283 design using a single DDR2 chip.

On powerup, my VDDA voltage measures around 0.9v as opposed to the default of 1.8v.

My default VDDD and VDDIO voltages are 1.17v and 3.1v respectively, which appear to be in line with the default values set in the control registers.

 

I am booting from SD and I am using the power_prep bootlet provided in LTIB and am stepping through it to verify that the 4.2v reg is getting set up and enable properly along with the VDDD, VDDA and VDDIO DCDC converters. However, after bringing up the 4.2 v supply, I go to enable the DCDC converters and the voltages do not change. I am explicitly changing the TRG bits to set VDDIO and VDDD to 3.3 and 1.2 and writin gthose values to the control registers but the voltages do not change and neither does VDDA which remains at 0.9v. Something then decides to reset the processor core so the power_prep bootlet loads and runs repeatedly.

 

I can find no shorts or other abnormal loading of the VDDA supply and my total board current is only 60 mA.

 

Any suggestions would be greatly appreciated! Thanks in advance

Outcomes