Hi, VR1 is not assembled (NA). It is not placed. Only pads are provided in case you don't want to power the camera from the AXP209 but externally, in which case you should place VR1 and disconnect the SMT jumper LDO3_2.8V_E.
By original design the camera is powered only by the AXP209. Best regards, Lub On Monday, February 27, 2017 at 2:33:08 PM UTC+2, Marcus Weseloh wrote: > > Hi, > > 2017-02-27 13:11 GMT+01:00 oliver <oli...@schinagl.nl <javascript:>>: > >> One is to remove C185 (10 microF) and the problem went away. Looking at >> other designs, cubieboard 1 for example, uses the same layout, but only 4.7 >> microF. So it seems that charging of all the capacitance (input C106) the >> board itself, the output (C185) may be too much for the AXP209. >> > > Great, that confirms my suspicion that the capacitance is the main problem > on the A20-SOM. The reference design for the A20 from Allwinner also > suggests 4.7uF on LDO3, Olimex probably used 10uF there to keep the BOM > smaller? > > At least on the A20-SOM-EVB we have another problem though (as explained > in an earlier mail): When then SOM is attached to the EVB, the LDO3_2.8V > rail on the SOM is powered from the EVB via +5V and a DC converter. Even > with the LDO3 voltage set to it's minimum, turning on LDO3 shuts down the > AXP immediately. Probably because the AXP sees an external voltage applied > to it's input, it might even see reverse current flowing into it's ouput. > I'd say that this is a design flaw on the EVB. So at least on the > A20-SOM-EVB combination, LDO3 should never be be allowed to be switched on. > > Cheers, > > Marcus > -- You received this message because you are subscribed to the Google Groups "linux-sunxi" group. To unsubscribe from this group and stop receiving emails from it, send an email to linux-sunxi+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
