The Atmel Controller will control the core voltage regulator enable signal by themself with the SHDN signal. But this signal is not working correctly, if VDDBU (the battery voltage) is connected. Atmel is publishing this error in the newest version of the AT91SAM9260 datasheet (pg 776, Shutdown Controller "SHDN Signal may be Driven to Low Level Voltage During Device Power-on"). In systems without battery this problem doesn't occur.
On our hardware fix we will enable the core voltage regulator all time without using the SHDN signal. This fix will be included on all delivered boards starting today. Older boards can be corrected by our repairing crew. Please contact your sales partner to get an RMA number.
Experienced customer can make this fix by themself.
KW
[attachment=0]<!-- ia0 -->Rework instruction PicoCOM1 to fix Atmel SHDWC bug.pdf<!-- ia0 -->[/attachment]
