AT32UC3 not running at 3.3V, works fine at 5V...why?

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Hi guys, I am trying to use AT32UC3C264C at 3.3V (Partial schematic attached). For some reason i am not able to program it using Atmel Studio 7. 

If i change the voltage from 3.3V to 5V, it programs just fine.

I have checked that my fuses are off (see below):

 

LOCK0 = [ ]
LOCK1 = [ ]
LOCK2 = [ ]
LOCK3 = [ ]
LOCK4 = [ ]
LOCK5 = [ ]
LOCK6 = [ ]
LOCK7 = [ ]
LOCK8 = [ ]
LOCK9 = [ ]
LOCK10 = [ ]
LOCK11 = [ ]
LOCK12 = [ ]
LOCK13 = [ ]
LOCK14 = [ ]
LOCK15 = [ ]
EPFL = EPFL_NO_LOCK
BOOTPROT = BOOTAREA_0B
SECURE = SSDIS
UPROT = UPROT_ENABLE
BODLEVEL = <none selected>
BODHYST = BODHYST_ENABLED
BODEN = BOD_DISABLED2
BOD33EN = 0x00
SS_ADRF = 0xFFFF
SS_ADRR = 0x7FFF
WDTDISRV = WDT_DISABLE

FGPFRLO = 0xFFFFFFFF (valid)
USERPAGE_WORD_0 = 0xFFFFFFFF (valid)

 

Is there something i'm missing to make it work at 3.3V?

 

Thanks!

Attachment(s): 

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100 ohms in series with the 3.3v supply seems rather odd.  I don't know the specs of that particular part but 30 mA is about the average current draw I see with UC3A0/1 and UC3B0/1 parts.  If your UC3C is at all similar that 100 ohm resistor is killing your 3.3v supply.

Letting the smoke out since 1978

 

 

 

 

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I removed that 100 ohm resistor and I was able to program the device just fine! Thanks!

Just for reference the voltage regulator I am using is MCP1755T.