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SAM-BA does´nt work...pleas help urgnetly...

Posted: Wed Sep 19, 2007 7:06 pm
by ManuelSahm

My Problem:
I do the following steps:
1.) Voltage OFF
2.)Drive PA0,PA1,PA2, TST Pins HIGH (3,3V)
3.)Voltage ON
4.)TST = LOW; PA0,PA1,PA1 = unconnected
5.)Voltage OFF
6.)Voltage ON

Now the SAM-BA Boot Mode must be enabled, but is isn´t. The DBGU ist initialiszed. The DTXD Pin falls from 3,3V to 2,8V.(Not initialized as an Output).
There is no voltage on the PLL Filter...

On another Board Layout it´s working??? but why???
Microcontroller = AT91SAM7S128
XTAL is standard 18,34 MHz...PLL Filter 1,5k, 1nF 10 nF...(Standard)

What could be the problem ?

Which Pins are ALWAYS necessary, which PINS are checked at the beginning of SAM-BA boot mode initialization...

please help, I Don´t now how to go on...

Posted: Fri Sep 21, 2007 3:36 pm
by mcgregor
How long do You wait beetween step 3 and 4 ? - according to Atmel's documentation it takes at least 10 seconds to copy SAM-BA boot code from internal ROM to the first two sectors of FLASH.