STR912FAW46X6 Boot up problem

niroshpw · ‎2008-08-26

Posted on August 26, 2008 at 22:23

niroshpw · ‎2011-05-17

Posted on May 17, 2011 at 09:55

Hello,

We are doing some development work using an STR912FAW46X6(1MB) and are facing a problem. The symptoms are best described as:

1. Our board does not automatically start executing code upon power-up

2. The same code does execute on the IAR dev. board

3. We are unable to attach to a process running after power-up. Says ''Unable to Halt Arm9 Core''

Some further info:

1. Code executes when instructed to do so through debugger

2. J-Link can be unplugged while code running and it will continue to run ok until STR9 reset or power cycled

3. Reset line pulled high using 10K resistor. 0.1uF cap also present on line.

4. 25MHz Clock confirmed to be present.

5. Power and ground confirmed on all applicable pins.

Is anyone here:

1. Using an STR912DAW46x6(1MB version of STR912) in a design?

2. If yes, has anyone had any issues getting the code to start-up and run except through debugger? i.e. power cycle/reset and hace the code run

3. Aware of any hardware requirements except for power/gnd/reset/clock for code to start executing upon power-up?

Any words of wisdom will be appreciated.

Thanks

Nirosh

P.S. We did try erasing all memory using JLINK but it did not seem to make a difference to this issue.

niroshpw · ‎2011-05-17

Posted on May 17, 2011 at 09:55

Ok....for anyone who may be interested, it seems that the STR912 cannot deal with capacitance on the ''reset out'' line. If there is capacitance, the part does not start executing code unless initiated through the debugger.

A component we were controlling with this line had a 0.1uF at its input which was enough to stop the part from working.

Could it be that this pin does not have enough drive to keep up with the capacitance? Documentation does not indicate this to be a problem.