TC377 TriBoard P33.5 LED Flashing

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User21934
Level 1
Level 1
I have just received a TriBoard TC3x7 evaluation board with TC377TE microcontroller fitted.

When I received the board, the microcontroller was already programmed with a test application which flashed 5 of the 8 LEDs on the board.

I have erased this test application and programmed in a very simple test application which has no IO configured, but LED D303 is still flashing.
According to the TriBoard manual, D303 is connected to P33.5 on the microcontroller. When I look at P33 registers with a debugger, P33.5 is configured as an input and the state is alternating high and low.
The LED continues to flash even when the microcontroller is held in reset by the debugger.

So, what is driving the P33.5 / D303 line on the TriBoard? It does not appear to be connected to anything else on the schematic in the manual.
Can I use P33.5 as PWM output from the microcontroller without risking damage to the microcontroller or the TriBoard?

I have a colleague with the same TriBoard who is seeing the same LED flashing when the processor is held in reset, so I have no reason to believe that my board is faulty.
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cwunder
Employee
Employee
5 likes given 50 likes received 50 solutions authored
The demo software has code for the SCR (Standby Controller) which will blink the LED on P33.5. If you put your own code in the Flash and perform a cold power on reset (remove power) then it should not run anymore as the SCR needs to be loaded from the Flash.
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User21934
Level 1
Level 1
That's it. Thank you.
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