Can not program device

[Sergy]

Hi,

I have 2 pins that connected to transistors that turn on high-side FETs. One turns on 3.3v for the rest of the system and another one 4v.

When I turn on 3.3v everything is fine, but when I turn on 4v I can not reprogram device anymore in Keil - says Device not found.

4v lines (controlled by P0.05) do not even cross SWCLK or SWDIO lines. What could be the problem?

Device continues to operate properly, just cant do anything with the debugger.

Also eventually after a while i can reprogram the device (after i completely power it off, disconnect JTAG and UART-USB!!!).

Any idea what could be the problem?

Thanks!

[Sergy]

No, its normal for GSM module to have peak current 1.6-2A, they are very short spikes, but that does happen. Not sure why you are surprised? There is no optimization turned on. When I start the debug It stops on main but once I press StepOver first function which is nothing else than setting pin to output and setting it on I get a warning that Processor cant be halted and the whole bunch of register read errors. Please see the screenshot in attachment: Screenshot So it doesnt even go into GSM part it starts behaving weirdly on the first command.