Flash download error when in deep power down mode

 Flash download error when in deep power down mode

I have programmed an LPC1768 to be nearly always in deep power down mode. It is waken periodically by an RTC alarm

Since I did this, I cannot reprogram the processor using the programmer included in Keil's microcontroller development tool kit.

What is the solution ?

Best regards

 RE: Flash download error when in deep power down mode

Some more information :
programmer/debugger's name is U-LINK ME

Error message is : "Error: Flash download failed - Target DLL has been cancelled"

The processor runs its program normally from what can be seen with an oscilloscope.

 RE: Flash download error when in deep power down mode

maybe you can hold the processor in reset using an external pin, release it (or not...?) and quickly erase the flash using JTAG/uv4...?

 RE: Flash download error when in deep power down mode

Thanks, but, it does not work

 RE: deep power down mode

I guess the debugger cannot distinguish beween the target being disconnected, and the target being "in deep power down mode"?

Have you spoken to Keil support about this?

Have you spoken to NXP support about this?

 RE: deep power down mode

Question to keil in process

 RE: deep power down mode

Debugging is not possible in Power Down mode on LPC17xx because the chip turns off also the debug interface. Therefore also flashing is not possible.

A simple solution is to force the chip into bootloader mode at reset by holding EINT0 low while resetting the chip. Since chip will stay in bootloader mode the application which uses power down won't be executed and it will be possible to erase/reprogram flash.

 RE: deep power down mode

Thanks for the EINT0 idea.
As a matter of fact, I had included some code to run a loop when coming out of deep power down if a pin was 0V.It works, I can see it on scope.
I also can enter debug mode. Just cannot reprogram the flash : I get : "SWD communication failure" and then "Flash download failed"

 RE: deep power down mode

Have you forced the chip into bootloader mode and then tried to erase the flash?

 RE: deep power down mode

No, The pin is connected to its neighbour VddIO. So it is quite difficult to cut the connection temporarily. It is nearly as difficult as changing the micro.

 RE: deep power down mode

Pb solved.
After disoldering the NMI pin to add a pull up to Vdd and force it to Gnd at reset, I have been able to reprogram the uc.

Thanks for your help