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Potential flash damage?

Question asked by Brook Matheson on Sep 3, 2016
Latest reply on Sep 6, 2016 by jeremyzhou

Hi I have created some PCBs based around the LPC1769, 10 of these boards have been assembled at an assembly house of which only 2 function.

I am programming these boards with a working bootloader program via flash magic, to get the lpc1769 into isp mode I pull pin 2.10 to ground as it is pulled high with a 10k resistor as well as reset. This allows the chip to enter into ispboot mode allowing communication via uart0, this has worked for 2 of the boards allowing the bootloader code to be programmed and they have functioned correctly.

With the other 8 boards imediately on power up the lpc1769 enters isp boot mode without pin 2.10 being pulled to ground, I have checked this pin with my oscilloscope and can see it is high the entire time. I have also checked the individual supply inputs and they are all receiving a clean 3.3v supply?

So I can connect to flash magic and read the flash memory for these 8 boards, which has FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF value for all the sections.

After programming the bootloaader I cannot reset the lpc1769 and if I look at the flash memory I have the same value for all sections, so the program hasn't been stored in the flash.

Could this be caused by damage to the flash during the reflow solder process?

Any ideas to what might be causing this would be awesome,

cheers.

 

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