Content originally posted in LPCWare by capiman on Sat Nov 29 03:57:54 MST 2014
I have an old dusty KEIL MCB1760 with a LPC1768 on it. During some software experiments
with a new not-yet-well-known software and using JTAG/SWD from uVision V5, the LPC1768 does not answer anymore.
When trying to download software I get "Cannot access memory". Same when trying to erase the chip.
I tried to use FlashMagic/lpc21isp, but both cannot access the LPC1768.
FlashMagic reports problem with autobauding, lpc21isp gets no sync.
I already pressed INT0 button and the pressed/released RESET button, to try to come into bootloader.
I think there was no CRP enabled. I had flashed the same program a few times before,
till it was suddenly not more possible to flash.
I already measured voltages, used different cables, but all no success.
I used a oscilloskop and see RSTOUT is toggling, a small LOW signal every 1,5 ms.
Looks like the LPC1768 is resetting itself again and again.
Reset (in) is only changed when RESET button is pressed.
Also external 12 MHz oscillator is not running, pin 22 stays Z, pin 23 stays GND.
Someone an idea what can help beside exchanging the chip?
