Content originally posted in LPCWare by CodeRedSupport on Tue Apr 27 03:52:39 MST 2010
Quote: g4bch
The original project that caused the problem did try to change the clock speed. I haven't got the exact code here, but from memory it changed the PLL seting something like this.
LPC_SYSCON->SYSPLLCTRL =0x2F ; // 12MHz x 16 / 4 = 48MHz
while (!(LPC_SYSCON->SYSPLLSTAT & 0x01)); /* Wait Until PLL Locked */
The orignal error was that the program gave some sort of memory exception inthe while loop.
It sounds like whatever setting you applied to the PLL/clock has destablized the part. This code is now resident in flash, it executes whenever you apply power to the board. You can approach this problem in two ways. First, set the vector catch option in your LPCXpresso project debug configuration to 'true':
Debug Configurations... -> Project -> Debugger (tab) -> Vector catch (Target configuration)
The LPCXpresso debug will attempt to catch the part out of reset. If this fails, you'll need to boot into the ISP. That is, GND P2.10, and assert RST. Once in the ISP, the target clock configuration is stable, and you should be able to connect. The first thing you'll want to do is restore the previous clock setting so whatever you leave in flash doesn't destablize the part again.
Regards,
CodeRedSupport