I use the LPC2294, make a project with ARTX and use the ULink to debug. In the Startup.s, the default VPB Clock=CPU Clock/4, when I change it to 'VPB Clock=CPU Clock', then the problem come. After I push the button of 'Start/Stop Debug session' the program load to the flash and get the error 'Couldn't stop ARM device! Please check the JTAG cable'. But After I erase the 2294, I set the 'VPB Clock=CPU Clock/4' and Debug again, no such problem. So I want to know whether the ARTX support 'VPB Clock=CPU Clock'? Or the Ulink don't support 'VPB Clock=CPU Clock' whe use the ARTX?
But if I don't use the ARTX, the debug is OK. I can set 'VPB=CPU Clock' or 'VPB Clock=CPU Clock/2' in the Startup.s. Or I can just set 'VPBDIV=1' or 'VPBDIV=2' in the main function. But when I use the ARTX, the VPB should equal to CPU Clock/4, not equal to CPU Clock or CPU Clock/2, also never set 'VPBDIV=1' or 'VPBDIV=2' in the main function or the task function, otherwise the error 'Couldn't stop ARM device! Please check the JTAG cable' come into being. So I think that the device has no limitations regarding VPB clock but the problem of ARTX. Another instance is after the error come I must use the series(UART0) to erase the chip, otherwise I can not load the program to the chip by the Ulink.
I doubt that this problem refers to ARTX. But if so, that means if we choose ARTX the VPB clock must be CPU clock/4, not more and not less? Can keil fix this problem?