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i have changed the PLL setting in the start up code as per the below listing.
PLL Constants original value changed value PLLCFG_Val EQU 0x0000000B 0x00010027 CCLKCFG_Val EQU 0x00000004 0x00000007 USBCLKCFG_Val EQU 0x00000005 0x0000000A
in this case the FCCO value is 288 MHz in previous case and i have changed it to 480MHz and cclk i have changed to 60 Mhz from 57.6 MHz ( as in user manual it is mentioned that 480MHz is the minimum possible value for Fcco if u want to use both USB and UART)
and the main loop code is
int delay; PINSEL4&=0XFFFFFF00; FIO2MASK=0XFFFFFF00; FIO2DIR0=0XFF; while(1) { FIO2SET|=0X000000FF; // OFF LED's for(delay=0X00FFFFFF; delay--;); FIO2CLR|=0X00000000; // ON LED's }
after downloading the code the JTAG was not able to enter into the debugging session. when i have checked for the Debug device chain window i found that there is no Device ID .
i have tried with flash magic to erase the controller by using a serial cable ( with jumpers J4 and J13 removed ) when i tried to read the devise signature it was not able to read and hence i was not able to erase the controller either.
please try to suggest me what is the root cause of the problem. what is the problem with the pll settings? i have not changed any thing in pll settings appart from changing of the 3 constants( as specifeid on top) in the startup code generated by the KIEL Uv3.
@Franc Urbanc
Thanks for the reply, which option should i select for the erasing?( either JTAG or UART ? in the utilities tab of otions for target window ) if UART/JTAG what are the necessary jumper configurations? . i have tried with JTAG with J4 and J13 jumpers ON a "Not able to detect JTAG device " error message is beeing prompted. shall i try it with UART please suggest the required environment/jumper settings also.
Use a JTAG. Try several times. It is important that uVision gets control over the target before the PLL settings are changed.
Erase the chip using FlashMagic via the COM interface. See:
www.keil.com/.../mcb2300_fp_flash_utility.htm
@ Franc Urbanc
I have tried several times according to the procedure suggested, but it is repeadly giving the same error " No JTAG devices found" i have pressed reset button on board while clicking on erase flash option. even though the reset pin is level sensitive i have tried with different press and release times. the device ID of the JTAG on the board(controller) was not beeing read/identified.(checked in the settings of debug tab in options window)
@ Reinhard Keil
i have already tried this option as the board distributor suggested to do so. but the flash magic utility was not able to read the device signature. and it is promting a message stating that access of device through wrong protocol may leave the device unusable. i have connected a standard serial cable ( came with a Digital Storage Oscilloscope for connectivity with pc fron end). the environment & jumper settings are as per the link. i have selected com1 in the settings of flash magic and tried with both com0 and com1 on board. please suggest some solution to reactivate the board
Maybe this will help:
www.keil.com/.../mcb2300_fp_flash_alone.htm
i have already tried this option. my evaluation board distributor has suggested this solution. but the Flash magic was not able to read the device signature. can we solve this in any other way?