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Unstable JTAG connection to custom board with ADSP-21489

Question asked by adrianpang on Feb 13, 2013
Latest reply on Mar 21, 2013 by adrianpang

Hi all,

 

I am having some problems with a custom board that is based on ADSP-21489. I have been able to use USB-ICE to communicate with the DSP on the custom board for quite a number of days. However, recently I keep getting the following errors in both VisualDSP as well as CrossCore Embedded Studio:

 


Unable to halt processor. JTAG communication failed.

You may need to exit the debugger and reset the target hardware to correct this problem.

 

If I choose Do Not Disturb instead of Halt Then Reset in the USB-ICE device properties, I see that the processor is "Running" but when I halt or reset the core manually I get these messages:

 


JTAG scan failed - Check target power and emulator connection.

JTAG scan failed - Check target power and emulator connection.

Failed first NOP block scan.

JTAG scan failed - Check target power and emulator connection.

Failed second NOP block scan.

JTAG scan failed - Check target power and emulator connection.

JTAG scan failed - Check target power and emulator connection.

JTAG scan failed - Check target power and emulator connection.

DSP could not generate emulator interrupt

JTAG scan failed - Check target power and emulator connection.

 

I am using an external oscillator as well as ADM809 supervisory IC to ensure RESET is low for at least 240ms at power up.

 

Since I have established JTAG connection with the DSP on the custom board before, the JTAG connection should be OK.

 

Any ideas on where to start troubleshooting will be helpful.

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