Posts by doerity

I have been having problems using a J-Link ARM and connecting to a LPC2138 on custom hardware. See previous post ([ANSWERED]Connecting to LPC2138 w/ J-Link ARM Pro) for details. However I have found the solution to this problem. The LPC2138 JTAG pins can be multiplexed with GPIO pins. After reset the LPC2138 will sample the RTCK pin and if this is low the JTAG pins will be used as JTAG, otherwise they will be used as GPIO pins. I'm not sure if the reset strategy in software can account for this by bring RTCK low while releasing the device from reset of if there needs to be documentation added that a pull down is needed for this pin.

I have tried using the new software and I am still having the same problems.

As well I am able to read all the memory correctly with JMem.

The end goal is for me to be able to connect and debug code running out of flash on the LPC2138 with Rowley CrossStudio. I am first trying to connect to the target board with the the JLink.exe command line program. When first opening the program it is about the read and detect the device.

Screen Shot:
[Blocked Image: http://www.segger2.com/index.php?page=Attachment&attachmentID=44&h=f720fbc6513fa94b13f31fa49bffa10a7b681839]

How ever when I type "r" to reset, it works the first time, "I think":

Screen Shot:
[Blocked Image: http://www.segger2.com/index.php?page=Attachment&attachmentID=45&h=4da5cdb67da400ec594cd65abcd8131d07907c2c] Then when I type "r" again, it doesn't seen to be able to connect.

Screen Shot:
[Blocked Image: http://www.segger2.com/index.php?page=Attachment&attachmentID=46&h=197a3624ed4f3e4af8bb6f133ff2910f0d1dbcb1] And when I try to connect with CrossStudio is tells me Could not find supported CPU core on JTAG chain, Failed to connect, or when I try to connect with J-Flash ARM, I get either a;
Failed to download RAMCode for CPU clock frequency detection!
Failed to measure CPU clock frequency
Fail to connect
or
Could not find supported CPU core on JTAG chain
Failed to connect.

Any Ideas what what I can do to trouble shoot. I am using the LPC2138.jflash project and V4.10f

Thanks

Tyler

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