HOW TO RE-ENABLE JTAG ON LPC21XX DEVICES
Applies to: MCB2140 Evaluation Board
Information in this article applies to:
I mistakenly disabled JTAG communications on my MCB2140 board and
want to re-enable it. I've tried re-programming or erasing flash
using the Philips LPC2000 Flash Utility, but every time I try to
connect I get the message:
Cannot communicate with test board!
My serial connections are correct. How can connect to the device
to re-enable JTAG?
The following low-level flash erase procedure re-enables JTAG for
the MCB2140 evaluation board. This procedure also disables the
- Unplug power from the board.
Make sure jumpers J7, J9 and J10 are
removed and jumper J1 is installed.
Make sure a standard DB9 serial cable is connected from your PC
to COM0 on the board.
- In Windows, start the HyperTerm program.
Set up the HyperTerm connection for 9600 Bits/Second,
8 Bit Data, No Parity, 1 Stop Bit, No
- Apply power to the board.
On the board, press and hold the INT1 button, press and
release the RST button, then release the INT1
In HyperTerm, type the ? character. The word
Type Synchronized, then the Enter key. An OK
Type 12000, then the Enter key. An OK
Type U 23130, then the Enter key. A 0
Type P 0 26, then the Enter key. A 0
Type E 0 26, then the Enter key. A 0
The flash is now erased. You may now debug and download via JTAG
Article last edited on: 2006-11-30 12:05:04
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