Appendix - Recover The Locked Device - Nuvoton ISD-DEMO15100 User Manual

These operations do not have to follow a special order. USB dongle is hot pluggable, and so is the demo
board. However, during digital programming, demo board needs to be connected otherwise the
integrity of flash image cannot be guaranteed.
User can refer VPE user manual for the operation guide. VPE user manual can be found in VPE
installation folder; i.e. usually it is under: C:\program files\ISD-VPE15100.
Appendix –
Due to the nature of ISD15100 series device, sometimes the device may get itself locked. The symptom
of lockup is that device stops to respond. For example, under VPE GUI, after power on device status
cannot be read, i.e. the device is always Power Down. On customer's target board, device can no longer
be powered up and it also stays at Power Down mode. In short, device appears to be "dead".
Often device Lock up is caused by "bad" memory content. Here are some examples in which device will
get locked.
- In POI VM there is a command to set device to the external crystal as the clock source, but
hardware wise there is no external crystal soldered, then this device will lock up after power on.
- In POI VM if user chooses to loop play a sound effect forever, then this device will fall to respond
to outside after power on;
- Due to any unpredictable reason – such as a glitch during flash programming, the device
memory content is not intact and it causes device Power On or Power Up failure.
For these lockups caused by "bad" flash image, there is a way to recover the device without hardware fix.
Steps to unlock ISD-DEMO15100 board
- Without powering the board, pull down the ISD15100 pin 28 to ground, i.e. install jumper J14.
- Power the board – connect USB cable,
- Launch ISD-VPE15100, send power-up command and wait till power-up finishes.
- Leave the ISD15100 pin 28 floating, i.e. remove jumper J14.
- Chip-erase the ISD151xx.
ISD-DEMO15100/15C00/3900
Recover the locked device
Publication Release Date: Feb 08, 2011
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