Security bits lpc93x

[Hans Wiermans]

Hello,

We programm lpc93x boards  with flash magic. Settings: erase all flash, protect isp-code,  no unused flash fill, no crc, no security bits. While programming the boards sometimes security bits get set. Does anyone know the reason or has the same experience?

[Andy Ayre]

After most ISP operations the security bits are read, and if set then the corresponding checkboxes will be checked to show this. If you are not erasing the security bits but you are unchecking the boxes, then they will keep getting checked afterwards. Coud this be what you are seeing?
Does this happen intermittently? If so how often? Which security bits get set? The same ones each time or does it appear random?

[Hans Wiermans]

Hello Andy,

Thanks for the quick response. Cause we start with erasing all flash and not setting the security bits in the flash-tool, the security bits in the device should be cleared while erasing the flash. Somehow the bits get set after programming, read back by the flash-tool and get set in the check-boxes and the next devices will be programmed with the same bits on.

i dont' have exact numbers how often it happens, our manufacturer pays some more attention to it so this will come. In the devices which i've tested afterwards bit 0 in block 0 and bit 0 in block 6 six were set.

Kind regards,
Hans Wiermans

[Andy Ayre]

Try this:

Start Flash Magic
Press F1 to enter debug mode ([Debug] appears at the top of the window)
Read the security bits to demonstrate they are unset
Erase all flash and program.
Read the security bits to demonstrate they are now set
Press F2 to end debug mode
Email me the generated debug file C:\flashmagic.fmd

My email address is at the bottom of this post.