Sorry for the late reply, I do not visit this group often.
--- In email@example.com, "pbutterworth1967" <paul@...> wrote:
> I work with a product thats based on a LPC2138 processor. It requires
> you to send a string to the device to put it into ISP mode.
A few years back, I implemented something similar in lpc21isp, and it
is still there in version 1.63. My device (also based on an LPC2138)
responds to the '?' (just like the LPC2000 bootloader), but its
response is different from that of the LPC2000 bootloader. But
probably, my code is not very relevant for your requirements.
In the file lpcprog.c, search for the line
"SendComPort(IspEnvironment, "?");". In your case, you need to modify
lpcprog.c to send a different text (than the '?').