APOPAP wrote on 2025-03-25, 08:47:
Thank you! For bootstrap, can a null modem cable(3wires) be used?
This is all covered in the DDLINK documentation and interactive help,
including wireing diagrams for required cables.
DDLINK itself only needs a 3-wire NULL-MODEM cable (RxD, TxD and Gnd)
but ... for /Bootstrap, it has to "talk to" DOS which demands a
7-wire cable (RxD, TxD, Cts, Rts, Dtr, Dsr and Gnd)
btw, /Bootstrap works by:
you enter "CTTY COMx" on target system
DDLINK sees DOS prompt on serial port of local system, and performs:
> COPY COMx DDLINK.COM
.. send small bootloader
COPY ends with ASCII EOF character 0x1A (so bootloader code
can't contain 0x1A ... this works well on MSDOS and PCDOS which
write ANY other byte to the file (almost binary), however FREEDOS
blocks more bytes - fortunately I was able to find a byte I could
XOR the bootloader code with which avoids the blocked bytes
(at least for now ... in the version of FREEDOS that I tested)
> DDLINK.COM <- Execute the initial bootloader
.. perform much better/safer transfer of actual DDLINK.COM
code which is written back to DDLINK.COM
> CTTY CON
At this point DDLINK.COM is now on your target system, and you
can use it to move more files.
Dave ::: https://dunfield.themindfactory.com ::: "Daves Old Computers"->Personal