[sudo-discuss] robot reading a file from disk - serial conversation eavesdropping

[Jake]

the robot has an external disk drive which is connected to it with a 
25-pin serial cable.  The disk drive unit is a computer in itself, with a 
lot of functionality.  It boots up in "ERC MODE" meaning it's ready to 
talk to the YASNAC ERC, our robot control computer.

i spied on the conversation between the robot and the disk drive while the 
robot loaded a file.  I saved the conversation using the salae logic 
program:

https://www.saleae.com/downloads

if you run this program you can open the save file i saved:

http://spaz.org/~jake/robot/floppy-loadafile.logicdata

you will see that the format matches closely that which is described by 
the communications manual:

http://spaz.org/~jake/robot/479236-17-Communications.pdf

the baud rate is 4800 baud, 8 data bits, 1 stop bit, EVEN parity.

it's connected to the 3d printer computer if you want to write a program 
to pretend to be a disk drive.  then we can send it programs without 
having to use ancient floppy diskettes.

to talk to it from that computer (whose IP address is .42.8) just run a 
script called "robot" in ~sudodesk/bin/robot
it calls screen /dev/ttyS0 4800,parenb,-parodd
(that's how you get even parity with screen)

when i open that terminal, and then go to the floppy menu from the robot, 
it sends the following (? means unprintable character):
ENQ?ENQ?ENQ?CAN+?CAN+?CAN+?EOT?

which means, probably; HEY ARE YOU THERE?
HEY ARE YOU THERE?
HEY ARE YOU THERE?
NEVER MIND.
NEVER MIND.
NEVER MIND.
I'M HANGING UP NOW.

see if you can get the robot to load a file from an imaginary disk drive.

-jake