AEA PAKRATT PK-232, Technical Reference Manual

Page: 20 / 101

PK-232 TECHNICAL MANUAL CHAPTER 4 – HOST MODE AND SPECIAL APPLICATIONS
PK232TM Rev. A 5/87 4-3 Page 20
o Next come the literal command or data characters.
o Each block end with $17 or ^W, the ETB (End of Transmission Block) character.
Therefore, in Host mode, each block appears as follows:
[SOH] [CTL] [data] [ETB]
In addition, DLE (Data Link Escape), $10 may be used as a pass character.
o If one of the data field characters is SOH ($01), DLE ($10) or ETB ($17), the pass
character DLE ($10) is inserted before the data character.
For example, data consisting of the bytes $04, $01, $05, $10, $12 is sent to channel 0 in
this block:
$01 $20 $04 $10 $01 $05 $10 $10 $12 $17
SOH CTL data DLE data data DLE data data ETB
This occurs in either direction, from the computer to the PK-232 or from the PK-232 to the
computer.
4.1.6 Host Mode Recovery
If it becomes necessary to quit Host mode because of a problem on the RS-232 link, send
any command, with TWO SOH characters to start the block. This makes sure the PK-232
goes to a known state where it is processing commands. A suggestion:
$01 $01 $4F $47 $47 $17
SOH SOH O G G ETB
4.2 Host Computer Commands
The host computer send blocks to the PK-232 using the CTL bytes:
$2x: Data to channel x, where x = 0-9
$4x: Command to channel x
$4F: Command, no change to input channel
The computer sends commands to the PK-232 in the following format:
SOH $4F
a b
(any data) ETB
where
a
and
b
are the two character Host mode mnemonic or abbreviation for that com-
mand.
o When setting a parameter, do not send the SPACE character between the command
and the first argument.
o Arguments are entered just as in the verbose mode, with space characters or com-
mas between arguments.
o The command ends with ETB, without a carriage return before it.