AEA PAKRATT PK-232, Technical Reference Manual

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PK-232 TECHNICAL MANUAL CHAPTER 4 – HOST MODE AND SPECIAL APPLICATIONS
PK232TM Rev. A 5/87 4-2 Page 19
In Host mode, the PK-232 sends data to the computer only when the computer requests
data. This feature is selectable by the user (see HPOLL below).
4.1.3 Entering Host Mode
Enter Host mode by typing the following commands:
Type: AWLEN 8<CR>
PARITY 0<CR>
8BITCONV ON<CR>
RESTART<CR>
Verify that your computer's serial interface driver is also set to eight bits, no parity, and
that you have set your system for hardware control by disabling XON/XOFF and enabling
RTS/CTS/DTR.
Type: HOST ON<CR>
If you wish to apply power to your computer and Host mode immediately, be aware that
power transients may cause random data to be sent to the PK-232.
o To ensure correct entry into Host mode, send XON, CANLINE and COMMAND char-
acters first, as shown below with the hexadecimal representation of each character
listed above each its acronym or literal. Note: 'sp' is the 'space bar' character.
$11 $18 $03 $48 $4F $53 $54 $20 $59 $0D
XON CAN COM H O S T sp Y CR
Follow these steps:
1. Send $01 [^A] (^ = CTRL)
2. Send the sequence: $01 $4F $47 $47 $17
3. If you receive the response: $01 $4F $47 $47 $00 $17
you have successfully entered the Host mode. If you receive some other response, got to
Step 2.
4.1.4 Leaving Host Mode
To leave the Host mode and return to conventional or verbose mode, type:
$01 $4F $48 $4F $4E $17
or ^A O H O N ^W (^ = CTRL)
or transmit a BREAK signal (reversal to SPACE or START polarity of at least 300 millisec-
onds) on the serial link.
4.1.5 The Host Mode Dialog
The host computer and PK-232 communicate in blocks of characters:
o Each block starts with the SOH (Start of Header) character, which is $01 or ^A.
o The next character is a special data-type identification byte, called the CTL (control)
character that indicates whether the following characters are a command, status or
data.