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 4-8 Page 25
4.4 Sending Data to the PK-232
Send data to channel 'x' (all modes except Packet assume channel 0) as follows:
SOH $2x (data) ETB
This type of block does not produce an immediate acknowledgement as does a command
block. The data acknowledgement from the PK-232 is sent as a result of a data poll (see be-
low) and produces the following response when the PK-232 can process the data:
SOH $5F X X $00 ETB
If the PK-232 is busy, the response is delayed until the data can be processed. The host
computer should wait for each data ack before sending more data.
4.4.1 Data Polling
The computer can poll the PK-232 for information such as channel data or status, link
messages, data acknowledgements or monitored frames. To poll the PK-232, send the poll
command as follows:
SOH $4F G G ETB
If the PK-232 has nothing to send to the computer, the response is:
SOH $4F G G $00 ETB
If the PK-232 has data to send and information is waiting to be sent, the response is
shown below. Only one block is sent for each poll.
SOH $2F ............... ETB echoed data
SOH $3x ............... ETB data
SOH $3F ............... ETB monitored data
SOH $4x ............... ETB link status
SOH $5x ............... ETB link messages
SOH $5x X X ..... ETB status errors
SOH $5F X X $00 ETB data acknowledgement
Here is an example of the Host mode dialog between the computer and the PK-232:
Computer: SOH $30 (data) ETB data sent
Computer: SOH $4F G G ETB poll
PK-232: SOH $4F G G $00 ETB nothing yet
Computer: SOH $4F G G ETB poll
PK-232: SOH $5F X X $00 data acknowledged
4.4.2 The HPOLL Command
The HPOLL command determines whether the host computer must constantly poll the PK-
232.
o If HPOLL is ON, the host must poll for everything, as described above.
o If HPOLL is OFF, the PK-232 sends all blocks to the host computer when they are
formed and the data poll ($4F G G) is not needed.