Tektronix 77807-1, User Manual

Page: 72 / 132

Appendix B: Remote Control
DS1000 Series User Manual
B–9
DS1000 > [DLE] [STX] [Ad] [Arr] [DLE] [ETX]
Data phase
The PC continuously polls the television demodulator.
PC > [DLE] [ENQ] [Ad] [Ars]
Send Addressing phase
DS1000 > [DLE] [ACKO] [Ad] [Ars]
Ready phase
PC > [DLE] [STX] ['PATH?'] [DLE] [ETX]
Data phase
PC > [DLE] [ENQ] [Ad] [Arr]
Receive Addressing phase
The television demodulator responds with data when it has a message.
The [data] is the path, Ad Ars, which indicates that a message is
available from the responding television demodulator.
DS1000 >[DLE] [STX] [Ad] [Arr] [data] [DLE] [ETX]
Data phase
Getting a Message
Polling a television demodulator only tells the PC if a message is
available. To receive the message, you must use the MSG? command.
The following example shows how to use the MSG? command to
retrieve a status message from a television demodulator.
The PC addresses a television demodulator that is busy and repeats the
addressing phase until the television demodulator returns a ready
phase. The PC then sends the “MSG?” command.
PC >[DLE] [ENQ] [Ad] [Ars]
Send Addressing phase
DS1000 > [DLE] [ACKO] [Ad] [Ars]
Ready phase
PC > [DLE] [STX] ['MSG?'] [DLE] [ETX]
Data phase
After receiving the MSG? command, the television demodulator
places its answer in its transmit buffer, and the PC retrieves the
message with a receive phase. The data in this example (20h) is the
test message. Other bit patterns are listed with the MSG? command.
PC > [DLE] [ENQ] [Ad] [Arr]
Receiving addressing phase
DS1000 > [DLE] [STX] [Ad] [Arr] [20h] [DLE] [ETX]
Data phase
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