Grass Valley 2200 - Manual (Page 67)

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Data Transfer (5E and DE) Commands
Transfer Command Examples
Data transfers occur as a dialog between the editor and the switcher. One side acts
as the transmitter of the data and the other as the receiver.
An editor always initiates a transfer; it acts as either the transmitter or the receiver
of data depending on the direction of the transfer. A dialog proceeds as the
transmitter and receiver send messages back and forth to each other requesting
and sending data. Even though the editor always initiates the transfer, it is the
receiver that is in charge of pacing the transfer because it speciÞes the sequence
number of the next packet it expects the transmitter to send in the request
message. So if the receiver detects an error it can abort the transfer, or ask for a
retry by repeating a request for the same sequence number again. (See Error
Detection and Handling, later in this section).
The following examples show scenarios of editor-to-switcher command dialogue
that demonstrates how the Transfer commands work.
Scenario 1
The editor is going to read Register Number 33 (21H) from Mix/Effects 1. The
editor is the receiver of the E-MEM data. The register it is going to receive contains
1450 bytes of data. The following dialogue is the result:
1. The editor sends a request to the switcher:
2. The switcher sends the first block of 250 bytes of data to the editor:
3. The editor sends a request for the next block to the switcher:
4. The switcher sends another 250 bytes of data to the editor:
Byte
Count Effects
Address Command
Code Sequence
Number Register
Number E-MEM
Data
05 01 5EH 00H 00H 21H none
Byte
Count Effects
Address Command
Code Sequence
Number Register
Number E-MEM
Data
FFH 01 DEH 00H 00H 21H 250 Bytes of E-MEM data
Byte
Count Effects
Address Command
Code Sequence
Number Register
Number E-MEM
Data
05 01 5EH 00H 01H 21H none
Byte
Count Effects
Address Command
Code Sequence
Number Register
Number E-MEM
Data
FFH 01 DEH 00H 01H 21H 250 bytes of E-MEM data