360 Systems DigiCart/E - Manual (Page 81)

Serial Control Protocols • • • • 71
Peripheral Bus
This section covers a general description of the Grass Valley switcher Peripheral Bus II protocol
implementation on DigiCarts. The commands are ASCII strings terminated with a carriage return. All data
values are represented as hex ASCII digits. Data field widths are fixed, thus all digits must be supplied. No
intervening white space is required and any found will be ignored.
If a line error or line break is detected, the input queue is cleared. Invalid commands are ignored.
The following commands are recognized:
Command Description
L bbbbbb rrr Learn (save current cut number to a register)
R bbbbbb rrr Recall (select cut saved in a register)
T bbbbbb f Trigger (see below)
Q dd Query (respond with "QDIGICART\r")
C dd Clear All registers in DigiCart at address dd
Where:
bbbbbb Six hex digits which represent a 24-bit binary device address list (actually a bit map
array). Each bit represents one of 24 devices that should respond to this command
if the bit is set. Setting multiple bits will trigger multiple devices. This corresponds
to the DigiCart/E Remote Control Address setting. (Some PBUS devices start
numbering at 0, in which case 0=Digicart Address 1, 1=2, etc.
rrr Three hex digits indicating the learn/recall register number on the DigiCart which
holds learned cut numbers. The DigiCart supports 128 register numbers (0x00
through 0x7f). Register values outside this range are ignored.
f Single hex digit identifying the trigger function to be performed:
Grass Valley [PBUS – (GV)] Sony [PBUS – (SONY)]
0 = Play 0 = Stop
1 = Stop 1 = Play
2 = ignored 2 = ignored
3 = Loop 3 = ignored
4 = Pause On 4 = Stop
5 = Pause Off 5 = Pause On
6 = ignored 6 = Pause Off
7-F = Play 9 = Play
dd Two hex digits indicating one of 24 peripheral device numbers (0x00 through
0x17). 0x00 is ignored, addressing begins at 0x01 for DigiCart remote address = 1.
The SET AUX PROTOCOL setting in the Setup Menu determines whether Grass Valley or Sony trigger
function codes are used. Complete protocol documentation is available from Grass Valley Group and Sony.
H ARDWARE F ORMAT
The serial connection is a 4-wire EIA-485 (RS-485) full-duplex channel. EIA-485 is a multi-drop version
of the EIA-422 specification, and is fully compatible. Baud rate is 38400.
D ATA F ORMAT
The data format follows the Peripheral Bus specification in that the data transfer is asynchronous, 8 bits per
byte, 1 start and 1 stop bit. GV format uses even parity, Sony format uses odd parity.