SMPTE Machine MIDI protocol
The MIDI protocol always follows this pattern (all bytes shown in hex):
Byte 1: F0
Byte 2: 7F
Byte 3: 7F
Byte 4: 02
Byte 5: 7F
Byte 6: command opcode (15, 16, 17, or 18 ONLY)
Byte 7: F7
or this pattern for Force SMPTE Time:
Byte 1: F0
Byte 2: 7F
Byte 3: 7F
Byte 4: 02
Byte 5: 7F
Byte 6: command opcode (19 ONLY)
Byte 7: HOURS tens digit
Byte 8: HOURS ones digit
Byte 9: 00
Byte 10: MINUTES tens digit
Byte 11: MINUTES ones digit
Byte 12: 00
Byte 13: SECONDS tens digit
Byte 14: SECONDS ones digit
Byte 15: 00
Byte 16: FRAMES tens digit
Byte 17: FRAMES ones digit
Byte 18: F7
Command opcode 15 = start SMPTE
Command opcode 16 = pause SMPTE
Command opcode 17 = reset SMPTE
Command opcode 18 = idle SMPTE
Command opcode 19 = force SMPTE time
Every "digit" is an ASCII character "0" through "9", which means the byte is
hexadecimal 30 through 39.
Important Notes:
Be sure to use Winscript.ext to configure your SMPTE Machine to accept MIDI protocol, set the
SMPTE frame rate, and set the Start, Stop/Loop times by using the window under the
Configuration|SMPTE menu.
To configure the electrical interface for MIDI, set jumpers W2 and W3 on the SMPTE Machine
PCB card to the “MIDI” position. In this position, W2 selects a 31250 baud rate (standard MIDI
rate) and W3 selects the MIDI serial buffers and MIDI connectors.
To configure the electrical interface for RS-232 operation, set jumpers W2 and W3 on the
SMPTE Machine PCB card to the “RS-232” position. In this position, W3 selects a 38400 baud
rate and W3 selects the RS-232 serial buffers and DB9 connecctors.
Examples (preceding “h” indicates a hex number):
Start SMPTE: hf0 h7f h7f h02 h7f h15 hf7
Idle SMPTE: hf0 h7f h7f h02 h7f h16 hf7
Reset SMPTE: hf0 h7f h7f h02 h7f h17 hf7
Pause SMPTE: hf0 h7f h7f h02 h7f h18 hf7
Force SMPTE: hf0 h7f h7f h02 h7f h19 h30 h31 h00 h32 h33 h00 h34 h35 h00 h30 h30 hf7
(forces SMPTE timecode to 01:23:45:00)
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