Sequential Prophet VS - Page 106

106
Byte Description Range Examples/notes
Dump Data Packet
ii channel number (00-0F)
jj packet number 00 -7F Running packet count. Starts at 00,
(equals 60 words) increments with each new
packet. After
7F, resets to 00.
kk xl20 120 bytes of actual sample.
(equals 60 words)
Each MIDI byte holds seven bits. Therefore two bytes are
required to transmit a twelve-bit Prophet VS sample word. Words
are sent left-justied, MSbyte rst, unused bits reset to 0: Oxxx
xxxx Oxxx xxOO.
The nal packet still contains 120 bytes, regardless of how many
signicant bytes actually remain. Unused bytes in the packet are
lled out with zeroes.
ll checksum 00 - 7F
The checksum is is an Exclusive-OR of the previous 120 data
bytes.
The master dumps the data packet under one of two conditions:
1) in the closed-loop system, receiving an Acknowledge
message, or 2) in the open-loop system, receiving nothing for two
seconds after sending the header.
After sending the data packet, the master waits for 20
milliseconds while checking MIDI IN. If a Not Acknowledge is
received, it resends the previous packet. If Acknowledge is
received, it immideatiely starts sending the next packet. If nothing
is received within this period, it assumes open-loop conditions,
proceeds as if an Acknowledge were received. Namely, it
increments the packet number and sends the next packet.
(F7) End of Exclusive
After successful transmission of the nal packet, and the nal
handshake (if closed loop), the master transmits an F7, and both
machines go back to normal operation.
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