Peavey PC1600X User Manual page 32

7. The value selected here determines how the "pr" bytes will be filled with the parameter value. Refer to your unit's owner's
manual to determine which format to use. For a detailed description of the parameter formats, see Appendix-B.
DEALING WITH CHECKSUM VALUES
Some products call for checksum bytes in their SysEx implementation in order to specify a byte as
checksum, A "cs"' can be added to the string. To program, just edit the byte up to what would normally be
"FC", displayed in its place will be "cs" Here is an example string with an extended display to show you the
entire string:
The PC1600x will compute the checksum as follows:
Adds up all bytes from byte #5 or higher, see below, when FO is byte #0b to the last byte before the "cs."
Note: byte #5 is typically the start of the data portion of the SysEx.
Takes the 2's complement (flips all the bits, then adds 1).
Uses the least significant 7 bits of the result as the checksum byte, The 8th byte is always zero.
With some SysEx messages, the unit ID (byte #3 and command ID byte #4) could be extended beyond a
single byte by using leading zeroes before the non-zero bite, In this case, the PC1600x's checksum
calculation will start later in the string accordingly: at byte #(5 + number of leading zeroes). Note: The "cs"
computation is unavailable in button and set-up strings. In these cases, the checksum must be calculated and
inserted into the string as a constant by the programmer. Be sure and refer to your product owner's manual
for the necessary values/massages.
ASSIGNING STRING DEVICE IDS AND MIDI CHANNELS TO GLOBAL
SETTINGS
Many devices use SysEx command strings that include a MIDI channel or device number as one of the bytes.
This practice is beneficial to the user since it allows separate SysEx control when differentiating one unit
from an identical unit on the same MIDI stream.
Instead of hard coding these values into the strings, a "gc" (global channel) or "dv" (device number) byte
can be designated that references the Global settings in the Utility section. When the PC1600x sees a "gc" in
the string, it will transmit the Utility menu's ChOut setting. When it sees a '"dv" in the string, it will transmit
the DevNum variable:
Additionally, the "gc" designation can be used with MIDI Channel messages. In this case, the "gc" will
channelize the preceding byte, as opposed to being sent as a separate byte. For display, the status and "gc"
bytes are connected by a hyphen to show that they are being combined into a single byte. The following
example is how this would be displayed:
FDR01: Param format
Single Byte
FDR01: String
F0 41 10 70 12 00 00 01 PR CS F7
FDR01: String
F0 00 00 1B gc F7
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Peavey PC1600X User Manual (rev-h)