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LexiconPCM 80 Version 1.10 MIDI Implementation Details
Data Dumps A dump contains information about some aspect of the PCM 80’s internal state. A dump
is transmitted by a PCM 80, eitheron request to another device, or to another PCM 80
(via front panel dump commands or SysEx Automation). When a dump is transmitted
to a PCM 80, it will normally cause a change in the internal state of the PCM 80. A dump
can also be purely informational, containing version information, etc. This sort of dump
may be received by a PCM 80 but results in no change. It is initiated only as the result
of an external request and may be considered as unidirectional.
Enabling System Exclusive Messages
The PCM 80 must be enabled via the front panel controls for receipt of System Exclusive messages. If
System Exclusive message receipt is not enabled, all System Exclusive messages are ignored. The
status of both the PCM 80 Memory Protect function and PCM 80 Pro and Go Edit modes are ignored when
System Exclusive is enabled.
ASCII Character Data
Many of the System Exclusive messages include ASCII character data. This refers to the values between
0x20 (space) and 0x7E (tilde). No other values should be used. Character fields should be padded with
spaces — the C NULL-terminator should not be used. When the PCM 80 receives an out-of-range value,
it will convert that value to a space. The small block character on the PCM 80 display (used to indicate
patch source/destination) is transmitted as a tilde. It is not possible to transmit this character to the PCM
80 via System Exclusive messages. The ASCII backslash character (0x5c) maps to the yen character
(¥)on the PCM 80 display.
Numeric Values
Any numeric values greater than one byte are transmitted from least-significant to most-significant.
Nibble-ized data
Some data (most importantly effect data) is transmitted in a nibble-ized format, i.e. each byte of data is
transmitted as a pair of bytes, with 4 bits of data in each byte. As in all other cases in the PCM 80, the less-
significant portion of the byte is transmitted first.
Data Errors
The PCM 80 will display System Exclusive errors when it encounters any of a number of problems,
including checksum errors and early termination of a System Exclusive message (too few characters).
It will also report back to the sender of a System Exclusive message if it cannot fulfill a legally formatted
request. This covers situations such as bank-not-present, etc.
Timing Considerations
As some messages require significant time to process, System Exclusive information should not be sent
to the PCM 80 in bursts of more than 3 messages every 20ms. The individual message descriptions
presented later in this document note any specific time out requirements.
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