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LI0083 – Revision 22 June 2017
The 12AU Behavior and Protocol Specification
Interface and Protocol Specification
Compatibility
The 12AU protocol specification complies with the 12AP specification version 1.2, where appli-
cable. (The Floating command is omitted).
USB Interface
There is no flow control/handshaking; therefore commands must be sent one by one, waiting for
the response.
The input buffer is 64 bytes, in case of overflow a response: “Buffer overflow” will be submitted.
This will not happen under normal conditions.
12AU Startup Sequence
After power on or restart, the 12AU immediately initializes the settings of 12AU to current
default settings and turns on all LEDs.
If connected to PC, the OVL leds will be turned off when then USB connection is established,
typically after 4 seconds from power on.
Appoximate after 8 seconds the IRQ and overload system is enabled, the LED will reflect the
setting and a
Reset<crlf>
is submitted.
Behavior
A watchdog is enabled. It will restart 12AU if the processor stops working – this will send the
string
Reset<crlf>
to the host. In this case the host knows that the fault has occurred and will
be able to reinitialise 12AU.
Commands
Note:
<LF>
in input will be ignored, and commands are in uppercase.
