Manual

Detailed Descriptions of ACL Commands 3-15
All front panel buttons work normally during the execution of a Download Sequence. For
example, PAUSE causes execution to be suspended until PAUSE is pressed again; STOP
causes all motion to cease until a CS command is executed. Any ACL output commands
(e.g. OA, OC, OS) send their outputs to the host, as usual. (Of course, if no host is
connected, the outputs go into the "bit bucket".) ACL errors in the downloaded commands
are logged as usual. When the erroneous command is executed the System immediately
sends a "?" to the host. (Some errors are caught during downloading and thus do not occur
while the sequence is executing. See the Storage section, later in the chapter.)
Repeating
<rept> is the repetition count, an integer in the range 0 through 65535. It is optional but
cannot be specified unless <id> is also specified. If <rept> is omitted or has the value 1 the
download sequence executes once each time it is invoked. If <rept> is greater than one the
sequence executes the specified number of times. If <rept> is zero the sequence repeats
forever until the power is turned off or the machine is reset, or
ESC.!5: is sent from the host.
The BD command's <rept> parameter can be overridden by the XD, XU, and XW
commands.
External Control
Escape sequences (see Chapter 6) cannot be stored as part of a Download Sequence. If an
escape sequence is received while the System is either in Downloading mode or is executing
a Download Sequence, the escape sequence is executed immediately.
If ACL commands are received from the host while a Download Sequence is executing they
are stored in the input buffer and are executed upon completion of the Download Sequence.
If the Download Sequence is repeating infinitely the ACL commands will never be executed,
unless the Download Sequence is halted.
The execution of a Download Sequence can be prematurely halted four ways: by resetting
the machine or turning off the power; by executing an AD command which is contained in
the Download Sequence; by sending the
ESC.!5: command (see Chapter 6); or by exceeding
the maximum nesting depth (see the XD command).
Storage
In the 16K non-volatile memory 13894 bytes are available for the storage of Download
Sequences. The rest of the 16K bytes is consumed by overhead, by the personality
parameters, by the XY Linearity Correction Table, and by the ACL variables.
The available download memory can be divided in any proportion between the Download
Sequences, as long as the total space used does not exceed the amount available. If this
happens an error is logged and any further ACL commands are ignored, up until the next ED
command.