ADVANCED MICRO SYSTEMS, INC. | SERIAL INTERFACE |
Anatomy of Instruction Execution
This information is intended to familiarize the programmer with the internal operations involved in executing a command.
For each MOTION command there are four cycles; Entry, Execution, Result, and Completion. Other commands have three cycles; Entry, Execution and Result. In the idle state the controller continually tests for jog, go, or command input. The following describes each operation that takes place on receipt of a command.
Cycle 1: Entry
A. Serial command and data information is placed in a command line buffer as received. Editing is permitted in SINGLE axis mode. ESCape aborts operation and returns to idle state. A carriage RETURN (Line Feed for Daisy Chain) terminates the entry cycle and initiates execution.
Cycle 2: Execution
The command is processed. In the case of two consecutive action commands, execution will be delayed until any previous completion cycle has been completed.
Cycle 3: Result
The result cycle outputs any numerical result required by the command, i.e., the position. The result type is signed numerical data, preceded by space padding and followed by a Carriage Return and Line Feed. If the result does NOT produce numeric data then the Carriage Return, Line Feed output indicates execution is complete.
Cycle 4. Completion
The completion phase is required for any Action command cycle.
The following are Action commands:
Action Command | Completion Cycle |
|
|
GO | Until last instruction is complete |
Step Resolution | Until previous action complete |
Constant Speed | Until previous ramp is complete |
Find Home | Until home is found |
Relative Move | Until full index is complete |
+Step Index | Until full index is complete |
- Step Index | Until full index is comp lete |
During the completion cycle (except for “GO”), any
The controller has the capability to “queue up” another action command during the completion cycle resulting from a preceding action command. The execution and result cycle of this “Pending” command is delayed until the completion phase is complete. This interval is called the PENDING PERIOD. During this PENDING PERIOD, the only input accepted is the one character interrupt (abort) command, limit switches, soft stop input and hard stop (ESCape).
External indication of PENDING PERIOD end, execution and result cycle of the pending instruction is the carriage RETURN or Line Feed in the party line mode. The GO command is regarded as a command that has a continuous pending (Instructions Queued) period.
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