Performance Motion Devices PR8358120, Руководство пользователя

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Operation
Prodigy/CME PC/104 User’s Guide
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Signal processing & hardware functions - A substantial portion of the card performs signal conditioning and other
functions associated with safety-related signal processing. These functions are a fixed feature of the card and are not
user-accessible.
Communications functions - The Prodigy/CME PC/104 card provides sophisticated resource addressing
capabilities which allow an external host controller, or the onboard C-Motion Engine, to address various on-card and
card-connected resources. In addition, various direct management features are provided for the Prodigy/CME PC/
104 card’s communication ports (the PC/104 bus, two serial ports, a CANbus port, and an Ethernet port).
Section 2.1.1, “Card Access Basics,” on page 33 provides an introduction to general card access issues that will be
useful while reading the remainder of this chapter.
Section 2.2, “Magellan Motion Processor Functions,” on page 34 through Section 2.7, “Signal Processing and
Hardware Functions,” on page 52 describe each of these specific functional areas.
Section 2.8, “Software Libraries,” on page 54 provides an overview of accessing Prodigy/CME PC/104 card functions
via software libraries.
2.1.1 Card Access Basics
The Prodigy/CME PC/104 card functions as a bus master for the PC/104 bus. It can communicate to PMD-based
slave cards such as non-CME Prodigy cards, as well as general purpose PC/104 cards. See Section
2.5.1, “PC/104 Bus
Communications,” on page 46 for more information on communicating via the PC/104 bus.
Host access to the Prodigy/CME PC/104 card from the serial, CANbus, or Ethernet ports is provided by a protocol
called the
PMD Resource access Protocol (PRP). This easy-to-use yet powerful system utilizes actions, resources, and
addresses to access the Prodigy/CME PC/104 card’s functions. Various card functions are organized into resources,
and resources process actions sent to them. Actions can send information, request information, or command specific
events to occur. Addresses allow access to a specific resource on the card, or connected to the card, via the PC/104
bus, serial, CANbus, or Ethernet connections.
A basic communication to the Prodigy/CME PC/104 card consists of a 16-bit PRP header, and an optional message
body. The message body contains data associated with the specified PRP action, but some actions do not require a
message body. After a PRP communication is sent to the card, a return communication is sent by the Prodigy/CME
PC/104 card which consists of a PRP header and an optional return message body. The return message body may
contain information associated with the requested PRP action, or it may contain error information if there was a
problem processing the requested action.
There are five different resource types supported by the Prodigy/CME PC/104 card. The Device resource indicates
functionality that is addressed to the entire card, the MotionProcessor resource indicates a Magellan Motion Processor,
the CMotionEngine resource indicates the C-Motion Engine, the Memory resource indicates the dual-ported RAM
and the non-volatile RAM (Random Access Memory), and the Peripheral resource indicates a communications
connection.
There are ten different PRP actions including Command , which is used to send commands to resources such as the
Magellan Motion Processor, Send and Receive , which are used to communicate using the serial, CANbus, and Ethernet
ports, Read and Write , which are used to access memory-type devices such as the on-card dual-ported RAM, and the
non-volatile RAM, and Set and Get , which are used to load or read parameters.
Chapter 3, Accessing Card Resources , on page 57 describes all of these constructs in more detail. In the subsequent
sections of this chapter a summary of the PRP actions that are required to access each card function are included with
the descriptions of the card functions themselves.