Chapter 3. Accessing Card Resources; Resource Addressing - Performance Motion Devices Prodigy Series User Manual

3.Accessing Card Resources
In This Chapter


Resource Addressing


Accessing the Communications Ports

Accessing On-Card Resources

Accessing Magellan-Attached Devices

PRP Communication Formats
3.1 Resource Addressing
The Prodigy/CME PC/104 card's various features and capabilities are organized into groups called 'resources.' For
example, to communicate with the Prodigy/CME PC/104 card's Magellan Motion Processor, the host controller sends
a command to the MotionProcessor
To address different types of resources, the Prodigy/CME PC/104 cards provides a general purpose resource addressing
scheme called the PMD Resource access Protocol (PRP). PRP is a sophisticated general purpose addressing scheme that
allows:
• one or more host controllers to communicate with Prodigy/CME PC/104 cards
• Prodigy/CME cards to communicate with each other
• Prodigy/CME cards to communicate with other PMD products such as IONs and
non-/CME Prodigy cards
• Prodigy/CME cards to communicate with user-designed hardware, or other off-the-shelf hardware.
3.1.1 PMD Resource Access Protocol (PRP)
The core of the PMD Resource access Protocol is a header that accompanies all PRP communications. Figure 3-1 on
page 58 shows the format of the resource access protocol header. The PRP header is a single 16-bit word divided into
five fields. Normally, the PRP header is immediately followed by a message body, but there are certain communications
that do not require a message body. PRP headers are used in both the outgoing, and the response packet. The returned
PRP header is 1 byte in length, consisting of the version field, the status code field, and 4 reserved bits.
Prodigy/CME PC/104 User's Guide
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