Performance Motion Devices PR8358120, User Manual

Page: 65 / 103

Accessing Card Resources
Prodigy/CME PC/104 User’s Guide
65
3
Figure 3-5:
Host Controller
& Magellan-
attached
Devices
In this ‘bridge’ configuration, the host controller (or the Prodigy/CME PC/104 card’s C-Motion Engine) can access
the PC/104-connected Prodigy card very similarly to the way in which the on-card Magellan is addressed. To
accomplish this however, a different method is used to create access to the Magellan compared to the method
described for on-card Magellan access in (see Section
3.3, “Accessing On-Card Resources,” on page 63 for details).
Rather than sending PRP messages to the on-card MotionProcessor resource, first a raw peripheral connection is
opened, and then the Open action with a sub-action of MotionProcessor is used to open a new MotionProcessor
resource. The following PRP code sequence illustrates:
Note that as the command sequence above shows, after the new MotionProcessor resource addresses are created using
the Open action, subsequent Magellan commands to the slave Prodigy-PC/104 are identical in format to commands
to the on-card Magellan. This illustrates a very powerful feature of the PRP system which is that it allows resources to
be addressed transparently by the host controller (or C-Motion Engine module), making it easy to create and access
networks of PMD products.
Note also that the Open action can be used with different resource types. In Section 3.2.1, “Peripheral Connections,”
on page 60 it was used with a resource type of Device to open a peripheral connection. In the above example it was
used with a resource type of Peripheral to open a connection to a Magellan Motion Processor.
NewPeriphID = PRP Device, Addr 0, Open // Open an ISA peripheral connection to connect to the slave
// Prodigy-PC/104 card
NewMtnProcID = PRP Peripheral, Addr NewPeriphID, Open
// Use the opened peripheral connection to create a new
// MotionProcessor resource using the Open
action with
// sub-action specifying MotionProcessor. A new MotionProcessor
// resource address is loaded into the message body
PRP MotionProcessor, Addr NewMtnProcID, Command
// Send Magellan command packet to the slave Prodigy-PC/104’s
// Magellan Motion
// Processor using the standard method of communicating with
// MotionProcessor resources
Ethernet/TCP
C-Motion
Engine
Magellan
Prodigy/CME
PC/104 Card
Host Controller
PC/104 Bus
Prodigy
Card