TC1796
System Units (Vol. 1 of 2)
Peripheral Control Processor (PCP)
User’s Manual 11-118 V2.0, 2007-07
PCP, V2.0
11.13 PCP Programming Notes and Tips
This section discusses constraints on the use of the PCP and points out some non-
obvious issues.
11.13.1 Notes on PCP Configuration
• Only one Context Model may be used at a time for all channels, and the PCP must
remain in that Context Model once started and configured.
• In order for a specific channel program to be enabled, its context must have
R7.CEN = 1. If R7.CEN = 0, then the channel program will terminate when invoked,
and cause a Disabled Channel Request error.
• The Channel Context Address from the FPI Bus as viewed during channel
configuration is as follows:
– Full Context Model: PRAM Base + 20
H
× n
– Small Context Model: PRAM Base + 10
H
× n
– Minimum Context Model: PRAM Base + 08
H
× n
where n is the channel number.
• PCP_CS.RCB and context must be consistent. If RCB is configured to 0, then each
channel program will start at the PC restored from its context. If the wrong address is
pre-configured in the context, the channel program will not operate properly.
• The programmer of the PCP may lock PCP_CS by setting PCP_CS.EIE = 1. When
the global ENDINIT bit is set, the PCP_CS register will no longer be writable, and
attempting to do so will cause an FPI Bus error.
• An error condition will result in an interrupt being sent to the local FPI Bus master.
The targeted interrupt service routine must be capable of dealing with the cause as
recorded in PCP_ES, and, if required, it must be able to return the halted channel
program to operation. The minimum required to do that is to set the context value of
R7.CEN = 1.
• The only PCP Register bit that can be dynamically modified during PCP operation is
the PCP_CS.EN bit. When writing to any other PCP Register bits, the user must
ensure that the PCP is disabled (PCP_CS.EN = 0) and that the PCP is quiescent
(PCP_CS.RS = 0).
To Next Page
Loading...
Need help?
General