Infineon Technologies TC1784, Руководство пользователя

Страница: 701 / 2350

TC1784
Peripheral Control Processor (PCP)
User´s Manual 10-36 V1.1, 2011-05
PCP, V2.09
they are fully controlled by the PCP kernel; they are read-only registers during PCP
operation. The user cannot generate interrupts by writing to them.
The twelve service request nodes are split into four groups.
•
The first group, containing registers PCP_SRC0 and PCP_SRC1, handles implicit
PCP service requests targeted to the CPU. The Type-of-Service control fields, TOS,
of these registers are hard-wired to 00
B
, directing the requests to the CPU.
• The second group, registers PCP_SRC2 and PCP_SRC3, handles the service
requests targeted to the PCP itself. The respective TOS field of these registers are
hard-wired to 01
B
, directing the requests to the PCP.
• The third group, containing registers PCP_SRC4 to PCP_SRC8, have
programmable TOS fields which allow these registers to be assigned (at
configuration time) to any of the available interrupt buses.
• The fourth group, containing registers PCP_SRC9, PCP_SRC10 and PCP_SRC11,
are an extended version of a standard Service Request Node. These handle service
requests targeted to the PCP itself, including service requests representing a
suspended interrupt. The respective TOS field of these registers are hard-wired to
01
B
, directing the requests to the PCP.
The service request enable bits, SRE, of the PCP_SRCx registers are hard-wired to 1,
meaning these service requests are always enabled.
Note: The number of interrupt buses is device-dependent. Programming a PCP_SRCx
register (x = 4 to 8) with a TOS value representing a non-available interrupt bus
(10
B
or 11
B
in the TC1784) will disable Service Request Node x.
The actual service request flag and the service request priority number of the
PCP_SRCx registers are updated by the PCP when it generates an implicit service
request. The way this is performed is described in the following section.
The service request nodes in each of the groups described above are implemented as
queues with the appropriate number of entries. When the PCP generates an implicit
service request, it places the request into the next available free entry of the appropriate
queue rather than writing it into a specific register. Queue management logic
automatically ensures proper handling of the queue. If all entries of a queue are filled with
pending service requests, the queue management reports this condition to the PCP
kernel via a “queue full” signal.
In the following descriptions, the terms “CPU Queue” and “PCP Queue” are used to refer
to the queues in the two groups of PCP service request nodes.
10.6.4 Issuing PCP Service Requests
The PCP can issue implicit service requests on the execution of an EXIT instruction,
when suspending a channel, or when an error occurs during a channel program
execution. While the service request generation for the EXIT instruction is optional, a
service request is always generated when a channel is suspended or an error occurs.