Infineon Technologies TC1728 User Manual page 1004

The SRPN is used by service providers to select an Interrupt Service Routine (ISR)) or
Channel Program (in case of the PCP) to service the request. ISRs are associated with
Service Request Priority Numbers by an Interrupt Vector Table located in each service
provider. This means that the TC1728 Interrupt Vector Table is ordered by priority
number. This is unlike traditional interrupt architectures in which their interrupt vector
tables are ordered by the source of the interrupt. The TC1728 Interrupt Vector Table
allows a single peripheral to have multiple priorities for different purposes.
The range of values for SRPNs used in a system depends on the number of possible
active service requests and the user-definable organization of the Interrupt Vector Table.
The 8-bit SRPNs permit up to 255 sources to be active at one time (remembering that
the special SRPN value of 00
Note: Before modifying the content of an SRPN bit field, the corresponding SRN must
be disabled (SRE = 0).
SRPNs in the TC1728
In the TC1728, interrupt sources selecting the same Service Provider are also allowed
to have identical SRPN values. In this case, the software (interrupt service routine) must
check which of the interrupt sources with identical SRPN has become active.
Note that module-specific interrupt request flags must be available because the SRR
flags cannot be used for this check. SRR flags (meaning all SRR flags of interrupts with
identical SRPN values) are in general automatically reset by hardware when a service
request is acknowledged and serviced.
Note: This practice with identical SRPN values is not recommended as it is not portable
to other TriCore devices.
User's Manual
Interrupt, V1.4
excludes an SRN from taking part in arbitration).
H
13-7
TC1728
Interrupt System
V1.0, 2011-12