SAB-C165 SIEMENS [Siemens Semiconductor Group], SAB-C165 Datasheet - Page 14

• Manufacturer Part Number: SAB-C165
• Description: C16x-Family of High-Performance CMOS 16-Bit Microcontrollers
• Manufacturer: SIEMENS [Siemens Semiconductor Group]

Interrupt System
With an interrupt response time within a range from just 250 ns to 600 ns (in case of internal
program execution), the C165 is capable of reacting very fast to the occurrence of non-deterministic
events.
The architecture of the C165 supports several mechanisms for fast and flexible response to service
requests that can be generated from various sources internal or external to the microcontroller. Any
of these interrupt requests can be programmed to being serviced by the Interrupt Controller or by
the Peripheral Event Controller (PEC).
In contrast to a standard interrupt service where the current program execution is suspended and
a branch to the interrupt vector table is performed, just one cycle is ‘stolen’ from the current CPU
activity to perform a PEC service. A PEC service implies a single byte or word data transfer between
any two memory locations with an additional increment of either the PEC source or the destination
pointer. An individual PEC transfer counter is implicity decremented for each PEC service except
when performing in the continuous transfer mode. When this counter reaches zero, a standard
interrupt is performed to the corresponding source related vector location. PEC services are very
well suited, for example, for supporting the transmission or reception of blocks of data. The C165
has 8 PEC channels each of which offers such fast interrupt-driven data transfer capabilities.
A separate control register which contains an interrupt request flag, an interrupt enable flag and an
interrupt priority bitfield exists for each of the possible interrupt sources. Via its related register, each
source can be programmed to one of sixteen interrupt priority levels. Once having been accepted
by the CPU, an interrupt service can only be interrupted by a higher prioritized service request. For
the standard interrupt processing, each of the possible interrupt sources has a dedicated vector
location.
Fast external interrupt inputs are provided to service external interrupts with high precision
requirements. These fast interrupt inputs feature programmable edge detection (rising edge, falling
edge or both edges).
Software interrupts are supported by means of the ‘TRAP’ instruction in combination with an
individual trap (interrupt) number.
The following table shows all of the possible C165 interrupt sources and the corresponding
hardware-related interrupt flags, vectors, vector locations and trap (interrupt) numbers:
Note: Four nodes in the table (X-Peripheral nodes) are prepared to accept interrupt requests from
Semiconductor Group
integrated X-Bus peripherals. Nodes, where no X-Peripherals are connected, may be used
to generate software controlled interrupt requests by setting the respective XPnIR bit. Also
the three listed Software Nodes can be used for this purpose.
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C165