User’s Manual
C166S V1 SubSystem
System Overview
User’s Manual
2-6
V 1.6, 2001-08
2.1.5
Programmable Multiple Priority Interrupt and PEC System
The following enhancements have been included to allow processing of a large number
of interrupt sources:
1. Peripheral Event Controller (PEC): This processor is used to off-load many interrupt
requests from the CPU. It avoids the overhead of entering and exiting interrupt or trap
routines by performing single-cycle interrupt-driven byte or word data transfers
between any two locations with an optional increment of either the PEC source or the
destination pointer. Just one cycle is ’stolen’ from the current CPU activity to perform
a PEC service.
2. Multiple Priority Interrupt Controller (ITC): This controller allows all interrupts to be
placed at any specified priority. Interrupts may also be grouped, which provides the
user with the ability to prevent similar priority tasks from interrupting each other. For
each of the possible interrupt sources there is a separate control register, which
contains an interrupt request flag, an interrupt enable flag and an interrupt priority
bitfield. Once having been accepted by the CPU, an interrupt service can only be
interrupted by a higher prioritized service request. For standard interrupt processing,
each of the possible interrupt sources has a dedicated vector location.
3. Multiple Register Banks: This feature allows the user to specify up to sixteen general
purpose registers located anywhere in the internal DPRAM (Dual Port RAM). A single
one-machine-cycle instruction allows to switch register banks from one task to
another.
4. Interruptible Multiple Cycle Instructions: Reduced interrupt latency is provided by
allowing multiple-cycle instructions (multiply, divide) to be interruptible.
5. Hardware Traps: The C166S also provides an excellent mechanism to identify and to
process exceptions or error conditions that arise during run-time, so called ’Hardware
Traps’. Hardware traps cause an immediate non-maskable system reaction which is
similar to a standard interrupt service (branching to a dedicated vector table location).
The occurrence of a hardware trap is additionally signified by an individual bit in the
Trap Flag Register (TFR). Except for another higher prioritized trap service being in
progress, a hardware trap will interrupt any current program execution. In turn,
hardware trap services can normally not be interrupted by standard or PEC interrupts.
6. Software Traps: Software interrupts are supported by means of the ’TRAP’ instruction
in combination with an individual trap (interrupt) number.
Содержание C166S V1 SubSystem
Страница 10: ...User s Manual C166S V1 SubSystem User s Manual I 6 V 1 6 2001 08...
Страница 16: ...User s Manual C166S V1 SubSystem Introduction User s Manual 1 6 V 1 6 2001 08...
Страница 126: ...User s Manual C166S V1 SubSystem Central Processing Unit User s Manual 3 96 V 1 6 2001 08...
Страница 178: ...User s Manual C166S V1 SubSystem Memory Organization User s Manual 4 52 V 1 6 2001 08...
Страница 206: ...User s Manual C166S V1 SubSystem Instruction Set User s Manual 5 28 V 1 6 2001 08...
Страница 306: ...User s Manual C166S V1 SubSystem Detailed Instruction Set User s Manual 6 100 V 1 6 2001 08...
Страница 362: ...User s Manual C166S V1 SubSystem The External Bus Interface User s Manual 8 40 V 1 6 2001 08...
Страница 452: ...User s Manual C166S V1 SubSystem General Purpose Timer Unit User s Manual 12 44 V 1 6 2001 08...
Страница 454: ...User s Manual C166S V1 SubSystem Instruction Index User s Manual 13 2 V 1 6 2001 08...
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