PKP
VS1000 P
ROGRAMMER
’
S
G
UIDE
VSMPG
•
Enable registers, which contain enable/disable bits for each interrupt source. Bit
pairs configure the interrupt priority and disable.
•
Origin registers, which contain the source flags for each interrupt. A request from
an interrupt source sets the corresponding bit. A bit is automatically reset when a
request for the source is generated.
•
Enable counter register, which contains the value of the General Interrupt Enable
counter, and two registers for increasing and decreasing the value.
15.1.1
Enable INT_ENABLE[L/H][0/1]
Interrupt enable registers selectively masks interrupt sources. Enable registers 0 contain
sources 0..15 and enable registers 1 contain sources 16..31. Each source has two
enable bits: one in the enable low and one in the enable high register. If both bits are
zero, the corresponding interrupt source is not enabled, otherwise the bits select the
interrupt priority.
High
Low
Priority
0
0
Source disabled
0
1
Priority 1
1
0
Priority 2
1
1
Priority 3
Priorities only matter when the interrupt controller decides which interrupt to generate
for the core next. This happens whenever two interrupt sources request interrupts at the
same time, or when interrupts become enabled after an interrupt handler routine or part
of code where the interrupts have been disabled.
15.1.2
Origin INT_ORIGIN[0/1]
If an interrupt source requests an interrupt, the corresponding bit in the interrupt ori-
gin register (ORIGIN0 or ORIGIN1) will be set to ’1’. If an interrupt source is enabled
(using ENABLE registers), the interrupt controller generates an interrupt request signal
for VSDSP with the corresponding vector value. The bit in the origin registers is reset
automatically after the interrupt is requested.
If the source is not enabled, the processor can read the origin register state and perform
any necessary actions without using interrupt generation, i.e. polling of the interrupt
sources is also possible. The bits in the interrupt origin registers can be cleared by
writing ’1’ to them.
A read from the interrupt origin register returns the register state.
A write to the interrupt origin register clears bits in the interrupt origin register. All ’1’-
bits in the written value cause the corresponding bits in the interrupt origin register to
be cleared. All zero-bits cause the corresponding bits in the interrupt origin register to
Rev. 0.20
2011-10-04
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