
Data Sheet
ADuC7023
| Page 77 of 96
IRQEN Register
Name:
IRQEN
Address:
0xFFFF0008
Default value:
0x00000000
Access:
Read/write
Function:
IRQEN provides the value of the current
enable mask. When each bit is set to 1, the
source request is enabled to create an IRQ
exception. When each bit is set to 0, the
source request is disabled or masked, which
does not create an IRQ exception.
To clear an already enabled interrupt source,
users must set the appropriate bit in the
IRQCLR register. Clearing an interrupt
IRQEN bit does not disable this interrupt.
IRQCLR Register
Name:
IRQCLR
Address:
0xFFFF000C
Default value:
0x00000000
Access:
Write
Function:
IRQCLR (write-only register) clears the
IRQEN register to mask an interrupt source.
Each bit set to 1 clears the corresponding bit
in the IRQEN register without affecting the
remaining bits. The pair of registers, IRQEN
and IRQCLR, independently manipulate the
enable mask without requiring an atomic
read-modify-write.
FAST INTERRUPT REQUEST (FIQ)
The fast interrupt request (FIQ) is the exception signal to enter
the FIQ mode of the processor. It is provided to service data
transfer or communication channel tasks with low latency. The
FIQ interface is identical to the IRQ interface and provides the
second level interrupt (highest priority). Four 32-bit registers
are dedicated to FIQ: FIQSIG, FIQEN, FIQCLR, and FIQSTA.
Bit 31 to Bit 1 of FIQSTA are logically OR’ed to create the FIQ
signal to the core and to Bit 0 of both the FIQ and IRQ registers
(FIQ source).
The logic for FIQEN and FIQCLR does not allow an interrupt
source to be enabled in both IRQ and FIQ masks. A bit set to 1
in FIQEN clears, as a side effect, the same bit in IRQEN. Likewise,
a bit set to 1 in IRQEN clears, as a side effect, the same bit in
FIQEN. An interrupt source can be disabled in both IRQEN
and FIQEN masks.
FIQSIG
FIQSIG reflects the status of the different FIQ sources. If a
peripheral generates an FIQ signal the corresponding bit in
the FIQSIG is set, otherwise it is cleared. The FIQSIG bits are
cleared when the interrupt in the particular peripheral is cleared.
All FIQ sources can be masked in the FIQEN MMR. FIQSIG is
read only.
FIQSIG Register
Name:
FIQSIG
Address:
0xFFFF0104
Default value: 0x00000000
Access:
Read only
FIQEN
FIQEN provides the value of the current enable mask. When a bit is
set to 1, the corresponding source request is enabled to create an
FIQ exception. When a bit is set to 0, the corresponding source
request is disabled or masked which does not create an FIQ
exception. The FIQEN register cannot be used to disable an
interrupt.
FIQEN Register
Name:
FIQEN
Address:
0xFFFF0108
Default value: 0x00000000
Access:
Read/write
FIQCLR
FIQCLR is a write-only register that allows the FIQEN register
to clear in order to mask an interrupt source. Each bit that is set
to 1 clears the corresponding bit in the FIQEN register without
affecting the remaining bits. The pair of registers, FIQEN and
FIQCLR, allows independent manipulation of the enable mask
without requiring an atomic read-modify-write.
This register should only be used to disable an interrupt source
when in the interrupt sources interrupt service routine or if the
peripheral is temporarily disabled by its own control register.
This register should not be used to disable an IRQ source if that
IRQ source has an interrupt pending or could have an interrupt
pending.
FIQCLR Register
Name:
FIQCLR
Address:
0xFFFF010C
Default value:
0x00000000
Access:
Write only
Rev. E