
OctalLIU
TM
PEF 22508 E
Functional Description
Data Sheet
50
Rev. 1.0, 2005-06-02
Figure 14
Interrupt Status Registers
Each interrupt indication bit of the registers ISR can be selectively masked by setting the corresponding bit in the
corresponding mask registers IMR. If the interrupt status bits are masked they neither generate an interrupt at INT
nor are they visible in ISR. All reserved bits in the mask registers IMR must not be written with the value 0.
GIS, the non-maskable “Global” Interrupt Status Register per channel, serves as pointer to pending interrupts
sourced by registers ISR(1:4), ISR6 and ISR7.
The non-maskable Channel Interrupt Status Register CIS serves as channel pointer to pending interrupts sourced
by registers GIS.
After the OctalLIU
TM has requested an interrupt by activating its INT pin, the external micro controller should first
read the register CIS to identify the requesting interrupt source channel. Then it should read the Global Interrupt
Status register GIS to identify the requesting interrupt source register ISR of that channel.
After reading the assigned interrupt status registers ISR(1:4), ISR6 and ISR7, the pointer bit in register GIS is
cleared or updated if another interrupt requires service. After all bits ISR(7:0) of a register GIS are cleared, the
assigned bit in register CIS is cleared. After all bits in register CIS are cleared the INT pin will be deactivated.
If all pending interrupts are acknowledged by reading (GIS is reset), pin INT goes inactive.
Updating of interrupt status registers ISR(1:4), ISR6 and ISR7 and GIS is only prohibited during read access.
Global“
Interrupt Status
Register GIS
(per channel)
IMR1
ISR1
IMR3
ISR3
IMR4
ISR4
OctalLIU_ISR_2
IMR6
ISR6
IMR7
ISR7
GIS4
GIS1
GIS2
GIS3
Status Registers and Masking
(shownfor onechannel)
Channel
Interrupt Status
Register CIS ,
global
channel
...
different Status bits
...
INT
channel
GIS8
GIS7
GIS6
GIS5
... 1to8
...
1to8
PLL
PLLLC
PLLL
GIS2
GIMR
PLLLS not visible
VIS
GCR
VISPLL IPC
ISR1
ISR3
ISR4
ISR6
ISR7
ISR1
ISR3
ISR4
ISR6
ISR7
IMR2
ISR2
...
ISR2
R2