Figure 3.4-2 Interrupt Processing - Fujitsu F2MC-8L Series Hardware Manual

START
(1)
Initialize peripheral
YES
Is an interrupt
request present at the
peripheral?
NO
request output enabled
for the peripheral?
Main program
(2)
execution
(7)
Restore PC and PS
(1) After a reset, all interrupt requests are disabled.
Initialize the peripheral functions that are to generate interrupts in the peripheral
function initialization program, set the interrupt levels in the appropriate interrupt level
setting registers (ILR1, ILR2, ILR3), and start peripheral function.
The interrupt level can be set to 1, 2 or 3. Level 1 is the highest priority, followed by
level 2. Setting level 3 disables the interrupt for that peripheral function.
(2) Execute the main program (for multiple interrupts, execute the interrupt processing
routine).

Figure 3.4-2 Interrupt Processing

Register
IPLA
(7)
(6)
Enable FF
Request FF
Is interrupt
(3)
YES
NO
Check the interrupt priority level
(4)
and transfer the level to the CPU
Compare the level with
the IL bits in PS
Is the level
higher than IL?
NO
Interrupt processing routine
Clear interrupt request
Execute interrupt processing
RETI
Condition code
register (CCR)
PS I
file
IR
Check
(5)
F 2 MC-8L·CPU
RAM
·
·
·
AND
(3)
Peripherals
YES
I-flag = 1?
NO
Save PC and PS to the stack
(6)
PC ¬ interrupt vector
Update IL in PS
3.4 Interrupts
IL
Comparator
Wake-up from stop mode
Wake-up from sleep mode
Wake-up from watch mode
(4)
Interrupt
controller
(5)
YES
45