Fujitsu F2MC-16LX Hardware Manual page 72

CHAPTER 3 INTERRUPT
I Configuration of hardware interrupt
The hardware-interrupt mechanism is divided into four parts, as shown in Table 3.4-1
"Hardware-interrupt mechanism". To use hardware interrupts, a program must contain settings
for the four locations.
Table 3.4-1 Hardware-interrupt mechanism
Peripheral function
Interrupt controller
CPU
"FFFC00 " to
H
"FFFFFF " in memory
H
I Suppressing hardware interrupt
Accepting a hardware interrupt request is suppressed under the following conditions:
❍ Suppressing hardware interrupts during writing to peripheral function control register
area
During writing to the peripheral function control register area, no hardware interrupt requests are
accepted. This prevents incorrect interrupt-related operations by the CPU during its rewriting of
the interrupt control registers with each peripheral function. Peripheral function control register
area refers not to a range of "000000
areas assigned to the control register within peripheral function control registers and data
register.
Figure 3.4-1 "Hardware interrupt requests during writing to peripheral function control register
area" shows hardware interrupt operations during writing to the peripheral function control
register area.
Figure 3.4-1 Hardware interrupt requests during writing to peripheral function control register area
Write instruction to peripheral function control register area
56
Hardware-interrupt mechanism
Interrupt enable bit, interrupt
request bit
Interrupt control register (ICR)
Interrupt enable flag (I)
Interrupt level mask register (ILM)
Micro-code
Interrupt vector table
MOV A,#08 MOV io,A
Interrupt request
is issued at this point
Control of interrupt request by peripheral
function
Setting for interrupt level and controlling
µDMA/Extended intelligent I/O service
2
(EI OS)
Identifying interrupt enable state
Comparing request interrupt level and
current interrupt level
Executing interrupt processing routine
Storing branch address for interrupt
processing
" to "0000FF " for the I/O addressing area, but to the
H H
MOV A,2000H
Not branched Branched
to interrupt to interrupt
Function
Interrupt processing