External Interrupt Circuit Interrupts - Fujitsu F2MC-8L MB89620 Series Hardware Manual

4
12.

External Interrupt Circuit Interrupts

The external interrupt circuit can generate interrupt requests when it detects a
specified edge on the signal input to an external interrupt pin.
n Interrupts for External Interrupt Circuit Operation
When a specified edge on an external interrupt input is detected, corresponding external
interrupt request flag bit (EIC1, EIC2: EIR0 to EIR3) is set to "1". At this time, an interrupt
requests (IRQ0 to IRQ3) to the CPU are generated if the corresponding interrupt request enable
bit is enabled (EIC1, EIC2: EIE0 to EIE3 = "1"). Write "0" to the corresponding external interrupt
request flag bit in the interrupt processing routine to clear the interrupt request.
Check: When enabling interrupts (EIE0 to EIE3 = "1") after wake-up from a reset, always clear the
Notes: • Wake-up from stop mode by an interrupt is possible using only the external interrupt circuit.
n Register and Vector Table for External Interrupt Circuit Interrupts
Table 12.4 Register and Vector Table for External Interrupt Circuit Interrupts
Interrupt
IRQ0
IRQ1
IRQ2
IRQ3
Reference: See Section 3.4.2, "Interrupt Processing" for details on the interrupts operation.
240
CHAPTER 12 EXTERNAL INTERRUPT CIRCUIT (EDGE)
corresponding external interrupt request flag bit (EIR0 to EIR3 = "0") at the same time.
Interrupt processing cannot return if the external interrupt request flag bit is "1" and the interrupt
request enable bit is enabled. In the interrupt processing routine, always clear the external
interrupt request flag bit.
• An interrupt request is generated immediately if the external interrupt request flag bit is "1" when
the interrupt request enable bit is changed from disabled to enabled ("0" → "1").
Interrupt level setting register
Register
ILR1 (007C )
H
Setting bits
L01 (Bit 1) L00 (Bit 0)
L11 (Bit 3) L10 (Bit 2)
L21 (Bit 5) L20 (Bit 4)
L31 (Bit 7) L30 (Bit 6)
Vector table address
Upper Lower
FFFA FFFB
H H
FFF8 FFF9
H H
FFF6 FFF7
H H
FFF4 FFF5
H H
MB89620 series