Exception Control
MC68HC908QL4 MC68HC908QL3 MC68HC908QL2 Data Sheet, Rev. 4
Freescale Semiconductor
127
13.6.2 Interrupt Status Registers
The flags in the interrupt status registers identify maskable interrupt sources.
Table 13-3
summarizes the
interrupt sources and the interrupt status register flags that they set. The interrupt status registers can be
useful for debugging.
IF1 and IF3–IF6 — Interrupt Flags
These flags indicate the presence of interrupt requests from the sources shown in
Table 13-3
.
1 = Interrupt request present
0 = No interrupt request present
Bit 0, 1, and 3— Always read 0
13.6.2.1 Interrupt Status Register 2
IF7–I
F
14 — Interrupt Flags
This flag indicates the presence of interrupt requests from the sources shown in
Table 13-3
.
1 = Interrupt request present
0 = No interrupt request present
Table 13-3. Interrupt Sources
Priority
Source
Flag
Mask
(1)
1. The I bit in the condition code register is a global mask for all interrupt sources except the SWI instruction.
INT
Register Flag
Vector
Address
Highest
Lowest
Reset
—
—
—
$FFFE–$FFFF
SWI instruction
—
—
—
$FFFC–$FFFD
IRQ pin
IRQF1
IMASK1
IF1
$FFFA–$FFFB
Timer channel 0 interrupt
CH0F
CH0IE
IF3
$FFF6–$FFF7
Timer channel 1 interrupt
CH1F
CH1IE
IF4
$FFF4–$FFF5
Timer overflow interrupt
TOF
TOIE
IF5
$FFF2–$FFF3
SLIC interrupt
SLCF
SLCIE
IF9
$FFEA–$FFEB
Keyboard interrupt
KEYF
IMASKK
IF14
$FFE0–$FFE1
ADC conversion complete interrupt
COCO
AIEN
IF15
$FFDE–$FFDF
Bit 7
6
5
4
3
2
1
Bit 0
Read:
IF6
IF5
IF4
IF3
0
IF1
0
0
Write:
R
R
R
R
R
R
R
R
Reset:
0
0
0
0
0
0
0
0
R
= Reserved
Figure 13-11. Interrupt Status Register 1 (INT1)
Bit 7
IF14
R
0
R
6
5
4
3
2
1
Bit 0
IF7
R
0
Read:
Write:
Reset:
IF13
R
0
IF12
R
0
IF11
R
0
IF10
R
0
IF9
R
0
IF8
R
0
= Reserved
Figure 13-12. Interrupt Status Register 2 (INT2)