MC68HC705C Motorola, MC68HC705C Datasheet - Page 55

• Manufacturer Part Number: MC68HC705C
• Description: HCMOS Microcontroller Unit
• Manufacturer: Motorola

4.4 Interrupt Processing
MC68HC705C8A — Rev. 2.0
MOTOROLA
The CPU takes these actions to begin servicing an interrupt:
The return-from-interrupt (RTI) instruction causes the CPU to recover
the CPU registers from the stack as shown in
Function
interrupts
interrupts
interrupts
Software
interrupt
External
interrupt
1. Stores the CPU registers on the stack in the order shown in
2. Sets the I bit in the CCR to prevent further interrupts
3. Loads the program counter with the contents of the appropriate
Reset
(SWI)
Timer
SCI
SPI
Figure 4-4
interrupt vector locations as shown in
RESET pin
Port B pins
Table 4-1. Reset/Interrupt Vector Addresses
User code
MODF bit
Power-on
TDRE bit
RDRF bit
IDLE bit
SPIF bit
Source
IRQ pin
OCF bit
TOF bit
ICF bit
OR bit
TC bit
logic
Interrupts
OCIE bit
TOIE bit
TCIE bit
ICIE bit
ILIE bit
RIE bit
Local
Mask
None
None
None
SPIE
Global
Mask
None
None
I bit
I bit
I bit
I bit
(1 = Highest)
Same priority
instruction
Table
Priority
as any
Figure
1
2
3
4
5
4-1.
4-4.
Interrupt Processing
Vector Address
$1FFC–$1FFD
$1FFE–$1FFF
$1FFA–$1FFB
$1FF8–$1FF9
$1FF6–$1FF7
$1FF4–$1FF5
Technical Data
Interrupts
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