
System Integration Module
2-8
MC68328 DRAGONBALL PROCESSOR USER’S MANUAL
MOTOROLA
interrupt-acknowledge cycle. The interrupt controller generates a vector and presents it to
the core, which then jumps to the interrupt-service routine. If the core is in an interrupt-ser-
vice routine and a higher priority interrupt is posted, the process repeats and the higher pri-
ority is serviced. Interrupt priority is based on the interrupt level. Interrupts with the same
interrupt level are prioritized by the software during the execution of the interrupt-service
routine. The MC68328 processor provides one interrupt vector for each interrupt level. The
most significant 5 bits of the interrupt vector are user-programmable while the lower 3 bits
reflect the interrupt level being serviced.
All interrupts are maskable. Writing a 1 to a bit in the interrupt-mask register disables that
interrupt. If an interrupt is masked, its status is accessible in the interrupt-pending register.
2.3.2 Programmer’s Model
This section describes the bits and registers that control the interrupt module. All unused bits
may be written with no effect. When they are read, they indicate 0.
2.3.2.1 INTERRUPT VECTOR REGISTER (IVR).
This register programs the upper 5 bits of
the interrupt vector.During the interrupt-acknowledge cycle, the lower 3 bits encode the
interrupt level.
NOTE
If the interrupt-vector register is never programmed and an inter-
rupt occurs, the interrupt vector $0F is returned to indicate an
uninitialized interrupt.
2.3.2.2 VECTOR GENERATOR.
The interrupt controller block provides a vector to the
MC68EC000 core. Users have access to the upper 5 bits of the vector to place the vector
table anywhere in the vector space. Coding for the vectors is as follows:
7
6
5
4
3
2
1
0
VECTOR
0
0
0
Address: $(FF)FFF300
Reset Value: $00
Figure 2-5. Interrupt Control Register
Table 2-1. Interrupt Vectors
Interrupt
Vector
level 7
xxxxx111
level 6
xxxxx110
level 5
xxxxx101
level 4
xxxxx100
level 3
xxxxx011
level 2
xxxxx010
level 1
xxxxx001
Содержание DragonBall MC68328
Страница 5: ...vi MC68328 DRAGONBALL PROCESSOR USER S MANUAL MOTOROLA ...
Страница 25: ...Overview 1 14 MC68328 DRAGONBALL PROCESSOR USER S MANUAL MOTOROLA ...
Страница 45: ...System Integration Module 2 20 MC68328 DRAGONBALL PROCESSOR USER S MANUAL MOTOROLA ...
Страница 103: ...Parallel Ports 7 16 MC68328 DRAGONBALL PROCESSOR USER S MANUAL MOTOROLA ...
Страница 117: ...UART 8 14 MC68328 DRAGONBALL PROCESSOR USER S MANUAL MOTOROLA ...
Страница 127: ...SPI Master 10 6 MC68328 DRAGONBALL PROCESSOR USER S MANUAL MOTOROLA ...
Страница 137: ...Electrical Characteristics PRELIMINARY MOTOROLA MC68328 DRAGONBALL PROCESSOR USER S MANUAL 13 4 ...