S3C8248/C8245/P8245/C8247/C8249/P8249
INTERRUPT STRUCTURE
5-11
INTERRUPT PRIORITY REGISTER (IPR)
The interrupt priority register, IPR (set 1, bank 0, FFH), is used to set the relative priorities of the interrupt levels
in the microcontroller’s interrupt structure. After a reset, all IPR bit values are undetermined and must therefore
be written to their required settings by the initialization routine.
When more than one interrupt sources are active, the source with the highest priority level is serviced first. If two
sources belong to the same interrupt level, the source with the lower vector address usually has the priority (This
priority is fixed in hardware).
To support programming of the relative interrupt level priorities, they are organized into groups and subgroups by
the interrupt logic. Please note that these groups (and subgroups) are used only by IPR logic for the IPR register
priority definitions (see Figure 5-7):
Group A
IRQ0, IRQ1
Group B
IRQ2, IRQ3, IRQ3
Group C
IRQ5, IRQ6, IRQ7
IPR
Group B
IPR
Group C
IRQ2
B1
IRQ4
B2
IRQ3
B22
B21
IRQ5
C1
IRQ7
C2
IRQ6
C22
C21
IPR
Group A
IRQ1
A2
IRQ0
A1
Figure 5-7. Interrupt Request Priority Groups
As you can see in Figure 5-8, IPR.7, IPR.4, and IPR.1 control the relative priority of interrupt groups A, B, and C.
For example, the setting "001B" for these bits would select the group relationship B > C > A. The setting "101B"
would select the relationship C > B > A.
The functions of the other IPR bit settings are as follows:
— IPR.5 controls the relative priorities of group C interrupts.
— Interrupt group C includes a subgroup that has an additional priority relationship among the interrupt levels 5,
6, and 7. IPR.6 defines the subgroup C relationship. IPR.5 controls the interrupt group C.
— IPR.0 controls the relative priority setting of IRQ0 and IRQ1 interrupts.
Summary of Contents for S3C8248
Page 31: ...ADDRESS SPACES S3C8248 C8245 P8245 C8247 C8249 P8249 2 20 NOTES ...
Page 107: ...INTERRUPT STRUCTURE S3C8248 C8245 P8245 C8247 C8249 P8249 5 18 NOTES ...
Page 195: ...INSTRUCTION SET S3C8248 C8245 P8245 C8247 C8249 P8249 6 88 NOTES ...
Page 221: ...I O PORTS S3C8248 C8245 P8245 C8247 C8249 P8249 9 16 NOTES ...
Page 245: ...16 BIT TIMER 0 1 S3C8248 C8245 P8245 C8247 C8249 P8249 12 10 NOTES ...
Page 249: ...WATCH TIMER S3C8248 C8245 P8245 C8247 C8249 P8249 13 4 NOTES ...
Page 267: ...A D CONVERTER S3C8248 C8245 P8245 C8247 C8249 P8249 15 6 NOTES ...
Page 299: ...S3P8245 P8249 OTP S3C8248 C8245 P8245 C8247 C8249 P8249 21 8 NOTES ...
Page 307: ......
Page 309: ......
Page 311: ......
Page 313: ......