C505_9708 SIEMENS [Siemens Semiconductor Group], C505_9708 Datasheet - Page 184

• Manufacturer Part Number: C505_9708
• Description: 8-Bit CMOS Microcontroller
• Manufacturer: SIEMENS [Siemens Semiconductor Group]

7.2
The following table shows the interrupt grouping of the C505 interrupt sources.
Table 7-1
Interrupt Source Structure
Interrupt
Group
1
2
3
4
5
6
Each pair of interrupt sources can be programmed individually to one of four priority levels by setting
or clearing one bit in the special function register IP0 and one in IP1. A low-priority interrupt can be
interrupted by a high-priority interrupt, but not by another interrupt of the same or a lower priority. An
interrupt of the highest priority level cannot be interrupted by another interrupt source.
lf two or more requests of different priority levels are received simultaneously, the request of the
highest priority is serviced first. lf requests of the same priority level are received simultaneously, an
internal polling sequence determines which request is to be serviced first. Thus, within each priority
level there is a second priority structure determined by the polling sequence, as follows.
Semiconductor Group
– Within one interrupt group the “left“ interrupt is serviced first
– The interrupt groups are serviced from top to bottom of the table.
Interrupt Priority Level Structure
Associated Interrupts
High priority
External interrupt 0
Timer 0 overflow
External interrupt 1
Timer 1 overflow
Serial channel interrupt
Timer 2 interrupt
A/D converter interrupt
CAN controller interrupt (C505C) /
Software Interrupt (IRCON.1)
External interrupt 3
External interrupt 4
External interrupt 5
External interrupt 6
7-13
Low priority
Interrupt System
Priority
High
Low
C505 / C505C
1997-08-01