Abov MC96FR364B, User Manual

Page: 51 / 194

November, 2018 Rev.1.4 51
10. Interrupt Controller
10.1 Overview
The interrupt controller has the following features to handle interrupt request from internal peripherals
or external pins.
- support up to 21 interrupt sources NOTE
- 6 group of 4 priority level
- multiple interrupts handling
- global enable by EA bit and selective control by IEx bit
- Interrupt latency : 3~9 machine cycles in single interrupt system
NOTE
Interrupt controller can accept up to 24 interrupt sources, but there are only 19 interrupt sources in
MC96FR364B.
Interrupt controller has 4 Interrupt Enable Registers (IE, IE1, IE2, IE3) and 2 Interrupt Priority
Registers (IP, IP1). There are 16 interrupt sources in MC96FR364B and overall control is done by EA
bit in IE register. When EA is set to 0, all interrupt requests are ignored. When EA is set to 1, each
interrupt request is accepted or not by INTnE bit in IEx registers. 16 interrupt sources are assigned to
6 groups and each group can have different priority according to IP and IP1 registers.
By default all interrupt sources are level-triggered, but external interrupts can be set to operate in
edge-trigger mode. If more than 2 interrupts of different group priority are requested almost at the
same time, the request of higher priority is serviced first. And among the requests of same priority, an
internal polling sequence determines which request is serviced, ie, the interrupt having lower priority
number in Table 10-2 is serviced first. Even in interrupt service routine, another interrupt of higher
priority can interrupt the execution of service routine for the lower priority by software configuration.
Interrupt
Group Highest Lowest
0 (Bit0)
Interrupt0 Interrupt6 Interrupt12 Interrupt18
Highest
1 (Bit1)
Interrupt1 Interrupt7 Interrupt13 Interrupt19
2 (Bit2)
Interrupt2 Interrupt8 Interrupt14 Interrupt20
3 (Bit3)
Interrupt3 Interrupt9 Interrupt15 Interrupt21
4 (Bit4) Interrupt4 Interrupt10 Interrupt16 Interrupt22
5 (Bit5)
Interrupt5 Interrupt11 Interrupt17 Interrupt23
Lowest
Table 10-1 Interrupt Group and Default Priority