Operations Of Dtp/External Interrupt Unit - Fujitsu F2MC-16LX Hardware Manual

18.3 Operations of DTP/External Interrupt Unit

This section describes the operations of the DTP/external interrupt unit.
I Operation of external interrupt unit
If, after an external interrupt request has been set, the interrupt source specified in the ELVR
register is input to the corresponding pin, the external interrupt unit will generate an interrupt
request signal for the interrupt controller. Interrupts that are generated by the interrupt controller
at the same time will be distinguished by priority. The interrupt controller will generate an
interrupt request to the F
the highest priority. The F
the processor status (PS) with the interrupt request level. If the request level is found to be
higher than the value expressed by the ILM bits, the hardware interrupt handling microprogram
starts immediately after the currently executed instruction is completed.
Figure 18.3-1 "External interrupt operation" shows the operational flow for external interrupts.
External interrupt/DTP unit
ELVR
EIRR
ENIR
Interrupt
source
The interrupt handling microprogram reads data from the interrupt vector area and generates an
interrupt acknowledge signal for the interrupt controller. After that, it transfers the jump
destination address of the macro instruction, which is obtained from the interrupt vector, to the
program counter, and execution continues with the user's interrupt handling program.
2
MC-16LX CPU if the interrupt from the corresponding resource has
2
MC-16LX CPU compares the interrupt level mask register (ILM) in
Figure 18.3-1 External interrupt operation
Interrupt controller
Other
request
ICR
yy
ICF
xx
CHAPTER 18 DTP/EXTERNAL INTERRUPT UNIT
IL
CMP
ILM
INTA
2
F MC-16LXCPU
CMP
351