NEC PD750008 User Manual

208

µPD750008 USER'S MANUAL

(6) Executing pending interrupt – interrupt occurs during interrupt processing (INTBT has higher

priority and INTT0 and INTCSI have lower priority) –

<1> When INTBT with the higher priority and INTT0 with the lower priority occur at the same time, the

processing of the interrupt with the higher priority is started (if there is no possibility that an interrupt

with the higher priority occurs while another interrupt with the higher priority is processed, DI IExx

is not necessary).

<2> When an interrupt with the lower priority occurs while the interrupt with the higher priority is executed,

the interrupt with the lower priority is kept pending.

<3> When the interrupt with the higher priority has been processed, INTCSI with the higher priority of

the pending interrupts is executed.

<4> When the processing of INTCSI has been completed, the pending INTT0 is processed.

Reset

EI
EI
EI
MOV
MOV

IEBT
IET0
IECSI
A, #9
IPS, A

INTT0

RETI

<INTT0

service program

INTBT

<INTBT

service program

<4> RETI

<INTCSI

service program

<3> RETI

POP rp

PUSH rp

<2> INTCSI

<1>