TMP47C990E TOSHIBA [Toshiba Semiconductor], TMP47C990E Datasheet - Page 17

• Manufacturer Part Number: TMP47C990E
• Description: CMOS 4-bit Microcontroller
• Manufacturer: TOSHIBA [Toshiba Semiconductor]

TOSHIBA CORPORATION
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Interrupt enable master flip-flop (EIF)
The EIF controls the enable/disable of all interrupts.
When this flip-flop is cleared to “0”, all interrupts are
disabled; when it is set to “1”, the interrupts are
enabled.
When an interrupt is accepted, the EIF is cleared to
“0”, temporarily disabling the acceptance of subse-
quent interrupts.
When the interrupt service program has been exe-
cuted, the EIF is set to “1” by the execution of the
interrupt return instruction [RETI], being put in the
enabled state again.
Set or clear of the EIF in program is performed by
instruction [EICLR IL, r] and [DICLR IL, R], respectively.
The EIF is initialized to “0” during reset.
Interrupt enable register (EIR)
The EIR is a 4-bit register specifies the enable or dis-
able of each interrupt except INT1. An interrupt is
Figure 2-21. Interrupt Controller Block Diagram
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enabled when the corresponding bit of the EIR is “1”,
and an interrupt is disabled when the corresponding
bit of the EIR is “0”. Bit 1 of the EIR (EIR
both IOVF2 and ITMR interrupts.
Read/write on the EIR is performed by executing [SCH
a, EIR] instruction. The EIR initialized to “0” during
reset.
Interrupt latch (IL5 through IL0)
An interrupt latch is provided for each interrupt source.
The IL is set to “1” when an interrupt request is made
to ask the CPU for accepting the interrupt. Each IL is
cleared to “0” upon acceptance of the interrupt. It is
initialized to “0” during reset.
The ILS can be cleared independently by interrupt
latch operation instructions ([EICLR IL, r], [DICLR IL, r],
and [CLR IL, r]) to make them cancel interrupt requests
or initialize by program. When the value of instruction
field (r) is “0”, the interrupt latch is cleared; when the
value is “1”, the IL is held. Note that the ILs cannot be
set by instruction.
TMP47C101/201
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