tmp89fm42a TOSHIBA Semiconductor CORPORATION, tmp89fm42a Datasheet - Page 78

• Manufacturer Part Number: tmp89fm42a
• Description: 8 Bit Microcontroller
• Manufacturer: TOSHIBA Semiconductor CORPORATION

RA003
3.3
3.3.1
3.3.2
interrupts (software interrupt, undefined instruction interrupt and watchdog interrupt). Non-maskable interrupts are
accepted regardless of the contents of the EIR.
registers are located at addresses 0x003A, 0x003B, 0x003C, 0x003D in the SFR area, and they can be read and written
by instructions (including read-modify-write instructions such as bit manipulation or operation instructions).
Interrupt Enable Register (EIR)
The interrupt enable register (EIR) enables and disables the acceptance of interrupts, except for the non-maskable
The EIR consists of the interrupt master enable flag (IMF) and the individual interrupt enable flags (EF). These
the IMF to "0" disables the acceptance of all maskable interrupts. Setting the IMF to "1" enables the acceptance
of the interrupts that are specified by the individual interrupt enable flags.
subsequent maskable interrupts. After the interrupt service routine is executed, the stacked data, which was the
status before interrupt acceptance, reloaded on the IMF by return interrupt instruction [RETI]/[RETN].
The IMF is normally set and cleared by [EI] and [DI] instructions respectively. During reset, the IMF is initialized
to "0".
bit of an individual interrupt enable flag to "1" enables acceptance of its interrupt, and setting the bit to "0" disables
acceptance.
accepted until the flags are set to "1".
Interrupt master enable flag (IMF)
Individual interrupt enable flags (EF25 to EF4)
The interrupt master enable flag (IMF) enables and disables the acceptance of all maskable interrupts. Clearing
When an interrupt is accepted, the IMF is stacked and then cleared to "0", which temporarily disables the
The IMF is located on bit 0 in EIRL (Address: 0x03A in SFR), and can be read and written by instructions.
Each of these flags enables and disables the acceptance of its maskable interrupt. Setting the corresponding
During reset, all the individual interrupt enable flags are initialized to "0" and no maskable interrupts are
Note:In the main program, before manipulating the interrupt enable flag (EF), be sure to clear the master
Example:Enables interrupts individually and sets IMF
enable flag (IMF) to "0" (Disable interrupt by DI instruction). Then set the IMF to "1" as required after
operating the EF (Enable interrupt by EI instruction).
In the interrupt service routine, the IMF becomes "0" automatically and need not be cleared to "0" nor-
mally. However, if using multiple interrupt in the interrupt service routine, manipulate the EF before setting
the IMF to "1".
DI
LDW
:
:
EI
(EIRL), 0y1110100010100000
Page 59
;IMF ← 0
;
;
;IMF ← 1
EF15 to EF13, EF11, EF7, EF5 ← 1
Note: IMF should not be set.
TMP89FM42A