tmp89fm43l TOSHIBA Semiconductor CORPORATION, tmp89fm43l Datasheet - Page 73

• Manufacturer Part Number: tmp89fm43l
• Description: 8 Bit Microcontroller Tlcs-870/c1 Series
• Manufacturer: TOSHIBA Semiconductor CORPORATION

RA003
Example :Using PUSH and POP instructions
3.5.3
3.5.3.1
SP
PINTxx
the interrupt service routine.
case, acceptable interrupt sources are selectively enabled by the individual interrupt enable flags.
before setting IMF to “1”. As for non-maskable interrupt, keep interrupt service shorter compared with length
between interrupt requests.
IMF) are automatically saved on the stack, but the general purpose registers are not. These registers must be saved
by software if necessary. When multiple interrupt services are nested, it is also necessary to avoid using the same
data memory area for saving registers. The following methods are used to save/restore the general-purpose reg-
isters.
At Acceptance of
Saving/restoring general-purpose registers
A maskable interrupt is not accepted until the IMF is set to “1” even if the maskable interrupt is requested in
In order to utilize nested interrupt service, the IMF must be set to “1” in the interrupt service program. In this
To avoid overloaded nesting, clear the individual interrupt enable flag whose interrupt is currently serviced,
During interrupt acceptance processing, the program counter (PC) and the program status word (PSW, includes
an Interrupt
To save only a specific register, PUSH and POP instructions are available.
Using PUSH and POP instructions
PSW
PC
PC
H
L
PUSH
POP
RETI
Interrupt processing
Figure 3-3 Saving/restoring general-purpose registers
SP
PUSH instruction
At execution of
WA
WA
PSW
PC
PC
W
A
H
L
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; Save WA register
; Restore WA register
; RETURN
SP
POP instruction
At execution of
PSW
PC
PC
H
L
SP
an RETI instruction
At execution of
TMP89FM43L
Address
(Example)
b-4
b-3
b-2
b-1
b