M306V2 Mitsubishi, M306V2 Datasheet - Page 56

• Manufacturer Part Number: M306V2
• Description: SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER with CLOSED CAPTION DECODER and ON-SCREEN DISPLAY CONTROLLER
• Manufacturer: Mitsubishi

56
2.7.9 Rewrite Interrupt Control Register
To rewrite the interrupt control register, do so at a point that does not generate the interrupt request for
that register. If there is possibility of the interrupt request occur, rewrite the interrupt control register after
the interrupt is disabled. The program examples are described as follow:
When a instruction to rewrite the interrupt control register is executed but the interrupt is disabled, the
interrupt request bit is not set sometimes even if the interrupt request for that register has been gener-
ated. This will depend on the instruction. If this creates problems, use the below instructions to change
the register.
Instructions : AND, OR, BCLR, BSET
Example 1:
Example 2:
Example 3:
The reason why two NOP instructions (four when using the HOLD function) or dummy read are inserted
before FSET I in Examples 1 and 2 is to prevent the interrupt enable flag I from being set before the
interrupt control register is rewritten due to effects of the instruction queue.
INT_SWITCH1:
INT_SWITCH2:
INT_SWITCH3:
FCLR
AND.B
NOP
NOP
FSET
FCLR
AND.B
MOV.W MEM, R0
FSET
PUSHC FLG
FCLR
AND.B
POPC
I
#00h, 0055h ; Clear TA0IC int. priority level and int. request bit.
I
I
#00h, 0055h ; Clear TA0IC int. priority level and int. request bit.
I
I
#00h, 0055h ; Clear TA0IC int. priority level and int. request bit.
FLG
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER with CLOSED CAPTION DECODER
; Disable interrupts.
; Four NOP instructions are required when using HOLD function.
; Enable interrupts.
; Disable interrupts.
; Dummy read.
; Enable interrupts.
; Push Flag register onto stack
; Disable interrupts.
; Enable interrupts.
and ON-SCREEN DISPLAY CONTROLLER
MITSUBISHI MICROCOMPUTERS
M306V2ME-XXXFP
M306V2EEFP
Rev. 1.0