M306V0ME-107FP MITSUBISHI [Mitsubishi Electric Semiconductor], M306V0ME-107FP Datasheet - Page 60

• Manufacturer Part Number: M306V0ME-107FP
• Description: SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER with CLOSED CAPTION DECODER and ON-SCREEN DISPLAY CONTROLLER
• Manufacturer: MITSUBISHI [Mitsubishi Electric Semiconductor]

60
Figure 2.7.7 Operation of saving registers
The operation of saving registers carried out in the interrupt sequence is dependent on whether the
content of the stack pointer, at the time of acceptance of an interrupt request, is even or odd. If the
content of the stack pointer (Note) is even, the content of the flag register (FLG) and the content of the
program counter (PC) are saved, 16 bits at a time. If odd, their contents are saved in two steps, 8 bits at
a time. Figure 2.7.7 shows the operation of the saving registers.
Note: Stack pointer indicated by U flag.
(1) Stack pointer (SP) contains even number
[SP] – 5 (Odd)
[SP] – 4 (Even)
[SP] – 2 (Even)
[SP] – 5 (Even)
[SP] – 3 (Even)
[SP] – 1 (Even)
[SP] – 3(Odd)
[SP] – 1(Odd)
[SP]
(2) Stack pointer (SP) contains odd number
[SP] – 4(Odd)
[SP] – 2(Odd)
[SP]
Note: [SP] denotes the initial value of the stack pointer (SP) when interrupt request is acknowledged.
Address
Address
(Odd)
After registers are saved, the SP content is [SP] minus 4.
(Even)
Flag register
Flag register
Program counter (PC
Program counter (PC
Program counter (PC
Program counter (PC
(FLG
(FLG
Flag register (FLG
Flag register (FLG
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER with CLOSED CAPTION DECODER
Stack area
Stack area
H
H
)
)
counter (PC
counter (PC
Program
Program
L
L
)
)
M
M
L
L
)
)
)
)
H
H
)
)
Sequence in which order
registers are saved
Sequence in which order
registers are saved
Finished saving registers
in two operations.
(3)
(4)
(1)
(2)
(2) Saved simultaneously,
(1) Saved simultaneously,
Finished saving registers
in four operations.
all 16 bits
all 16 bits
Saved simultaneously,
all 8 bits
and ON-SCREEN DISPLAY CONTROLLER
MITSUBISHI MICROCOMPUTERS
M306V0ME-XXXFP
M306V0EEFP
Rev. 1.0