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Contents
saved to stack
SP (R7)
SP – 1
SP – 2
SP – 3
SP – 4
Stack
SP + 4
SP + 3
SP + 2
SP + 1
SP (R7)
Even-numbered
address
Prior to start of interrupt
exception handling
After completion of interrupt
exception handling
Notation
PC
H
:
PC
L
:
CCR:
SP:
Upper 8 bits of program counter (PC)
Lower 8 bits of program counter (PC)
Condition code register
Stack pointer
*
Ignored on return from interrupt.
Notes:
CCR
CCR
*
PC
H
PC
L
1.
2.
PC shows the address of the first instruction to be executed upon
return from the interrupt.
Saving and restoring of register contents must always be done
in word size, and must start from an even-numbered address.
Figure 3-4. Stack State after Completion of Interrupt Exception Handling
3.3
Reset State
When the
5(6 pin goes to low level, all processing stops and the system goes to reset state. The
I bit of the condition code register (CCR) is set, masking all interrupts.
After the
5(6 pin is changed externally from low to high level, reset exception handling starts at
the point when the reset conditions are met. For details on reset conditions refer to the applicable
hardware manual.
3.4
Power-Down State
In power-down state the CPU operation is stopped, reducing power consumption. For details see
the applicable hardware manual.
Summary of Contents for H8/300L Series
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