HD6433802H Datasheet, PDF (77/435 Pages) Hitachi Semiconductor – Single-Chip Microcomputer

3.2.3 Interrupt Immediately after Reset
After a reset, if an interrupt were to be accepted before the stack pointer (SP: R7) was initialized,
PC and CCR would not be pushed onto the stack correctly, resulting in program runaway. To
prevent this, immediately after reset exception handling all interrupts are masked. For this reason,
the initial program instruction is always executed immediately after a reset. This instruction
should initialize the stack pointer (e.g. MOV.W #xx: 16, SP).
3.3 Interrupts
3.3.1 Overview
The interrupt sources include 11 external interrupts (WKP₇ to WKP₀, IRQ₁ to IRQ₀, IRQAEC)
and 7 internal interrupts from on-chip peripheral modules. Table 3.2 shows the interrupt sources,
their priorities, and their vector addresses. When more than one interrupt is requested, the interrupt
with the highest priority is processed.
The interrupts have the following features:
• Internal and external interrupts can be masked by the I bit in CCR. When the I bit is set to 1,
interrupt request flags can be set but the interrupts are not accepted.
• IRQAEC, IRQ₁ to IRQ₀, and WKP₇ to WKP₀ can be set to either rising edge sensing or falling
edge sensing.
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