1. What is meant by an "exception" on a microcomputer/microcontroller, and what are the two kinds of exceptions?
2. (a) List and briefly describe the 4 kinds of events that can cause the MC9S12DP256B microcontroller to be reset?
(b) When a reset is initiated, how does the microcontroller respond?
3. What is the primary difference in the way the microcontroller responds to a reset and the way it responds to an interrupt?
4. (a) What flag in the Condition Code Register (CCR) affects the maskable interrupts?
(b) How that this flag be controlled by C code?
5. If an interrupt request is applied to the IRQ pin on the microcontroller, what two conditions must be present in order for an interrupt to be granted?
(b) Below is a list of steps that the 256B microcontroller performs when the an interrupt request on the IRQ pin is accepted. Put numbers to the left side of these steps to show the order in which they are performed:
• Calculate return address and save on stack, along with values in key registers.
• Start executing instructions in interrupt service routine
• Finish current instruction
• Set "I" bit in Condition Code Register (CRC) to 1, to disable other maskable interrupt requests.
• Set "X" bit in Condition Code Register (CRC) to 1, to temporarily disable XIRQ non-maskable interrupt requests.
• Obtain starting address of interrupt service routine from interrupt vector table.
• Clear instruction queue
(c) From what address(es) in the interrupt vector table does the microcontroller obtain the starting address of the service routine for interrupt requests applied to the IRQ pin?
(d) From what address(es) in the interrupt vector table does the microcontroller obtain the starting address of the service routine for interrupt requests applied to the XIRQ pin?