11.2 Interrupt Control and Status Registers

The devices in this family implement the following registers for the interrupt controller:

• INTCON0, INTCON1 Control Registers
• PIRx - Peripheral Interrupt Status Registers
• PIEx - Peripheral Interrupt Enable Registers
• IPRx - Peripheral Interrupt Priority Registers
• IVTBASE Address Registers
• IVTLOCK Register

Global interrupt control functions and external interrupts are controlled from the INTCON0 register. The INTCON1 register contains the status flags for the interrupt controller.

The PIRx registers contain all of the interrupt request flags. Each source of interrupt has a Status bit, which is set by the respective peripherals or an external signal, and is either cleared via software or automatically cleared by hardware upon clearing of the interrupt condition, depending on the peripheral and bit.

The PIEx registers contain all of the interrupt enable bits. These control bits are used to individually enable interrupts from the peripherals or external signals.

The IPRx registers are used to set the interrupt priority level for each source of interrupt. Each user interrupt source can be assigned to either a high or low priority.

The IVTBASE register is user-programmable and is used to determine the start address of the IVT and the IVTLOCK register is used to prevent any unintended writes to the IVTBASE register.

There are two other Configuration bits that control the way the interrupt controller can be configured: The MVECEN and the IVT1WAY bits.

The MVECEN bit determines whether the IVT is used to determine the interrupt priorities. The IVT1WAY bit determines the number of times the IVTLOCKED bit can be cleared and set after a device Reset. See the Interrupt Vector Table Address Calculation section for details.