Panasonic MN101C77C, F77G user manual IRQ4SEL, External interrupt 4 source to the port 6 key

Chapter 3 Interrupts

■Key Input Interrupt Setup Example (External interrupt 4)

After P60 to P63 of port 6 are set to key input pins and key is input (low level), the external interrupt 4 (IRQ4) is generated. An example setup procedure, with a description of each step is shown below.

	Setup Procedure				Description
(1)	Set the key input pin to input.			(1) Set the P6DIR3-0 flag of the port 6 direction
	P6DIR(x'3F36')			control register (P6DIR) to "0000" to set P60 to
	bp3-0	: P6DIR3-0	= 0000	P63 pins to input pins.
(2)	Set the pull-up resistance.			(2) Set the P6PLU 3-0 flag of the port 6 pull-up
	P6PLU (x'3F46')			resistance control register (P6PLU) to"1111"
	bp3-0	: P6PLU3-0 = 1111		to add the pull-up resistance to P60 to
				P63 pins.
(3)	Select the key input interrupt.			(3) Set the IRQ4SEL flag of the port 6 key interrupt
	P6IMD (x'3F3E')			control register (P6IMD) to "1" to select the
	bp7	: IRQ4SEL	= 1	external interrupt 4 source to the port 6 key
				interrupt.
(4)	Select the key input pin.			(4) Set the P6KYEN 2-1 flag of the port 6 key
	P6IMD (x'3F3E')			interrupt control register (P6IMD) to "11" to
	bp1-0	: P6KYEN2-1= 11		set P60 to P63 pins to key input pins.
(5)	Set the interrupt level.			(5) Set the interrupt level by the IRQ4LV1-0 flag
	IRQ4ICR (x'3FE6')			of the IRQ4ICR register.
	bp7-6	: IRQ4LV1-0= 10
				If the interrupt request flag has been already
				set, clear the it.
				[	Chapter 3 3-1-4. Interrupt flag setup ]
(6)	Enable the interrupt.			(6) Set the IRQ4IE flag of the IRQ4ICR register
	IRQ4ICR (x'3FE6')			to "1" to enable the interrupt.
	bp1	: IRQ4IE	= 1

Note : The above (3) and (4) are set at the same time.

If there is at least one input signal, from the P60 to P63 pins, shows low level, the external interrupt 4 is generated at the falling edge.

The setup of the key input should be done before the interrupt is enabled.

III- 50 External Interrupts