Panasonic MN101C77C, F77G user manual T7ICEDG, T7ICEN

Chapter 7 16-bit Timer

Setup Procedure					Description
(6) Select the capture trigger generation			(6)	Set the T7ICEDG flag of the TM7MD2 register
edge.				to "1" to select the external interrupt valid edge
TM7MD2 (x'3F79')				as a generation source of capture trigger.
bp7	: T7ICEDG	= 1
(7) Set the compare register.			(7)	Set the timer 7 preset register 1 (TM7PR1) to
TM7PR1(x'3F75',x'3F74') = x'FFFF'				x'FFFF'. At that time, the same value is loaded
				to the timer 7 compare register 1 (TM7OC1),
				and the timer 7 binary counter (TM7BC) is
				initialized to x'0000'.
(8) Set the interrupt level.			(8) Set the interrupt level by the IRQ0LV1-0 flag of
IRQ0ICR (x'3FE2')				the IRQ0ICR register. If any interrupt request
bp7-6	: IRQ0LV1-0= 10			flag may be set already, clear them.
				[	Chapter 3 3-1-4. Interrupt Flag Setup ]
(9) Enable the interrupt.			(9)	Enable the interrupt by setting the IRQ0IE flag
IRQ0ICR (x'3FE2')				of the IRQ0ICR register to "1".
bp1	: IRQ0IE	= 1
(10) Enable the capture trigger			(10)	Enable the capture trigger generation by
generation.				setting the T7ICEN flag of the TM7MD2
TM7MD2 (x'3F79')				register to "1".
bp2	: T7ICEN	= 1
(11) Start the timer operation.			(11)	Set the TM7EN flag of the TM7MD1 register to
TM7MD1 (x'3F78')				"1" to start timer 7.
bp4	: TM7EN	= 1

TM7BC counts up from x'0000'. At the timing of the rising edge of the external interrupt 0 input signal, the value of TM7BC is stored to the TM7IC register. And at that time, the pulse width between rising edges of the external interrupt input signal can be measured by reading the value of TM7IC register by the interrupt service routine, and by calculating the margin of the capture values (the values of the TM7IC register).

VII - 38 16-bit Timer Capture