Panasonic MN101C77C, F77G user manual Padir

Chapter 15 A/D Converter

„A/D Conversion Setup Example by External Interrupt 3

The A/D conversion is started by the external interrupt 3. The analog input pin is set to AN0, the con- verter clock is set to fs/4, and the sample hold time is set to TAD x 6. Then, the A/D conversion complete interrupt is generated.

An example setup procedure, with a description of each step is shown below.

Setup Procedure		Description
(1) Set the analog input pin.	(1) Set the analog input pin that set in (2), to the
PAIMD(x'3F3C')	special function pin by the port A input mode
bp0 : PAIMD0 = 1	register (PAIMD). Also, set no pull-up/pull-
PAPLUD (x'3F4A')	down resistance by the port A pull-up/pull-
bp0 : PAPLUD0 = 0	down resistance control register (PAPLUD).
PADIR (x'3F3A')	Set the analog I/O pin, set in (2), to input
bp0 : PADIR0 = 0	mode by port A direction control register
	(PADIR).
(2) Select the analog input pin.	(2) Select the analog input pin from AN6-0 (PA6-
ANCTR1(x'3FB1')	0) by the ANCHS2-0 flag of the A/D converter
bp2-0 : ANCH2-0 = 000	control register 1 (ANCTR1).
(3) Select the A/D converter clock.	(3) Select the A/D converter clock by the
ANCTR0 (x'3FB0')	ANCK1, ANCK0 flag of the A/D converter
bp5-4 : ANCK1-0 = 01	control register 0 (ANCTR0).
(4) Set the sample hold time.	(4) Set the sample hold time by the ANSH1,
ANCTR0 (x'3FB0')	ANSH0 flag of the A/D converter control
bp7-6 : ANSH1-0 = 01	register 0 (ANCTR0).
(5) Specify the external interrupt 3 valid	(5) Specify the valid edge by the REDG3 flag of the
edge.	external interrupt 3 control register (IRQ3ICR),
IRQ3ICR (x'3FE5')	the EDGSEL3 flag of the both edges interrupt
bp5 : REDG3 = 1	control register (EDGDT).
EDGDT (x'3F8F')	[	Chapter 3. 3-1-4 Interrupt Flag Setup ]
bp3 : EDGSEL3 = 0
(6) Set the interrupt level.	(6) Set the interrupt level by the ADLV1-0 flag of
ADICR (x'3FFA')	the A/D conversion complete interrupt control
bp7-6 : ADLV1-0 = 10	register (ADICR). If any interrupt request flag
	is already set, clear them.

XV - 14 Operation