25 A/D CONVERTER (ADC10)
25-2
Seiko Epson Corporation
S1C33L26 TECHNICAL MANUAL
ADC10 Input Pins
25.2
Table 25.2.1 lists the A/D converter input pins.
2.1 List of A/D Converter Input Pins
Table 25.
Pin name
I/O
Qty
Function
AIN[5:0]
I
6
Analog signal input pins AIN0 (Ch.0) to AIN5 (Ch.5)
Input the analog signals to be A/D converted. The analog input voltage AV
IN
must
be within the range of V
SS
≤
AV
IN
≤
AV
DD
.
#ADTRIG
I
1
External trigger input pin
Input a trigger signal to start A/D conversion from an external source.
AV
DD
–
1
Analog power-supply pin
Always supply the HV
DD
voltage even if the A/D converter is not used.
The A/D converter input pins (AIN[5:0], #ADTRIG) are shared with I/O ports and are initially set as general pur-
pose I/O port pins. The pin functions must be switched using the port function select bits to use the general purpose
I/O port pins as A/D converter input pins.
For detailed information on pin function switching, see the “I/O Ports (GPIO)” chapter.
Note: The ADC10 converts the digital values input to the P70, P71, P72, P73, P74, and P75 as analog
inputs even if these ports are configured as general-purpose input ports by the port function se-
lect bits.
A/D Converter Settings
25.3
Make the following settings before starting A/D conversion.
(1) Set the analog input pins. See Section 25.2.
(2) Set the A/D conversion clock.
(3) Select the A/D conversion start and end channels.
(4) Select the A/D conversion mode.
(5) Select the A/D conversion trigger source.
(6) Set the sampling time.
(7) Select the conversion result storing mode.
(8) When using A/D converter interrupts, set interrupt conditions. See Section 25.5.
Note: Make sure the A/D converter is disabled (ADEN/ADC10_CTL register = 0) before changing the
above settings. Changing the settings while the A/D converter is enabled may cause a malfunc-
tion.
A/D Conversion Clock Setting
25.3.1
To use the A/D converter, the clocks used in the A/D converter must be supplied by turning on the peripheral mod-
ule clock (PCLK1) output from the clock management unit (CMU) and the PCLK1 division clocks output from the
Prescaler (PSC Ch.0). For more information on clock control, see the “Clock Management Unit (CMU)” and “Pr-
escaler (PSC)” chapters.
The A/D conversion clock can be selected from the 15 PCLK1 division clocks supplied by the Prescaler. Use
ADDF[3:0]/ADC10_CLK register for this selection as shown in Table 25.3.1.1.
Notes: • For the A/D conversion clock frequency range that can be used for this A/D converter, see “A/D
Converter Characteristics” in the “Electrical Characteristics” chapter.
• Do not start an A/D conversion when the clock output from the prescaler is turned off, and do
not turn off the prescaler's clock output when an A/D conversion is underway. This may cause
the A/D converter to operate erratically.