Renesas M16C Series User Manual page 248
16-bit single-chip microcomputer
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Also See for M16C Series:
- Hardware manual (423 pages) ,
- User manual (103 pages) ,
- User manual (501 pages)
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2.6.1.4 Functions selection
(a) Sample & Hold function
The Sample & Hold function samples the input voltage when the A-D conversion starts and carries out
an A-D conversion on the voltage sampled. When the A-D conversion starts, the input voltage is sam-
pled for 3 cycles of the operation clock.
(b) 8-bit A-D and 10-bit A-D switching function
Either 8-bit resolution or 10-bit resolution can be selected. When 8-bit resolution is selected, the 8
higher-order bits of the 10-bit A-D are subjected to A-D conversion. The equations for 10-bit resolution
and 8-bit resolution are given below:
• 10-bit resolution
• 8-bit resolution
(c) A-D conversion by external trigger
The user can select a software trigger or an external pin input to start the A-D conversion.
(d) Connecting or cutting Vref
Cutting Vref decreases of the current flowing into the A-D converter. To decrease the microcomputer's
power consumption, cut Vref. To carry out the A-D conversion, start the A-D conversion 1 µs or more
after connecting Vref.
The following are examples in which functions (a) through (d) are selected:
• One-shot mode
• One-shot mode, trigger by AD
• Repeat mode, software trigger
• Single sweep mode, software trigger
• Repeat sweep mode 0, software trigger
• Repeat sweep mode 1, software trigger
2.6.1.5 Input to A-D converter and direction register
To use the A-D converter, set the direction register of the relevant port to input.
2.6.1.6 Pins related to A-D converter
(a) AN
pin through AN
0
(b) AVcc pin
(c) V
pin
REF
(d) AVss pin
(e) AD
pin
TRG
Rev.1.00 Sep 24, 2003 Page 230 of 360
10
(Vref X n / 2
) – (Vref X 0.5 / 10
8
(Vref X n / 2
) – (Vref X 0.5 / 2
TRG
pin
7
10
)
(n = 1 to 1023), 0 (n = 0)
10
)
(n = 1 to 255), 0 (n = 0)
Section 2.6.2.1
Section 2.6.2.2
Section 2.6.2.3
Section 2.6.2.4
Section 2.6.2.5
Section 2.6.2.6
Input pins of the A-D converter
Power source pin of the analog section
Input pin of reference voltage
GND pin of the analog section
Trigger input pin of the A-D converter
A-D Converter
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