M16C62_M Datasheet, PDF (428/615 Pages) Renesas Technology Corp – 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M16C/60 SERIES

A-D Converter
Mitsubishi microcomputers
M16C / 62A Group
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
(4) Functions selection
(a) Sample & Hold function
Sample & Hold function samples input voltage when A-D conversion starts and carries out A-D
conversion on the voltage sampled. When A-D conversion starts, input voltage is sampled for 3
cycles of the operation clock. When the Sample & Hold function is selected, set the operation clock
for A-D conversion to 1 MHz or higher.
(b) 8-bit A-D to 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 resolu-
tion and 8-bit resolution are given below:
10-bit resolution (Vref X n / 2¹⁰ ) – (Vref X 0.5 / 2¹⁰ ) (n = 1 to 1023), 0 (n = 0)
8-bit resolution (Vref X n / 2⁸ ) – (Vref X 0.5 / 2¹⁰ ) (n = 1 to 255), 0 (n = 0)
(c) A-D conversion by external trigger
The user can select software or an external pin input to start A-D conversion.
(d) External operation amplifier connection function
The selected A-D convertor pin input voltage can be output from the ANEX0 pin. By connecting an
operation amplifier between the ANEX1 pin and ANEX0 pin when using this function, the input volt-
age to all A-D conversion pins can be amplified with one operation amplifier.
(e) Expanded analog input pins function
A-D conversion can be done for voltage input from either the ANEX0 pin or the ANEX1 pin.
(f) Connecting or cutting Vref
Cutting Vref allows decrease of the current flowing into the A-D converter. To decrease the
microcomputer's power consumption, cut Vref. To carry out A-D conversion, start A-D conversion 1
µs or longer after connecting Vref.
The following are exsamples in which functions (a) through (f) are selected:
• One-shot mode ...................................................................................................................... P2-116
___________
• One-shot mode, trigger by ADTRG ............................................................................................................... P2-118
• One-shot mode, software trigger, expanded analog input ..................................................... P2-120
• One-shot mode, software trigger, external operation amplifier connected ............................ P2-122
• Repeat mode, software trigger .............................................................................................. P2-124
• One-shot sweep mode, software trigger ................................................................................ P2-126
• Repeated sweep mode 0, software trigger ............................................................................ P2-128
• Repeated sweep mode 1, software trigger ............................................................................ P2-130
2-111