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M16C/28 Group
Under development Preliminary specification
Specifications in this manual are tentative and subject to change.
15. A-D Converter
Rev.0.60 2004.02.01
page 204 of N
REJ09B0047-0060Z
15. A-D Converter
The microcomputer contains one A-D converter circuit based on 10-bit successive approximation method
configured with a capacitive-coupling amplifier. The analog inputs share the pins with P100 to P107 (AN0 to
____________
AN7), P00 to P07 (AN00 to AN07), and P10 to P13, P93, P95 to P97 (AN20 to AN27). Similarly, ADTRG input
shares the pin with P15. Therefore, when using these inputs, make sure the corresponding port direction
bits are set to “0” (= input mode). Note that P10 to P13, P93, P95 to P97 (AN20 to AN27) are available only in
the 80-pin package.
When not using the A-D converter, set the VCUT bit to “0” (= VREF unconnected), so that no current will flow
from the VREF pin into the resistor ladder, helping to reduce the power consumption of the chip.
The A-D conversion result is stored in the ADi register bits for ANi, AN0i, and AN2i pins (i = 0 to 7).
Table 15.1 shows the A-D converter performance. Figure 15.1 shows the A-D converter block diagram
and Figures 15.2 to 15.4 show the A-D converter associated with registers.
Item
Performance
A-D Conversion Method
Successive approximation (capacitive coupling amplifier)
Analog Input Voltage (Note 1)
0V to AVCC (VCC)
Operating Clock fAD (Note 2)
fAD/divided-by-2 or fAD/divided-by-3 or fAD/divided-by-4 or fAD/divided-by-6
or fAD/divided-by-12 or fAD
Resolution
8-bit or 10-bit (selectable)
Integral Nonlinearity Error When AVCC = VREF = 5V
With 8-bit resolution:
±2LSB
With 10-bit resolution
- AN0 to AN7 input :
±3LSB
- AN00 to AN07 input and AN20 to AN27 input :
±7LSB
When AVCC = VREF = 3.3V
With 8-bit resolution:
±2LSB
With 10-bit resolution
- AN0 to AN7 input :
±5LSB
- AN00 to AN07 input and AN20 to AN27 input :
±7LSB
Operating Modes
One-shot mode, repeat mode, single sweep mode, repeat sweep mode 0, repeat
sweep mode 1, simultaneous sample sweep mode and delayed trigger mode 0,1
Analog Input Pins
8 pins (AN0 to AN7) + 8 pins (AN00 to AN07) + 8 pins (AN20 to AN27)
(80pin-ver.)
8 pins (AN0 to AN7) + 4 pins (AN00 to AN03) + 1 pin (AN24)
(64pin-ver.)
Conversion Speed Per Pin
Without sample and hold function
8-bit resolution: 49 fAD cycles, 10-bit resolution: 59 fAD cycles
With sample and hold function
8-bit resolution: 28 fAD cycles, 10-bit resolution: 33 fAD cycles
Table 15.1 A-D Converter Performance
Note 1: Not dependent on use of sample and hold function.
Note 2: Set the fAD frequency to 10 MHz or less.
Without sample-and-hold function, set the fAD frequency to 250kHZ or more.
With the sample and hold function, set the fAD frequency to 1MHZ or more.