M30222 Datasheet, PDF (165/237 Pages) Mitsubishi Electric Semiconductor – SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER

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Specifications in this manual are tentative and subject to change
MITSUBISHI MICROCOMPUTERS
M30222 Group
Rev. G
A-D Converter
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
(a) Sample and hold
Sample and hold is selected by setting bit 0 of the A-D control register 2 (address 03D416) to “1”. When
sample and hold is selected, the speed of conversion increases. As a result, a 28 fAD cycle is achieved with 8-
bit resolution and 33 fAD with 10-bit resolution. Sample and hold can be selected in all modes. However, in all
modes, be sure to specify before starting A-D conversion whether sample and hold is to be used.
(b) Extended analog input pins
In one-shot mode and repeat mode, the input via the extended analog input pins ANEX0 and ANEX1 can also
be converted.
When bit 6 of the A-D control register 1 (address 03D716) is “1” and bit 7 is “0”, input via ANEX0 is con-
verted. The result of conversion is stored in A-D register 0.
When bit 6 of the A-D control register 1 (address 03D716) is “0” and bit 7 is “1”, input via ANEX1 is con-
verted. The result of conversion is stored in A-D register 1.
(c) External operation amp connection mode
In this mode, multiple external analog inputs via the extended analog input pins, ANEX0 and ANEX1, can be
amplified together by just one operation amp and used as the input for A-D conversion.
When bit 6 of the A-D control register 1 (address 03D716) is “1” and bit 7 is “1”, input via AN0 to AN7 is output
from ANEX0. The input from ANEX1 is converted from analog to digital and the result stored in the corre-
sponding A-D register. The speed of A-D conversion depends on the response of the external operation amp.
Do not connect the ANEX0 and ANEX1 pins directly. Figure 1.134 is an example of how to connect the pins
in external operation amp mode.
Resistor ladder
Analog
input
AN0
AN1
AN2
AN3
AN4
AN5
AN6
AN7
Successive conversion register
ANEX0
ANEX1
External op-amp
Fig. 1.134. Example of external op-amp connection mode
Comparator
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