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CHAPTER 12 A/D CONVERTER
User’s Manual U19780EJ2V0UD
325
(7) 8-bit A/D conversion result register (ADCRH)
The A/D conversion result is loaded from the successive approximation register to this register each time A/D
conversion is completed, and the ADCRH register stores the higher 8 bits of the A/D conversion result.
(8) Controller
This circuit controls the conversion time of an input analog signal that is to be converted into a digital signal, as well
as starting and stopping of the conversion operation. When A/D conversion has been completed, this controller
generates INTAD.
(9) AV
DD
pin
This pin inputs a power to the A/D converter. When one or more of the pins of ports 2 and 8 are used as the digital
port pins, make AV
DD
the same potential as V
DD
.
(10) AV
SS
pin
This is the ground potential pin of the A/D converter. Always use this pin at the same potential as that of the V
SS
pin
even when the A/D converter is not used.
In the 48-pin versions of 78K0/KC3-A, the ground potential (AV
SS
) can also be used as the negative reference voltage
for the A/D converter (AD
REFM
). Clear AVREF bit of ADVRC register to 0 when using AV
SS
as AD
REFM
.
(11) AD
REFP
pin
Note 1
This pin is used to input the external reference voltage (AV
REFP
).
The analog signal input to ANI0 to ANI6, ANI8 to ANI11, and ANI15 are converted into a digital signal, based on the
voltage
Note 2
applied across AV
REFP
and AV
REFM
.
(12) AD
REFM
pin
Note 2
This pin is used to input the external reference voltage (AV
REFM
).
To use AV
REFM
as the negative reference voltage for the A/D converter (AD
REFM
), set the ADREF bit of the ADVRC
register to 1.
Notes 1.
As the AV
REFM
and AV
REFP
are not mounted on 78K0/KB2-A, replace AV
REFP
with AV
REF
, respectively.
2.
In the 78K0/KB2-A, this is the voltage that is applied between AV
REF
and AV
SS
.
Remark
78K0/KB2-A: ANI0 to ANI5, ANI8 to ANI11
78K0/KC2-A: ANI0 to ANI6, ANI8 to ANI11, ANI15