UPD78F1502AGK-GAK-AX Datasheet, PDF (411/1031 Pages) Renesas Technology Corp – 16-Bit Single-Chip Microcontrollers

78K0R/Lx3
CHAPTER 10 12-BIT A/D CONVERTER (μ PD78F150xA),
10-BIT A/D CONVERTER (μ PD78F151xA)
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(4) Analog reference voltage control register (ADVRC)
This register is used to select the reference voltage supplies of the A/D and D/A converters, control the operation of the input
gate voltage boost circuit for the A/D converter, and control the voltage reference (VR) operation.
The electrical specifications of the A/D converter can be maintained even during low-voltage operation thanks to the
operation of the input gate voltage boost circuit for the A/D converter.
ADVRC can be set by a 1-bit or 8-bit memory manipulation instruction.
Reset signal generation clears this register to 00H.
Figure 10-9. Format of Analog Reference Voltage Control Register (ADVRC)
Address: FFF36H After reset: 00H
Symbol
7
6
ADVRC ADREF ^Note
0
R/W
5
0
4
3
2
0
VRSEL ^Note
0
1
VRGV ^Note
0
VRON ^Note
ADREF ^Note
0
1
Negative reference voltage supply selection of A/D converter selection
AVSS
AVREFM (external voltage reference input)
VRSEL ^Note
VRGV
VRON ^Note
0
0
0
0
1
0
1
0
0
1
0
1
1
1
0
1
1
1
Other than the above
Positive
reference voltage
supplies selection
of A/D and D/A
converters
Operation
control of
voltage
reference
AVREFP
(external voltage
reference input)
Stops
operation
(Hi-Z)
VREFOUT
(voltage
reference output)
Stops
operation
(pull-down
output)
Enables
operation
Stops
operation
(pull-down
output)
Enables
operation
Setting prohibited
Output
voltage
selection of
voltage
reference
2.5 V
2.0 V
2.5 V
2.5 V
2.0 V
2.0 V
Operation
control of input
gate voltage
boost circuit for
A/D converter
Relationship with
the conversion
mode used
Stops
operation
Can be set in
normal mode 1.
Enables
operation
Can be set in
normal mode 2
or low voltage
mode.
Stops
−
operation
Enables
operation
Can be set in
normal mode 2
or low voltage
mode.
−
Can be set in
normal mode 2
or low voltage
mode.
Note These bits can be set only for μ PD78F150xA. They are fixed “0” for μ PD78F151xA.
Caution 1. When using the A/D converter in normal mode 2 (LV1 = 0, LV0 = 1) or low voltage mode (LV1 = 1,
LV0 = 0), enable the input gate voltage boost circuit for the A/D converter by using the analog
reference voltage control register (ADVRC), and then set ADCE and ADCS to 1. After the voltage
boost circuit stabilization time (10 μs) passes after the input gate voltage boost circuit for the A/D
converter has been enabled, set ADCS to 1.
R01UH0004EJ0501 Rev.5.01
395
Jun 20, 2011