APPENDIX
Appendix 2. Control registers
b7 b6 b5 b4 b3 b2 b1 b0
A-D control register 1 (Address 1F16
)
0
Bit
0
Bit name
At reset
1
Function
R/W
RW
Reference
12-8
12-9
Single sweep mode/Repeat sweep mode 0
A-D sweep pin select bits
b1 b0
(Valid in the single sweep mode,
repeat sweep mode 0, and
0 0 : Pins AN0 and AN1 (2 pins)
0 1 : Pins AN0 to AN3 (4 pins)
1 0 : Pins AN0 to AN5 (6 pins)
repeat sweep mode 1.)
(Note 1)
1 1 : Pins AN0 to AN7 (8 pins) (Note 2)
1
RW
1
Repeat sweep mode 1
b1 b0
(Note 3)
0 0 : Pin AN0 (1 pin)
0 1 : Pins AN0 and AN1 (2 pins)
1 0 : Pins AN0 to AN2 (3 pins)
1 1 : Pins AN0 to AN3 (4 pins)
A-D operation mode select bit 1
(Used in the repeat sweep mode 0
and repeat sweep mode 1.)(Note 4)
0 : Repeat sweep mode 0
1 : Repeat sweep mode 1
RW
RW
0
2
3
Resolution select bit
0
0
0 : 8-bit resolution mode
1 : 10-bit resolution mode
A-D conversion frequency (φAD) select bit 1
Fix this bit to “0.”
4
5
6
RW
RW
See Table 12.2.1.
0
0
12-9
16-7
VREF connection select bit (Note 5) 0 : Pin VREF is connected.
RW
1 : Pin VREF is disconnected.
–
The value is “0” at reading.
7
0
Notes 1: These bits are invalid in the one-shot and repeat modes. (They may be either “0” or “1.”)
2: When using pin AN7, be sure that the D-A0 output enable bit (bit 0 at address 9616) = “0” (output disabled).
3: Be sure to select the frequently-used analog input pins in the repeat sweep mode 1.
4: Fix this bit to “0” in the one-shot mode, repeat mode, and single sweep mode.
5: When this bit is cleared from “1” to “0,” be sure to start the A-D conversion after an interval of 1 µs or more has elapsed.
6: Writing to each bit of the A-D control register 1 must be performed while the A-D converter halts, regardless of the A-D
operation mode.
b7 b6 b5 b4 b3 b2 b1 b0
A-D control register 2 (Address DB16
)
0
0 0 0
Reference
Bit
0
Bit name
Function
X X X : Pins AN0 to AN7 are selected.
1 0 0 0 : Pin AN8 is selected.
1 0 0 1 : Pin AN9 is selected.
1 0 1 0 : Pin AN10 is selected.
1 0 1 1 : Pin AN11 is selected.
1 1 0 0 : Do not select.
At reset R/W
b3 b2 b1 b0
0
12-8
RW
RW
0
0
Analog input pin select bits 1
(Note 2)
(Note 3)
(Note 4)
(Note 5)
(Note 6)
(Note 1)
1
2
0
0
0
RW
RW
RW
3
1 1 1 1 : Do not select.
7 to 4
Fix these bits to “0000.”
X : They may be either “0” or “1.”
Note 1: When using pins AN0 to AN7, regardless of the A-D operation mode, be sure to fix bit 3 to “0.” Also, pins AN8 to AN11 are
used only in the one-shot mode and repeat mode.
2: Use bits 2 to 0 of A-D control register 0 (address 1E16) for selection of pins AN0 to AN7.
3: When using pin AN8, be sure that the D-A1 output enable bit (bit 1 at address 9616) = “0” (output disabled). Also, be sure not
to use pin CTS2/RTS2.
4: When using pin AN9, be sure not to use pin CTS2/CLK2.
5: When using pin AN10, be sure not to use pin RXD2.
6: When using pin AN11, be sure not to use pin TXD2.
7: Writing to each bit of A-D control register 2 must be performed while the A-D conversion halts, regardless of the A-D
operation mode.
7905 Group User’s Manual Rev.1.0
20-13
RENESAS [ RENESAS TECHNOLOGY CORP ]
