cop8cfe9 National Semiconductor Corporation, cop8cfe9 Datasheet - Page 34

• Manufacturer Part Number: cop8cfe9
• Description: 8-bit Cmos Flash Microcontroller With 8k Memory, Virtual Eeprom, And 10-bit A/d
• Manufacturer: National Semiconductor Corporation

www.national.com
8.0 A/D Converter
CHANNEL SELECT
This 4-bit field selects one of sixteen channels to be the V
The mode selection and the mux output determine the V
input. When MUX = 0, all sixteen channels are available, as
shown in Table 18 . When MUX = 1, only fourteen channels
are available, as shown in Table 19 .
ADCH3 ADCH2 ADCH1 ADCH0
ADCH3
Bit 7
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
Channel Select
TABLE 18. A/D Converter Channel Selection when the Multiplexor Output is Disabled
ADCH2
TABLE 17. ENAD
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
Select Bits
Mode Select Mux/Out Prescale
ADMOD
(Continued)
ADCH1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
MUX
PSC
ADCH0
ADBSY
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
Busy
Bit 0
IN+
IN-
.
34
Single Ended Mode
All port pins which are used, in the application, in A/D opera-
tions must be configured as high-impedance inputs. If the
ports are configured as outputs or inputs with weak pull-up
there will be a conflict between the analog signal and the
digitally driven output.
Mode Select
Channel No.
ADMOD = 0
10
11
12
13
14
15
0
1
2
3
4
5
6
7
8
9
Channel Pairs (+, −)
Differential Mode
Mode Select
ADMOD = 1
12, 13
13, 12
14, 15
15, 14
10, 11
11, 10
0, 1
1, 0
2, 3
3, 2
4, 5
5, 4
6, 7
7, 6
8, 9
9, 8
Mux Output
Disabled
MUX
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0