Datasheet

150
7701F–AVR–10/12
Atmel ATtiny24/44/84 [Preliminary]
Notes: 1. See Table 18-5 on page 151 for details.
2. “Temperature Measurement” on page 148
3. For offset calibration only.See Table 18-5 on page 151 and “ADC Operation” on page 138
See Table 18-5 on page 151 for details of selection of differential input channels as well as
selection of offset calibration channels. The MUX0 bit works as a gain selection bit for differen-
tial channels, as shown in Table 18-5 on page 151. When the MUX0 bit is cleared (zero) 1x
gain is selected, and when it is set (one) 20x gain is selected. For normal differential channel
pairs, the MUX5 bit works as a polarity reversal bit. Toggling of the MUX5 bit reverses the pos-
itive and negative channel orientation.
For offset calibration purposes, the offset of certain differential channels can be measured by
selecting the same input for both negative and positive input. This calibration can be done for
ADC0, ADC3, and ADC7.
“ADC Operation” on page 138 describes offset calibration in a more
detailed manner.
Table 18-4. Single Ended Input Channel Selections.
Single Ended Input MUX5..0
ADC0 (PA0) 000000
ADC1 (PA1) 000001
ADC2 (PA2) 000010
ADC3 (PA3) 000011
ADC4 (PA4) 000100
ADC5 (PA5) 000101
ADC6 (PA6) 000110
ADC7 (PA7) 000111
Reserved for differential channels
(1)
001000 - 011111
0V (AGND) 100000
1.1V (I Ref) 100001
ADC8
(2)
100010
Reserved for offset calibration
(3)
100011 - 100111
Reserved for reversal differential channels
(1)
101000 - 111111