Datasheet

323
7593L–AVR–09/12
AT90USB64/128
26.9.2 ADCSRA – ADC Control and Status Register A
• Bit 7 – ADEN: ADC Enable
Writing this bit to one enables the ADC. By writing it to zero, the ADC is turned off. Turning the
ADC off while a conversion is in progress, will terminate this conversion.
• Bit 6 – ADSC: ADC Start Conversion
In Single Conversion mode, write this bit to one to start each conversion. In Free Running mode,
write this bit to one to start the first conversion. The first conversion after ADSC has been written
after the ADC has been enabled, or if ADSC is written at the same time as the ADC is enabled,
01000
N/A
(ADC0 / ADC0 / 10x)
01001 ADC1 ADC0 10×
01010 (ADC0 / ADC0 / 200x)
01011 ADC1 ADC0 200×
01100 (Reserved - ADC2 / ADC2 / 10x)
01101 ADC3 ADC2 10×
01110 (ADC2 / ADC2 / 200x)
01111 ADC3 ADC2 200×
10000 ADC0 ADC1 1×
10001 (ADC1 / ADC1 / 1x)
10010 ADC2 ADC1 1×
10011 ADC3 ADC1 1×
10100 ADC4 ADC1 1×
10101 ADC5 ADC1 1×
10110 ADC6 ADC1 1×
10111 ADC7 ADC1 1×
11000 ADC0 ADC2 1×
11001 ADC1 ADC2 1×
11010 (ADC2 / ADC2 / 1x)
11011 ADC3 ADC2 1×
11100 ADC4 ADC2 1×
11101 ADC5 ADC2 1×
11110 1.1V (V
Band Gap
)
N/A
11111 0V (GND)
Table 26-4. Input channel and gain selections. (Continued)
MUX4..0 Single ended input Positive differential input Negative differential input Gain
Bit 76543210
ADEN ADSC ADATE ADIF ADIE ADPS2 ADPS1 ADPS0 ADCSRA
Read/write R/W R/W R/W R/W R/W R/W R/W R/W
Initial value00000000