
130
8048C–AVR–02/12
ATtiny43U
When this bit is written to one, Auto Triggering of the ADC is enabled. The ADC will start a con-
version on a positive edge of the selected trigger signal. The trigger source is selected by setting
the ADC Trigger Select bits, ADTS in ADCSRB.
Bit 4 – ADIF: ADC Interrupt Flag
This bit is set when an ADC conversion completes and the data registers are updated. The ADC
Conversion Complete Interrupt is executed if the ADIE bit and the I-bit in SREG are set. ADIF is
cleared by hardware when executing the corresponding interrupt handling vector. Alternatively,
ADIF is cleared by writing a logical one to the flag. Beware that if doing a Read-Modify-Write on
ADCSRA, a pending interrupt can be disabled. This also applies if the SBI instruction is used.
Bit 3 – ADIE: ADC Interrupt Enable
When this bit is written to one and the I-bit in SREG is set, the ADC Conversion Complete Inter-
rupt is activated.
Bits 2:0 – ADPS[2:0]: ADC Prescaler Select Bits
These bits determine the division factor between the system clock frequency and the input clock
to the ADC.
16.13.3
ADCL and ADCH – ADC Data Register
16.13.3.1
ADLAR = 0
Table 16-5.
ADC Prescaler Selections
ADPS2
ADPS1
ADPS0
Division Factor
000
2
001
2
010
4
011
8
100
16
101
32
110
64
111
128
Bit
151413121110
9
8
–
ADC9
ADC8
ADCH
ADC7
ADC6
ADC5
ADC4
ADC3
ADC2
ADC1
ADC0
ADCL
765
43
21
0
Read/Write
R
RR
R
Initial Value
0
000
00
0