239
AT90PWM216/316 [DATASHEET]
7710H–AVR–07/2013
20.8.5
Digital Input Disable Register 0 – DIDR0
Bit 7:0 – ADC7D..ADC0D: ACMP2:1 and ADC7:0 Digital Input Disable
When this bit is written logic one, the digital input buffer on the corresponding ADC pin is disabled. The corre-
sponding PIN Register bit will always read as zero when this bit is set. When an analog signal is applied to the
ADC7..0 pin and the digital input from this pin is not needed, this bit should be written logic one to reduce power
consumption in the digital input buffer.
20.8.6
Digital Input Disable Register 1– DIDR1
Bit 5:0 – ACMP0D, AMP0+D, AMP0-D, ADC10D..ADC8D: ACMP0, AMP1:0 and ADC10:8 Digital Input
Disable
When this bit is written logic one, the digital input buffer on the corresponding ADC pin is disabled. The corre-
sponding PIN Register bit will always read as zero when this bit is set. When an analog signal is applied to an
analog pin and the digital input from this pin is not needed, this bit should be written logic one to reduce power con-
sumption in the digital input buffer.
20.9
Amplifier
The AT90PWM216/316 features two differential amplified channels with programmable 5, 10, 20, and 40 gain
stage. Despite the result is given by the 10 bit ADC, the amplifier has been sized to give a 8bits resolution.
Because the amplifier is a switching capacitor amplifier, it needs to be clocked by a synchronization signal called in
this document the amplifier synchronization clock. The maximum frequency of this clock is 250kHz.
To ensure an accurate result, the amplifier input needs to have a quite stable input value at the sampling point dur-
ing at least 4 Amplifier synchronization clock periods.
154) or to the internal clock CK
ADC equal to eighth the ADC clock frequency. In case the synchronization is done by
the ADC clock divided by 8, this synchronization is done automatically by the ADC interface in such a way that the
sample-and-hold occurs at a specific phase of CK
ADC2. A conversion initiated by the user (i.e., all single conver-
sions, and the first free running conversion) when CK
ADC2 is low will take the same amount of time as a single
ended conversion (13 ADC clock cycles from the next prescaled clock cycle). A conversion initiated by the user
when CK
ADC2 is high will take 14 ADC clock cycles due to the synchronization mechanism.
The normal way to use the amplifier is to select a synchronization clock via the AMPxTS1:0 bits in the AMPxCSR
register. Then the amplifier can be switched on, and the amplification is done on each synchronization event. The
amplification is done independently of the ADC.
In order to start an amplified Analog to Digital Conversion on the amplified channel, the ADMUX must be config-
The ADC starting is done by setting the ADSC (ADC Start conversion) bit in the ADCSRA register.
Bit
76543210
ADC7D
ADC6D
ADC5D
ADC4D
ADC3D
ACMPM
ADC2D
ACMP2D
ADC1D
ADC0D
DIDR0
Read/Write
R/W
Initial Value
00000000
Bit
76543210
-
ACMP0D
AMP0PD
AMP0ND
ADC10D
ACMP1D
ADC9D
AMP1PD
ADC8D
AMP1ND
DIDR1
Read/Write
-
R/W
Initial Value
00000000