ATxmega128D4-AU ATMEL [ATMEL Corporation], ATxmega128D4-AU Datasheet - Page 122

• Manufacturer Part Number: ATxmega128D4-AU
• Description: 8/16-bit Atmel XMEGA D4 Microcontroller
• Manufacturer: ATMEL [ATMEL Corporation]

8135L–AVR–06/12
5. ADC gain stage output range is limited to 2.4V
6. ADC Event on compare match non-functional
7.
8. Bandgap measurement with the ADC is non-functional when VCC is below 2.7V
9. Accuracy lost on first three samples after switching input to ADC gain stage
None, avoid using the ADC in the above configurations in order to prevent increased INL
error. Use the ADC in signed mode also for single ended measurements.
The amplified output of the ADC gain stage will never go above 2.4V, hence the differential
input will only give correct output when below 2.4V/gain. For the available gain settings, this
gives a differential input range of:
Problem fix/Workaround
Keep the amplified voltage output from the ADC gain stage below 2.4V in order to get a cor-
rect result, or keep ADC voltage reference below 2.4V.
ADC signalling event will be given at every conversion complete even if Interrupt mode (INT-
MODE) is set to BELOW or ABOVE.
Problem fix/Workaround
Enable and use interrupt on compare match when using the compare function.
ADC propagation delay is not correct when 8x -64x gain is used
The propagation delay will increase by only one ADC clock cycle for 8x and 16x gain setting,
and 32x and 64x gain settings.
Problem fix/Workaround
None
The ADC can not be used to do bandgap measurements when VCC is below 2.7V.
Problem fix/Workaround
None.
Due to memory effect in the ADC gain stage, the first three samples after changing input
channel must be disregarded to achieve 12-bit accuracy.
Problem fix/Workaround
Run three ADC conversions and discard these results after changing input channels to ADC
gain stage.
–
–
–
–
–
–
–
16x
32x
64x
1x
2x
4x
8x
gain:
gain:
gain:
gain:
gain:
gain:
gain:
300
150
2.4
1.2
0.6
75
38
V
V
V
mV
mV
mV
mV
XMEGA D4
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