Datasheet
Analog to Digital Convertor (ADC)
Intel
®
Quark™ microcontroller D2000
January 2016 Datasheet
Document Number: 333577-002EN 385
DPD Deep Power Down mode. ADC is
disabled, calibration state is lost, DVDD
can be off. Enadc=L, enldo=L, dislvl=H.
exit involves waiting for internal voltage
regulator to start-up + recalibration +
dummy conversion cycle. A complete
calibration cycle lasts 81 clock cycles. A
conversion cycle is 14 CLK cycles for 12-
bit resolution.
1 uA @
avdd,
0.5 uA @
dvdd
- 10 usec
+ 95
CLK
cycles.
Writing to
ADC_OP_MODE
register
Whenever exit from deep power down mode or at power up/cold reset, Calibration has
to be performed to reduce offset error from +/- 64 LSB to +/- 2 LSB.
At Power-up / cold reset cycle / transitioning from any other power modes (Deep
Power Down or Power Down or Standby) to normal mode (with calibration or without
calibration), below steps are to be performed:
1. Issue “Normal with/without calibration” command through ADC_OP_MODE
register (OM=”Normal with calibration” or “Normal Without Calibration”, Delay
= 500). Note that Calibration is required if offset error (+/- 64 LSB) has to be
reduced to +/- 2 LSB.
2. Issue “Start Calibration” command by writing ADC_command = Start
calibration in ADC Command Register. This step is optional if calibration is not
required. Optionally “Load Calibration” command can be performed if previous
calibration word is restored.
(AND/OR)
Issue a dummy conversion cycle. Dummy conversion cycle is not required if
“Start calibration” is performed. This is done by:
a. Setting ADC channel sequence table with one entry (channel = 0).
b. Issue ADC Command, with sampling window SW=0, Number of
samples NS = 0 (1 sample), ADC_command = Start Single Shot
Conversion.
3. Use ADC as required.
4. Later on, depending on whether ADC is in use or not, power state can be
lowered to standby/powerdown depending on required power saving and
acceptable entry/exit latency. Before the soc/system is put into “Deep sleep”
power state, ADC has to be put to “Deep Power Down” state.
For converting analog input to digital sample once ADC is in normal/ON power state
with calibration completed, the programming sequence for doing either single shot
conversion or continuous conversion is:
1. Setup ADC Interrupt Enable register.
2. Setup ADC Channel Sequence table based on channel inputs to be converted.
3. Issue ADC Command, with setting sampling window, resolution,
ADC_command = Start Single Conversion or Start Continuous Conversion.
Number of Samples is used to stop single conversion once configured total
number of samples (NS+1) are collected from channels as per channel
sequence table. In case of continuous conversion, interrupt is raised every Ns
number of samples are collected.
A continuous conversion can later be stopped by issuing ADC command with
ADC_command = Stop Continuous conversion.