Datasheet

© 2010 Microchip Technology Inc. DS70141F-page 135
dsPIC30F3010/3011
19.9 Module Power-Down Modes
The module has three internal power modes. When the
ADON bit is ‘1’, the module is in Active mode; it is fully
powered and functional. When ADON is ‘0’, the module
is in Off mode. The digital and analog portions of the
circuit are disabled for maximum current savings. In
order to return to the Active mode from Off mode, the
user must wait for the ADC circuitry to stabilize.
19.10 ADC Operation During CPU Sleep
and Idle Modes
19.10.1 ADC OPERATION DURING CPU
SLEEP MODE
When the device enters Sleep mode, all clock sources
to the module are shut down and stay at logic ‘0’.
If Sleep occurs in the middle of a conversion, the
conversion is aborted. The converter will not continue
with a partially completed conversion on exit from
Sleep mode.
Register contents are not affected by the device
entering or leaving Sleep mode.
The ADC module can operate during Sleep mode if the
ADC clock source is set to RC (ADRC = 1). When the
RC clock source is selected, the ADC module waits
one instruction cycle before starting the conversion.
This allows the SLEEP instruction to be executed,
which eliminates all digital switching noise from the
conversion. When the conversion is complete, the
DONE bit will be set and the result loaded into the
ADCBUF register.
If the ADC interrupt is enabled, the device will wake-up
from Sleep. If the ADC interrupt is not enabled, the
ADC module will then be turned off, although the
ADON bit will remain set.
19.10.2 A/D OPERATION DURING CPU IDLE
MODE
The ADSIDL bit selects if the module will stop on Idle or
continue on Idle. If ADSIDL = 0, the module will
continue operation on assertion of Idle mode. If
ADSIDL = 1, the module will stop on Idle.
19.11 Effects of a Reset
A device Reset forces all registers to their Reset state.
This forces the ADC module to be turned off, and any
conversion and acquisition sequence is aborted. The
values that are in the ADCBUF registers are not
modified. The A/DC Result register will contain
unknown data after a Power-on Reset.
19.12 Output Formats
The ADC result is 10 bits wide. The data buffer RAM is
also 10 bits wide. The 10-bit data can be read in one of
four different formats. The FORM<1:0> bits select the
format. Each of the output formats translates to a 16-bit
result on the data bus.
Write data will always be in right justified (integer)
format.
FIGURE 19-4: ADC OUTPUT DATA FORMATS
RAM Contents: d09 d08 d07 d06 d05 d04 d03 d02 d01 d00
Read to Bus:
Signed Fractional (1.15) d09
d08d07d06d05d04d03d02d01d00000000
Fractional (1.15)d09d08d07d06d05d04d03d02d01d00000000
Signed Integer d09 d09 d09 d09 d09 d09 d09 d08 d07 d06 d05 d04 d03 d02 d01 d00
Integer 0 0 0 0 0 0 d09 d08 d07 d06 d05 d04 d03 d02 d01 d00