12.3.3
A/D Converter Operation Modes
A/D converter operation modes are shown in table 12.3.
Table 12.3 A/D Converter Operation Modes
Operation
Mode
Reset
AMR
Reset
ADSR
Reset
Retained * Functions Functions Retained Retained Retained Retained Retained
ADRRH
Retained * Functions Functions Retained Retained Retained Retained Retained
ADRRL
Note: * Undefined in a power-on reset.
12.4
Interrupts
When A/D conversion ends (ADSF changes from 1 to 0), bit IRRAD in interrupt request register 2
(IRR2) is set to 1.
A/D conversion end interrupts can be enabled or disabled by means of bit IENAD in interrupt
enable register 2 (IENR2).
For further details see section 3.3, Interrupts.
12.5
Typical Use
An example of how the A/D converter can be used is given below, using channel 1 (pin AN1) as
the analog input channel. Figure 12.3 shows the operation timing.
1. Bits CH3 to CH0 of the A/D mode register (AMR) are set to 0101, making pin AN
input channel. A/D interrupts are enabled by setting bit IENAD to 1, and A/D conversion is
started by setting bit ADSF to 1.
2. When A/D conversion is complete, bit IRRAD is set to 1, and the A/D conversion result is
stored in ADRRH and ADRRL. At the same time ADSF is cleared to 0, and the A/D converter
goes to the idle state.
3. Bit IENAD = 1, so an A/D conversion end interrupt is requested.
4. The A/D interrupt handling routine starts.
5. The A/D conversion result is read and processed.
6. The A/D interrupt handling routine ends.
If ADSF is set to 1 again afterward, A/D conversion starts and steps 2 through 6 take place.
Active
Sleep
Functions Functions Retained Retained Retained Retained Retained
Functions Functions Retained Retained Retained Retained Retained
Sub-
Watch
active
Rev. 6.00, 08/04, page 395 of 628
Sub-
sleep
Standby
the analog
1
Module
Standby