Datasheet

Table Of Contents
Section 20 A/D Converter
Rev. 2.00 Jul. 04, 2007 Page 448 of 692
REJ09B0309-0200
20.5 Example of 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 20.3 shows the operation timing.
1. Bits CH3 to CH0 in the A/D mode register (AMR) are set to 0101, making pin AN1
the
analog 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 completed, bit IRRAD is set to 1, and the A/D conversion result is
stored in ADRR. At the same time bit 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 bit ADSF is set to 1 again afterward, A/D conversion starts and steps 2 through 6 take place.
Figures 20.4 and 20.5 show flowcharts of procedures for using the A/D converter.