HD64F3048VTF8 Datasheet, PDF (584/903 Pages) Renesas Technology Corp – Hardware Manual Renesas 8-Bit Single-Chip

Section 15 A/D Converter
15.5 Interrupts
The A/D converter generates an interrupt (ADI) at the end of A/D conversion. The ADI interrupt
request can be enabled or disabled by the ADIE bit in ADCSR.
15.6 Usage Notes
When using the A/D converter, note the following points:
1. Analog Input Voltage Range: During A/D conversion, the voltages input to the analog input
pins should be in the range AV_SS ≤ AN_n ≤ V_REF.
2. Relationships of AV_CC and AV_SS to V_CC and V_SS: AV_CC, AV_SS, V_CC, and V_SS should be related as
follows: AV_SS = V_SS. AV_CC and AV_SS must not be left open, even if the A/D converter is not
used.
3. V_REF Programming Range: The reference voltage input at the V_REF pin should be in the range
V_REF ≤ AV_CC.
Failure to observe points 1, 2, and 3 above may degrade chip reliability.
4. Note on Board Design: In board layout, separate the digital circuits from the analog circuits as
much as possible. Particularly avoid layouts in which the signal lines of digital circuits cross or
closely approach the signal lines of analog circuits. Induction and other effects may cause the
analog circuits to operate incorrectly, or may adversely affect the accuracy of A/D conversion.
The analog input signals (AN₀ to AN₇), analog reference voltage (V_REF), and analog supply
voltage (AV_CC) must be separated from digital circuits by the analog ground (AV_SS). The
analog ground (AV_SS) should be connected to a stable digital ground (V_SS) at one point on the
board.
Rev. 3.00 Sep 27, 2006 page 556 of 872
REJ09B0325-0300