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19.5
Interrupts
The A/D converter generates an A/D conversion end interrupt (ADI) at the end of A/D conversion.
ADI interrupt requests can be enabled or disabled by means of the ADIE bit in ADCSR.
The DTC * and DMAC * can be activated by an ADI interrupt. Having the converted data read by
the DTC * or DMAC * in response to an ADI interrupt enables continuous conversion to be
achieved without imposing a load on software.
The A/D converter interrupt source is shown in table 19-6.
Note: * This function is not available in the H8S/2695.
Table 19-6 A/D Converter Interrupt Source
Interrupt Source
ADI
Note: * This function is not available in the H8S/2695.
19.6
Usage Notes
The following points should be noted when using the A/D converter.
Setting Range of Analog Power Supply and Other Pins:
(1) Analog input voltage range
The voltage applied to analog input pin ANn during A/D conversion should be in the range
AVSS ≤ ANn ≤ Vref.
(2) Relation between AVCC, AVSS and VCC, VSS
As the relationship between AVCC, AVSS and VCC, VSS, set AVSS = VSS. If the A/D
converter is not used, the AVCC and AVSS pins must on no account be left open.
(3) Vref input range
The analog reference voltage input at the Vref pin set in the range Vref ≤ AVCC.
If conditions (1), (2), and (3) above are not met, the reliability of the device may be adversely
affected.
Notes on Board Design: In board design, digital circuitry and analog circuitry should be as
mutually isolated as possible, and layout in which digital circuit signal lines and analog circuit
signal lines cross or are in close proximity should be avoided as far as possible. Failure to do so
may result in incorrect operation of the analog circuitry due to inductance, adversely affecting A/D
conversion values.
876
Description
Interrupt due to end of conversion
DTC * , DMAC * Activation
Possible
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