Interrupts; Usage Notes - Hitachi H8S/2646 Hardware Manual

Hitachi 16-bit single-chip microcomputer h8s/2646 series
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16.5

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 can be activated by an ADI interrupt. Having the converted data read by the DTC 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 16-6.
Table 16-6 A/D Converter Interrupt Source
Interrupt Source
ADI
16.6

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
≤ ANn ≤ V
AV
SS
(2) Relation between AV
As the relationship between AV
set AV
= V
, and do not leave the AV
CC
CC
(3) V
input range
ref
The analog reference voltage input at the V
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.
604
Description
Interrupt due to end of conversion
.
ref
, AV
and V
CC
SS
CC
and V
SS
, V
SS
, set AV
= V
. If the A/D converter is not used,
SS
SS
SS
and AV
pins open or no account.
CC
SS
pin set in the range V
ref
DTC Activation
Possible
≤ AV
.
ref
CC

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