HD64F7050 RENESAS [Renesas Technology Corp], HD64F7050 Datasheet - Page 476

• Manufacturer Part Number: HD64F7050
• Description: 32-Bit RISC Microcomputer SuperH RISC engine Family/
• Manufacturer: RENESAS [Renesas Technology Corp]

Section 14 A/D Converter
14.5
The A/D converter can generate an A/D conversion end interrupt request (ADI0 or ADI1) upon
completion of A/D conversions. The ADI interrupt can be enabled by setting the ADIE bit in the
A/D control/status register (ADCSR) to 1, or disabled by clearing the ADIE bit to 0.
The DMAC can be activated by an ADI interrupt. In this case an interrupt request is not sent to the
CPU.
When the DMAC is activated by an ADI interrupt, the ADF bit in ADCSR is automatically
cleared when data is transferred by the DMAC.
See section 9.4.3, Example of DMA Transfer between A/D Converter and Internal Memory, for an
example of this operation.
14.6
The following points should be noted when using the A/D converter.
1. Analog input voltage range
2. Relation between AV
3. AV
4. Notes on board design
Rev. 5.00 Jan 06, 2006 page 456 of 818
REJ09B0273-0500
The voltage applied to analog input pins during A/D conversion should be in the range AV
ANn
When using the A/D converter, set AV
converter is not used, set AV
Set AV
If conditions 1, 2, and 3 above are not met, the reliability of the device may be adversely
affected.
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.
Also, digital circuitry must be isolated from the analog input signals (ANn), analog reference
voltage (AV
should be connected at one point to a stable digital ground (V
ref
input range
Interrupt Sources and DMA Transfer Requests
Usage Notes
ref
AV
= 4.5 V to AV
ref
ref
.
), and analog power supply (AV
CC
, AV
CC
when the A/D converter is used, and AV
SS
SS
and V
= V
SS
CC
, and do not leave the AV
, V
CC
SS
= V
CC
CC
±10%, and AV
) by the analog ground (AV
SS
SS
CC
) on the board.
= V
pin open.
ref
SS
. When the A/D
AV
CC
SS
when not used..
). The AV
SS
SS