SH7040 Datasheet, PDF (601/923 Pages) Renesas Technology Corp – Renesas 32-Bit Single-Chip RISC Microprocessor SuperH RISC engine Family/SH7040 Series(CPU Core SH-2)

When the DTC or DMAC are activated by an ADI interrupt, the ADF flag is cleared to 0 when the
final specified data register is read.
Table 15.9 High Speed A/D Converter Interrupt Sources
Interrupt Source
ADI
Description
Interrupt caused by conversion end
DTC, DMAC Activation
Possible
15.6 Notes on Use
Take note of the following for the A/D converter.
1. Analog input voltage range
During A/D conversions, see that the voltage applied to the analog input pins AN0–AN7 is
within the range Avss ≤ AN0–AN7 ≤ AVcc.
2. AVcc and AVss input voltages
The AVcc and AVss input voltage must be AVcc = Vcc ± 10%, AVss = Vss. When not using
the A/D converter, use AVcc = Vcc, AVss = Vss. During the standby mode, use V_RAM ≤ Avcc
≤ 5.5V, AVss = Vss. V_RAM is the RAM standby voltage.
3. AVref input voltage
The analog standard voltage AVref (AV_ref) must be Avref ≤ AVcc. When not using the A/D
converter, use AV_ref = Vcc. During the standby mode, use V_RAM ≤ AVref ≤ AVcc. V_RAM is the
RAM standby voltage.
4. Input ports
The time constant for the circuit connecting to the input port must be shorter than the sampling
time of the A/D converter. Input voltage may not be sampled sufficiently when the time
constant of the circuit is long.
5. Conversion start modes
Depending on the PWR bit setting, the demand for A/D conversion will differ for the high-
speed start mode and low-demand conversion mode.
6. Analog input pins handling
Connect a protection circuit as shown in figure 15.14 to prevent analog input pins (AN0–AN7)
from being destroyed due to abnormal voltage from surge, etc. This circuit is also equipped
with a CR filter to control errors due to noise. The circuit shown in the diagram is only an
example and the number of circuits is to be determined by considering the actual condition of
use.
Figure 15.15 shows an equivalent circuit of analog input pins and table 15.10 shows the
specification of the analog input pins.
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