4513_03 Datasheet, PDF (156/210 Pages) Renesas Technology Corp – 4-BIT SINGLE-CHIP MICROCOMPUTER

APPLICATION
2.5 A-D converter
(5) A-D converter is used at the comparator mode
The analog input voltage is higher than the comparison voltage as a result of comparison, the
contents of ADF flag retains “0,” not set to “1.”
In this case, the A-D interrupt does not occur even when the usage of the A-D interrupt is enabled.
Accordingly, consider the time until the comparator operation is completed, and examine the state
of ADF flag by software. The comparator operation is completed after 8 machine cycles.
(6) Analog input pins
Even when P40/AIN4–P43/AIN7 are set to pins for analog input, they continue to function as P40–P43
I/O. Accordingly, when any of them are used as I/O port P4 and others are used as analog input pins,
make sure to set the outputs of pins that are set for analog input to “1.” Also, the port input function
of the pin functions as an analog input is undefined.
(7) TALA instruction
When the TALA instruction is executed, the low-order 2 bits of register AD is transferred to the high-
order 2 bits of register A, and simultaneously, the low-order 2 bits of register A is “0.”
(8) Recommended operating conditions when using A-D converter
The recommended operating conditions of supply voltage and system clock frequency when using A-
D converter are different from those when not using A-D converter.
Table 2.5.3 shows the recommended operating conditions when using A-D converter.
Table 2.5.3 Recommended operating conditions (when using A-D converter)
Parameter
Condition
Limits
Unit
Min. Typ. Max.
VDD = 4.5 V to 5.5 V (high-speed mode)
0.4
System clock frequency
VDD = 4.0 V to 5.5 V (high-speed mode)
0.4
(at ceramic resonance)
VDD = 2.7 V to 5.5 V (middle-speed mode)
0.4
VDD = 4.5 V to 5.5 V (high-speed mode)
0.4
System clock frequency
Duty
VDD = 4.0 V to 5.5 V (high-speed mode)
0.4
(at external clock input)
40 % to 60 %
VDD = 2.7 V to 5.5 V (middle-speed mode)
0.4
4.2
2.0
4.2 _MHz
3.0
1.0
3.0
4513/4514 Group User’s Manual
2-53