Table 2.5.3 Recommended Operating Conditions (When Using A-D Converter) - Renesas 4513 User Manual

4500 series 4-bit single-chip microcomputer

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(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 P4

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.