RF5C62 データシートの表示（PDF） - RICOH Co.,Ltd.

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RF5C62

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RICOH Co.,Ltd. 

RP/RF/RS5C62

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Questions and Answers

3) Hardware Question 1 : Can the CS pin input be used as it is held low?

Answer 1: The CS pin input can be used as it is held low, provided that the RD and WR pin inputs are

caused to transition from their high to low to high levels to enable read and write operations,

respectively.

Question 2 : May the CS pin input be driven low before or during the process of addressing?

Answer 2: The CS pin input may be driven low before, during, or even after the process of addressing.

Addressing time (tAS) indicates the time required to perform the process of addressing before

the start of read or write operation at which both the RD and CS pin inputs or both the WR and

CS pin inputs are driven low. For more details, see “1. Reading and Writing Operations” in

“USAGE”.

Question 3 : At power-on from 0V, the INTR pin is driven low to output interrupts. What is the cause of

this phenomenon?

Answer 3: At power-on from 0V, the internal registers and counters have indefinite states, causing the

INTR pin to have indefinite states as well. It is necessary, therefore, to provide temporary

masking for interrupts output from the INTR pin and initialize the internal registers and coun-

ters by following the typical software-controlled processes of initialization at power-on (see “11.

1 Initialization at Power-on”). (At power-on from 0V, when the XSTP bit is set to “1” to indicate

the start of oscillation, the TMOUT pin output is turned off.)

Question 4 : As the N-channel open drain pins, may the INTR and TMOUT pins be impressed with

higher voltage than the VDD pin?

Answer 4: As the N-channel open drain pins, the INTR and TMOUT pins, neither of which incorporates a

protective diode for the VDD pin, may be impressed with higher voltage than the VDD pin as

long as it does not exceed the maximum absolute rating of 12V. Their on-state resistance typi-

cally ranges from a few dozen ohms to one hundred ohms (see the graph in 10.10 of “10.

Typical Characteristics”). Their on-state current should preferably range from 10mA to 20mA

or less and must not exceed the maximum current consumption for the package.

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