M16CSLASH1N datasheet(32/238 Pages) RENESAS

32 / 238 page

Rev.1.00

Oct 20, 2004

page 20 of 222

M16C/1N Group

5. Reset

REJ09B0007-0100Z

5. Reset

There are two types of resets; hardware and software. In both cases, operation is the same after the reset.

5.1 Hardware Reset

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A reset is applied using the RESET pin.

When the supply voltage is in the range where operation is guaranteed, a reset is effected by holding the

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reset pin level "L" (0.2VCC max.). When the RESET pin level is then returned to the "H" level, the reset

status is cancelled and program execution resumes from the address in the reset vector table. Since the

value of RAM is indeterminate when power is applied, the initial values must be set. Also, if a reset signal

is input during write to RAM, the access to the RAM will be interrupted. Consequently, the value of the

RAM being written may change to an unintended value due to the interruption.

Note 1: M16C/1N group is delayed more than 2ms until the execution of the program after reset clear in

comparison with M16C/10 group products.

Figures 5.1 and 5.2 show the example reset circuit. Figure 5.3 shows the reset sequence.

5.1.1 When the power supply is stable

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(1)Apply a "L" signal to the RESET pin for at least 200µs.

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(2)Apply a "H" signal to the RESET pin.

5.1.2 Power on

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(1)Apply a "L" signal to the RESET pin.

(2)Let the power supply voltage increase until it meets the recommended operating condition.

(3)Wait for td(P-R) + 200µs or more until the internal power supply stabilizes.

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(4)Apply a "H" signal to the RESET pin.

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