4524_M Datasheet, PDF(238/310 Page) Renesas Technology Corp – 4-BIT CISC SINGLE-CHIP MICROCOMPUTER 720 FAMILY / 4500 SERIES

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4524_M Datasheet, PDF (238/310 Pages) Renesas Technology Corp – 4-BIT CISC SINGLE-CHIP MICROCOMPUTER 720 FAMILY / 4500 SERIES

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4524 Group

APPLICATION

2.7 Reset

â¢ Key-on wakeup control register K0 ..........................................0.....0.....0.....0..

â¢ Key-on wakeup control register K1 ..........................................0.....0.....0.....0..

â¢ Key-on wakeup control register K2 ..........................................0.....0.....0.....0..

â¢ Pull-up control register PU0 ......................................................0.....0.....0.....0..

â¢ Pull-up control register PU1 ......................................................0.....0.....0.....0..

â¢ Port output structure control register FR0 ..............................0.....0.....0.....0..

â¢ Port output structure control register FR1 ..............................0.....0.....0.....0..

â¢ Port output structure control register FR2 ..............................0.....0.....0.....0..

â¢ Port output structure control register FR3 ..............................0.....0.....0.....0..

â¢ Carry flag (CY) ...........................................................................................0..

â¢ Register A ....................................................................................0.....0.....0.....0..

â¢ Register B ....................................................................................0.....0.....0.....0..

â¢ Register D ........................................................................................â......â.....â..

â¢ Register E ................................................................â.....â....â.....â.....â.....â......â.....â..

â¢ Register X ....................................................................................0.....0.....0.....0..

â¢ Register Y ....................................................................................0.....0.....0.....0..

â¢ Register Z ..............................................................................................â.....â..

â¢ Stack pointer (SP) ...........................................................................1.....1.....1..

â¢ Operation source clock ............................ On-chip oscillator (operating)

â¢ Ceramic resonator circuit ........................................................... Operating

â¢ RC oscillation circuit ............................................................................ Stop

â¢ Quartz-crystal oscillator .............................................................. Operating

Fig. 2.7.4 Internal state at reset

âââ represents undefined.

2.7.3 Notes on use

(1) Register initial value

The initial value of the following registers are undefined after system is released from reset. After

system is released from reset, set initial values.

â¢ Register Z (2 bits)

â¢ Register D (3 bits)

â¢ Register E (8 bits)

(2) Power-on reset

Reset can be automatically performed at power on (power-on reset) by the built-in power-on reset

circuit. When the built-in power-on reset circuit is used, the time for the supply voltage to rise from

0 V to the minimum rating value of the recommended operating conditions must be set to 100 Âµs or

less. If the rising time exceeds 100 Âµs, connect a capacitor between the RESET pin and VSS at the

shortest distance, and input âLâ level to RESET pin until the value of supply voltage reaches the

minimum rating value of the recommended operating conditions.

Refer to section â3.1 Electrical characteristicsâ for the reset voltage of the recommended operating

conditions.

Rev.2.00 Aug, 06 2004

REJ09B0107-0200Z

2-74

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