4501_M Datasheet, PDF (157/212 Pages) Renesas Technology Corp – 4-BIT CISC SINGLE-CHIP MICROCOMPUTER 4500 SERIES

4501 Group
APPLICATION
2.5 Reset
2.5.3 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.
• Register Z (2 bits)
• Register D (3 bits)
• 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 2.0 V must be set to 100 µs or less. If the rising time exceeds 100 µs, connect a capacitor
between the RESET pin and VSS at the shortest distance, and input “L” level to RESET pin until the
value of supply voltage reaches the minimum operating voltage.
Rev.2.01 Feb 07, 2005
REJ09B0192-0201
2-40