HMS87C5216 Datasheet, PDF (67/76 Pages) List of Unclassifed Manufacturers – CMOS SINGLE-CHIP 8-BIT MICROCONTROLLER FOR UR(Universal Remocon) & WIRELESS KEYBOARD

VDD
PRESCALER COUNT START
HMS87C5216
OSC. START TIMING
Figure 17-3 Oscillator stabilization diagram
RESET
INTERNAL
RESET
ADDR. BUS
SP SP-1
SP-2
FFFE FFFF NEW PC
INTERNAL
DATA BUS
FE LSB MSB
VECTOR VECTOR
Figure 17-4 Reset Timing by Diagram
17.3 Low Voltage Detection Mode
(1) Low voltage detection condition
An on board voltage comparator checks that VDD is at the re-
quired level to ensure correct operation of the device. If VDD is
below a certain level, Low voltage detector forces the device into
low voltage detection mode.
(2) Low Voltage Detection Mode
There is no power consumption except stop current, stop mode
release function is disabled. All I/O port is configured as input
mode and Data memory is retained until voltage through external
capacitor is worn out. In this mode, all port can be selected with
Pull-up resistor by Mask option. If there is no information on the
Mask option sheet ,the default pull up option (all port connect to
pull-up resistor ) is selected.
(3) Release of Low Voltage Detection Mode
Reset signal result from new battery(normally 3V) wakes the low
voltage detection mode and come into normal reset state. It de-
pends on user whether to execute RAM clear routine or not.
SEP. 2004 Ver 1.01