83
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER with CLOSED CAPTION DECODER
and ON-SCREEN DISPLAY CONTROLLER
M37274MA-XXXSP
PRELIMINARY
Notice:
This
is not
a final
specification.
Some
paramentic
limits
are
subject
to change.
MITSUBISHI MICROCOMPUTERS
RESET CIRCUIT
When the oscillation of a quartz-crystal oscillator or a ceramic reso-
nator is stable and the power source voltage is 5 V
± 10 %, hold the
______
RESET pin at LOW for 2
s or more, then return is to HIGH. Then, as
shown in Figure 94, reset is released and the program starts form
the address formed by using the content of address FFFF16 as the
high-order address and the content of the address FFFE16 as the
low-order address. The internal state of microcomputer at reset are
shown in Figures 5 to 9.
An example of the reset circuit is shown in Figure 93.
The reset input voltage must be kept 0.9 V or less until the power
source voltage surpasses 4.5 V.
Fig. 94. Reset Sequence
Fig. 93. Example of Reset Circuit
Power source voltage 0 V
Reset input voltage 0 V
4.5 V
0.9 V
Poweron
26
30
27
Vcc
RESET
Vss
M37274MA-XXXSP
1
5
4
3
0.1
F
M51953AL
XIN
φ
RESET
Internal RESET
SYNC
Address
Data
32768 count of XIN
clock cycle (Note 3)
Reset address from the vector table
?
01, S
01, S-1 01, S-2
FFFE
FFFF
ADH,
ADL
?
ADL
ADH
Notes 1 : f(XIN) and f(
) are in the relation : f(XIN) = 2f (
φ).
2: A question mark (?) indicates an undefined state that
depends on the previous state.
3 : Immediately after a reset, timer 3 and timer 4 are
connected by hardware. At this time, “FF 16” is set
in timer 3 and “0716” is set to timer 4. Timer 3 counts down
with f(XIN
)/16, and reset state is released by the timer 4
overflow signal.