M37221 Mitsubishi, M37221 Datasheet - Page 50

• Manufacturer Part Number: M37221
• Description: SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER for VOLTAGE SYNTHESIZER with ON-SCREEN DISPLAY CONTROLLER
• Manufacturer: Mitsubishi

RESET CIRCUIT
The M37221EF-XXXSP is reset according to the sequence shown in
Figure 56. It starts the program from the address formed by using the
content of address FFFF
tent of the address FFFE
RESET pin is held at “L” level for 2 s or more while the power source
voltage is 5 V ± 10 % and the oscillation of a quartz-crystal oscillator
Fig. 56. Reset sequence
50
RESET
X
Internal RESET
SYNC
Address
Data
IN
16
16
as the high-order address and the con-
as the low-order address, when the
clock cycle (Note 3)
32768 count of X
?
IN
?
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER for VOLTAGE SYNTHESIZER
?
?
01, S
?
01, S-1 01, S-2
Notes 1 : f(X
?
M37221EF-XXXSP,M37221EFSP
or a ceramic resonator is stable and then returned to “H” level. The
internal state of microcomputer at reset are shown in Figure 57.
An example of the reset circuit is shown in Figure 55.
The reset input voltage must be kept 0.6 V or less until the power
source voltage surpasses 4.5 V.
Fig. 55. Example of reset circuit
2 : A question mark (?) indicates an undefined state that
3 :
?
Power source voltage 0 V
Immediately after a reset, timer 3 and timer 4 are
connected in hardware. At this time, “FF
overflow signal.
depends on the previous state.
in timer 3 and “07
with f(X
FFFE
Reset input voltage 0 V
IN
AD
) and f( ) are in the relation : f(X
IN
L
FFFF
)/16, and reset state is released by the timer 4
AD
with ON-SCREEN DISPLAY CONTROLLER
H
AD
AD
16
H
L
MITSUBISHI MICROCOMPUTERS
,
” is set to timer 4. Timer 3 counts down
M51953AL
1
3
Reset address from the vector table
5
4
0.1 F
Poweron
IN
) = 2·f ( ).
16
M37221EF-XXXSP
” is set
22
25
21
0.6 V
4.5 V
Vcc
RESET
Vss