Document Number: 002-04578 Rev. *A
Page 46 of 64
MB90910 Series
11.4.3 Power-on Reset
Note : If you change the power supply voltage too rapidly, a power-on reset may occur. We recommend that you start up smoothly
by restraining voltages when changing the power supply voltage during operation, as shown in the figure below. Perform while
not using the PLL clock. However, if voltage drops are within
1 V/s, you can operate while using the PLL clock.
11.4.4 UART
ESCR : SCES = 0, ECCR : SCDE = 0
*: The tcp indicates machine clock
Parameter
Symbol
Pin
name
Condition
Value
Unit
Remarks
Min
Max
Power on rise time
t
R
V
CC
0.05
30
ms
Power off time
t
OFF
V
CC
1
ms
Due to repetitive operation
Parameter
Symbol
Condition
Value
Unit
Min
Max
Serial clock cycle time
t
SCYC
Internal shift clock
operation
C
L
= 80pF + 1TTL.
5 tcp*
ns
SCK
SOT delay time
t
SLOVI
50
50
ns
SIN
SCK
setup time
t
IVSHI
tcp
80
ns
SCK
SIN hold time
t
SHIXI
0
ns
Serial clock “L” pulse width
t
SLSH
External shift clock
operation
C
L
= 80pF + 1TTL.
3 tcp
t
R
ns
Serial clock “H” pulse width
t
SHSL
tcp
10
ns
SCK
SOT delay time
t
SLOVE
2 tcp
60
ns
SIN
SCK
setup time
t
IVSHE
30
ns
SCK
SIN hold time
t
SHIXE
tcp
30
ns
SCK fall time
t
F
10
ns
SCK rise time
t
R
10
ns
V
CC
t
R
t
OFF
2.7 V
0.2 V
0.2 V
0.2 V
V
CC
V
SS
3
V
Hold
s
RAM data
We recommend a ri
s
e of
50 mV/m
s
maxim
u
m.
