Rainbow Electronics BR24L02FVM-W - Manual (Page 17)

BR24L02-W / BR24L02F-W / BR24L02FJ-W /
Memory ICs BR24L02FV-W / BR24L02FVM-W
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5) Notes for power supply
V
CC rises through the low voltage region in which internal circuit of IC and the controller are unstable, so that device
may not work properly due to an incomplete reset of internal circuit.
To prevent this, the device has the feature of P.O.R. and LV
CC .
In the case of power up, keep the following conditions to ensure functions of P.O.R and LV CC .
(1) It is necessary to be “SDA=H” and “SCL=’L’ or ‘H’ ”.
(2) Follow the recommended conditions of t
R , t OFF , Vbot for the function of P.O.R. durning power up.
t R
t OFF
Vbot
V CC rising wave from
V CC
0
Recommended conditions of t R , t OFF , Vbot
Below 10ms
t R t OFF Vbot
Below 100ms
Below 0.3V
Below 0.2V
Above 10ms
Above 10ms
(3) Prevent SDA and SCL from being “Hi-Z”.
In case that condition 1. and / or 2. cannot be met, take following actions.
A) Unable to keep condition 1. (SDA is “LOW” during power up.)
→
Control SDA, SCL to be “HIGH” as figure below.
t LOW
t DH t SU:DAT
After V CC becomes stable
SDA
SCL
V CC
a) SCL = "H" and SDA = "L"
t SU:DAT
After V CC becomes stable
b) SCL = "L" and SDA = "L"
B) Unable to keep condition 2.
→
After power becomes stable, execute software reset. (See page14 )
C) Unable to keep condition 1 and 2.
→
Follow the instruction A first, then the instruction B.