BU9880GUL-W_10 Datasheet, PDF (14/17 Pages) Rohm – WL-CSP EEPROM family I2C BUS

BU9880GUL-W
●I²C BUS input / output circuit
○Input (A0, A1, A2, SCL, SDA)
Technical Note
○Input/Output (SDA)
Fig.47 Input pin circuit diagram
Fig.48 Input /output pin circuit diagram
●Notes on power ON
At power on, in IC internal circuit and set, Vcc rises through unstable low voltage area, and IC inside is not completely reset,
and malfunction may occur. To prevent this, functions of POR circuit and LVCC circuit are equipped. To assure the action,
observe the following condition at power on.
1. Set SDA = 'H' and SCL ='L' or 'H'
2. Start power source so as to satisfy the recommended conditions of tR, tOFF, and Vbot for operating POR circuit.
tR
VCC
Recommended conditions of t_R, t_OFF, Vbot
tOFF
Vbot
0
Fig.49 Rise waveform diagram
t_R
10ms or below
100ms or below
t_OFF
10ms or higher
10ms or higher
Vbot
0.3V or below
0.2V or below
3. Set SDA and SCL so as not to become 'Hi-Z'.
When the above conditions 1 and 2 cannot be observed, take the following countermeasures.
a) In the case when the above conditions 1 cannot be observed. When SDA becomes 'L' at power on .
→Control SCL and SDA as shown below, to make SCL and SDA, 'H' and 'H'.
VCC
SCL
tLOW
SDA
After Vcc becomes stable
tDH tSU:DAT
Fig.50 When SCL='H' and SDA='L'
After Vcc becomes stable
tSU:DAT
Fig.51 When SCL='H' and SDA='L'
b) In the case when the above condition 2 cannot be observed.
→After power source becomes stable, execute software reset(P26).
c) In the case when the above conditions 1 and 2 cannot be observed.
→Carry out a), and then carry out b).
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14/16
2010.11 - Rev.A