BU9880GUL-W_12 Datasheet, PDF (16/26 Pages) Rohm – WLCSP EEPROM

BU9880GUL-W (64Kbit)
Datasheet
●Software reset
Software reset is executed when to avoid malfunction after power on, and to reset during command input. Software reset
has several kinds, and 3 kids of them are shown in the figure below. (Refer to Figure 37(a), Figure 37(b), Figure 37(c).) In
dummy clock input area, release the SDA bus ('H' by pull up). In dummy clock area, ACK output and read data '0' (both 'L'
level) may be output from EEPROM, therefore, if 'H' is input forcibly, output may conflict and over current may flow, leading
to instantaneous power failure of system power source or influence upon devices.
Dummy clock×14
Start×2
SCL
SDA
SCL
SDA
12
13 14
Normal command
Normal command
Figure 37-(a) The case of 14 Dummy clock + START + START+ command input
Start
Dummy clock×9
Start
12
89
Normal command
Normal command
Figure 37-(b) The case of START+9 Dummy clock + START + command input
SCL
SDA
Start×9
1 23
7 89
Normal command
Normal command
Figure 37-(c) START × 9 + command input * Start command from START input.
●Acknowledge polling
During internal write, all input commands are ignored, therefore ACK is not sent back. During internal automatic write
execution after write cycle input, next command (slave address) is sent, and if the first ACK signal sends back 'L', then it
means end of write action, while if it sends back 'H', it means now in writing. By use of acknowledge polling, next command
can be executed without waiting for tWR = 5ms.
When to write continuously, R / W = 0, when to carry out current read cycle after write, slave address R / W = 1 is sent,
and if ACK signal sends back 'L', then execute word address input and data so forth.
First write command
S
T
S
A Write command ^T
R
O
T
P
During internal write,
ACK = HIGH is sent back.
S
T
A
R
T
Slave
address
A
C
K
S
T
A
H
R
t_WR ^T
Slave
A
C
address ^K
H
…
Second write command
…
S
T
A
R
T
Slave ^A
C
address K
H
t_WR
S
T
A
R
T
Slave
A
C
address ^K
L
Word
address
A
C
K
L
Data
AS
CT
KO
LP
After completion of internal
write, ACK=LOW is sent back,
so input next word address and
data in succession.
Figure 38. Case to continuously write by acknowledge polling
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TSZ22111・15・001
16/22
TSZ02201-0R2R0G100340-1-2
21.AUG.2012 Rev.001