BU99901GUZ-W_12 Datasheet, PDF (17/26 Pages) Rohm – Serial EEPROM Series Standard EEPROM WLCSP EEPROM

BU99901GUZ-W (32Kbit)
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 39(a), Figure 39(b), Figure 39(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.
SCL
SDA
SCL
SDA
Dummy clock×14
Start×2
12
13 14
Normal command
Normal command
Figure 39-(a). The case of 14 Dummy clock + START + START+ command input
Start
Dummy clock×9
Start
12
89
Normal command
Normal command
Figure 39-(b). The case of START+9 Dummy clock + START + command input
SCL
SDA
Start×9
1 23
7 89
Figure 39-(c). START × 9 + command input
Normal command
Normal command
* 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, エラー! 編集中のフィールド コードからは、オブジェクトを作成できません。= 0, when to
carry out current read cycle after write, slave address エラー! 編集中のフィールド コードからは、オブジェクトを作成で
きません。= 1 is sent, and if ACK signal sends back 'L', then execute word address input and data so forth.
First write command
S
T
A
Write command
S
T
R
O
T
P
During internal write,
ACK = HIGH is sent back.
S
T
A
Slave
address
R
T
A
C
S
T _Slave
K
A
H
R address
t_{WR T}
A
C
K
H
…
Second write command
…
S
T Slave
A
R
address
T
A
C
K
H
t_WR
S
T Slave
A
R ^address
T
A
C
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 40. Case to continuously write by acknowledge polling
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TSZ22111・15・001
17/23
TSZ02201-0R2R0G100280-1-2
4.SEP.2012 Rev.001