BU9891GUL-W Rohm, BU9891GUL-W Datasheet - Page 12

• Manufacturer Part Number: BU9891GUL-W
• Description: WL-CSP EEPROM family Microwire Bus
• Manufacturer: Rohm

© 2010 ROHM Co., Ltd. All rights reserved.
BU9891GUL-W
www.rohm.com
5) READY / BUSY status display (DO terminal)
*Do not input any command while status signal is output. Command input in BUSY area is cancelled, but command input in READY area is accepted.
Therefore, status READY output is cancelled, and malfunction and mistake write may be made.
○Pull up resistance Rpu and pull down resistance Rpd of DO pin
This display outputs the internal status signal. When CS is started after tCS (Min.200ns)
from CS fall after write command input, “H” or “L” is output.
R/B display＝“L” (BUSY) = write under execution
accepted.
R/B display = “H” (READY) = command wait status
in the area
(DO status)
(DO status)
As for pull up and pull down resistance value, select an appropriate value to this resistance value from microcontroller
VIH, VIL, and VOH, IOH, VOL, IOL characteristics of this IC.
Microcontroller
Microcontroller
Fig.47 DO pull down resistance
“L” input
Fig.46 DO pull up resistance
“H” input
VILM
VIHM
After the timer circuit in the IC works and creates the period of tE/W, this time circuit completes automatically.
And write to the memory cell is made in the period of tE/W, and during this period, other command is not
Even after tE/W (max.5ms) from write of the memory cell, the following command is accepted.
Therefore, CS=“H” in the period of tE/W, and when input is in SK, DI, malfunction may occur, therefore, DI=“L”
CS=“H”. (Especially, in the case of shared input port, attention is required.)
CS
SK
DI
DO
Rpu
Rpd
High-Z
WRITE
INSTRUCTION
IOLE
IOHE
CLOCK
VOLE
VOHE
“H” output
“L” output
EEPROM
EEPROM
Fig.48 R/B status output timing chart
t
SV
BUSY
STATUS
12/17
Example) When V
With the value of Rpu to satisfy the above equation, VOLE becomes 0.4V
or below, and with VILM(=0.8V), the equation ④ is also satisfied.
With the value of Rpd to satisfy the above equation, VOHE becomes 2.4V
or below, and with VIHM (=3.5V), the equation ⑥ is also satisfied.
READY
Example) When V
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∴
∴
・VOLE
・IOLE
・VILM
・VOHE
・IOHE
・VIHM
from the equation ③,
VOHE ≧ VIHM
VIHM=Vcc×0.7V from the equation ⑤,
VOLE ≦ VILM
Rpu ≧
Rpu ≧
Rpu ≧ 2.2 [kΩ]
Rpd ≧
Rpd ≧
Rpd ≧ 48 [kΩ]
CC
=5V, VOLE=0.4V, IOLE=2.1mA, VILM=0.8V,
: EEPROM VOL specifications
: EEPROM IOL specifications
: Microcontroller VIL specifications
: EEPROM VOH specifications
: EEPROM IOH specifications
: Microcontroller VIH specifications
CC
Vcc－VOLE
=5V, VOHE=Vcc－0.2V, IOHE=0.1mA,
2.1×10
0.1×10
VOHE
IOHE
IOLE
5－0.4
5－0.2
-3
-3
・・・③
・・・④
・・・⑤
・・・⑥
Technical Note
2010.07 - Rev.A
Datasheet pdf - http://www.DataSheet4U.net/