R1EX24256BSAS0A_12 Datasheet, PDF (6/18 Pages) Renesas Technology Corp – Two-wire serial interface 256k EEPROM (32-kword 8-bit)

R1EX24256BSAS0A/R1EX24256BTAS0A
Pin Function
Serial Clock (SCL)
The SCL pin is used to control serial input/output data timing. The SCL input is used to positive edge clock data into
EEPROM device and negative edge clock data out of each device. Maximum clock rate is 400 kHz.
Serial Input/Output Data (SDA)
The SDA pin is bidirectional for serial data transfer. The SDA pin needs to be pulled up by resistor as that pin is open-
drain driven structure. Use proper resistor value for your system by considering V_OL, I_OL and the SDA pin capacitance.
Except for a start condition and a stop condition which will be discussed later, the SDA transition needs to be completed
during the SCL low period.
Data Validity (SDA data change timing waveform)
SCL
SDA
Data
change
Data
change
Note: High-to-low and low-to-high change of SDA should be done during the SCL low period.
Device Address (A0, A1, A2)
Eight devices can be wired for one common data bus line as maximum. Device address pins are used to distinguish
each device and device address pins should be connected to V_CC or V_SS. When device address code provided from SDA
pin matches corresponding hard-wired device address pins A0 to A2, that one device can be activated.
Pin Connections for A0 to A2
Memory size Max connect number
A2
256k bit
8
V_CC/V_SS *¹
Note: 1. During floating, "V_CC/V_SS" are fixed to V_SS.
Pin connection
A1
V_CC/V_SS *¹
A0
V_CC/V_SS *¹
Note
Write Protect (WP)
When the Write Protect pin (WP) is high, the write protection feature is enabled and operates as shown in the following
table. Also, acknowledgment "0" is outputted after inputting device address and memory address. After inputting write
data, acknowledgment "1"(NO ACK) is outputted.
When the WP is low, write operation for all memory arrays are allowed. The read operation is always activated
irrespective of the WP pin status.
Write Protect Area
WP pin status
V_IH
V_IL
Write protect area
256k bit
Full (256k bit)
Normal read/write operation
R10DS0005EJ0101 Rev.1.01
Jul. 26, 2012
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