CAT25020 Datasheet, PDF (4/18 Pages) Catalyst Semiconductor – 1K/2K/4K SPI Serial CMOS EEPROM

CAT25010, CAT25020, CAT25040
FUNCTIONAL DESCRIPTION
The CAT25010/20/40 supports the SPI bus data
transmission protocol. The synchronous Serial Peripheral
Interface (SPI) helps the CAT25010/20/40 to interface
directly with many of today’s popular microcontrollers.
The CAT25010/20/40 contains an 8-bit instruction
register. (The instruction set and the operation codes
are detailed in the instruction set table)
After the device is selected with CS going low, the first
byte will be received. The part is accessed via the SI pin,
with data being clocked in on the rising edge of SCK.
The first byte contains one of the six op-codes that define
the operation to be performed.
PIN DESCRIPTION
SI: Serial Input
SI is the serial data input pin. This pin is used to input all
opcodes, byte addresses, and data to be written to the
CAT25010/20/40. Input data is latched on the rising
edge of the serial clock for SPI modes (0, 0 & 1, 1).
SO: Serial Output
SO is the serial data output pin. This pin is used to
transfer data out of the CAT25010/20/40. During a read
cycle, data is shifted out on the falling edge of the serial
clock for SPI modes (0,0 & 1,1).
Figure 1. Sychronous Data Timing
V_IH
CS
SCK
V_IL
t_CSS
V_IH
V_IL
V_IH
SI
VIL
t_WH
t_SU
t_H
VALID IN
V_OH
HI-Z
SO
V_OL
Note: Dashed Line= mode (1, 1) – – – – –
INSTRUCTION SET
Instruction
Opcode
WREN
0000 0110
WRDI
0000 0100
RDSR
0000 0101
WRSR
READ
WRITE
0000 0001
0000 X011⁽¹⁾
0000 X010⁽¹⁾
Note:
(1) X=0 for CAT25010, CAT25020. X=A8 for CAT25040
t_CS
t_CSH
t_WL
t_RI
tFI
t_V
t_HO
t_DIS
HI-Z
Operation
Enable Write Operations
Disable Write Operations
Read Status Register
Write Status Register
Read Data from Memory
Write Data to Memory
Doc. No. 1006, Rev. S
4
© 2006 by Catalyst Semiconductor, Inc.
Characteristics subject to change without notice