A93C66
AiT Semiconductor Inc.
www.ait-ic.com
THREE-WIRE SERIAL EEPROM
4K (512 X 8 OR 256 X 16)
DETAILED INFORMATION
The A93C66 is accessed via a simple and versatile three-wire serial communication interface. Device
operation is controlled by seven instructions issued by the host processor. A valid instruction starts with a
rising edge of CS and consists of a start bit (logic“1”) followed by the appropriate OP Code and the desired
memory address location.
Instruction Set of A93C66
Address
Data
OP
Instruction
SB
Comments
Code
x8
x16
x8
x16
Reads data stored in memory,
at specified address
Write enable must precede all
programming modes
READ
EWEN
1
1
10
00
A8 - A0
A7 - A0
11XXXXXXX 11XXXXXX
Erase memory location An - A0
ERASE
WRITE
1
1
11
01
A8 - A0
A8 - A0
A7 - A0
A7 - A0
Writes memory location An - A0
D7 - D0 D15 - D0
Erases all memory locations.
Valid only at VCC = 4.5V to 5.5V
Writes all memory locations.
Valid only at VCC = 4.5V to 5.5V
Disables all programming
instructions
ERAL
WRAL
EWDS
1
1
1
00
00
00
10XXXXXXX 10XXXXXX
01XXXXXXX 01XXXXXX D7 - D0 D15 - D0
00XXXXXXX 00XXXXXX
The X’s in the address field represent don’t care values and must be clocked.
READ (READ)
The Read (READ) instruction contains the address code for the memory location to be read. After the
instruction and address are decoded, data from the selected memory location is available at the serial output
pin DO. Output data changes are synchronized with the rising edges of serial clock SK. It should be noted that
a dummy bit (logic “0”) precedes the 8- or 16-bit data output string. The A93C66 supports sequential read
operations. The device will automatically increment the internal address pointer and clock out the next
memory location as long as Chip Select (CS) is held high .In this case, the dummy bit (logic “0”) will not be
clocked out between memory locations, thus allowing for a continuous steam of data to be read.
ERASE/WRITE (EWEN):
To assure data integrity, the part automatically goes into the Erase/Write Disable (EWDS) state when power
is first applied. An Erase/Write Enable (EWEN) instruction must be executed first before any programming
instructions can be carried out. Please note that once in the EWEN state, programming remains enabled until
an EWDS instruction is executed or VCC power is removed from the part.
REV1.0
- MAY 2012 RELEASED -
- 7 -
AITSEMI [ AiT Semiconductor ]
