M93S46 ST Microelectronics, M93S46 Datasheet - Page 2

• Manufacturer Part Number: M93S46
• Description: 4Kbit / 2Kbit and 1Kbit 16-bit wide MICROWIRE Serial Access EEPROM with Block Protection
• Manufacturer: ST Microelectronics

M93S66, M93S56, M93S46
SUMMARY DESCRIPTION
This specification covers a range of 4K, 2K, 1K bit
serial Electrically Erasable Programmable Memo-
ry (EEPROM) products (respectively for M93S66,
M93S56, M93S46). In this text, these products are
collectively referred to as M93Sx6.
Figure 2. Logic Diagram
Table 1. Signal Names
The M93Sx6 is accessed through a serial input (D)
and output (Q) using the MICROWIRE bus proto-
col. The memory is divided into 256, 128, 64 x16
bit words (respectively for M93S66, M93S56,
M93S46).
The M93Sx6 is accessed by a set of instructions
which includes Read, Write, Page Write, Write All
2/32
S
D
Q
C
PRE
W
V
V
CC
SS
PRE
W
D
C
S
V CC
V SS
Chip Select Input
Serial Data Input
Serial Data Output
Serial Clock
Protection Register Enable
Write Enable
Supply Voltage
Ground
M93Sx6
Q
AI02020
and instructions used to set the memory protec-
tion. These are summarized in Table 2 and 3).
A Read Data from Memory (READ) instruction
loads the address of the first word to be read into
an internal address pointer. The data contained at
this address is then clocked out serially. The ad-
dress pointer is automatically incremented after
the data is output and, if the Chip Select Input (S)
is held High, the M93Sx6 can output a sequential
stream of data words. In this way, the memory can
be read as a data stream from 16 to 4096 bits (for
the M93S66), or continuously as the address
counter automatically rolls over to 00h when the
highest address is reached.
Within the time required by a programming cycle
(t
Page Write instruction. the whole memory may
also be erased, or set to a predetermined pattern,
by using the Write All instruction.
Within the memory, a user defined area may be
protected against further Write instructions. The
size of this area is defined by the content of a Pro-
tection Register, located outside of the memory
array. As a final protection step, data may be per-
manently protected by programming a One Time
Programming bit (OTP bit) which locks the Protec-
tion Register content.
Programming is internally self-timed (the external
clock signal on Serial Clock (C) may be stopped or
left running after the start of a Write cycle) and
does not require an erase cycle prior to the Write
instruction. The Write instruction writes 16 bits at a
time into one of the word locations of the M93Sx6,
the Page Write instruction writes up to 4 words of
16 bits to sequential locations, assuming in both
cases that all addresses are outside the Write Pro-
tected area. After the start of the programming cy-
cle, a Busy/Ready signal is available on Serial
Data Output (Q) when Chip Select Input (S) is
driven High.
Figure 3. DIP, SO and TSSOP Connections
Note: 1. See page 26 (onwards) for package dimensions, and how
W
), up to 4 words may be written with help of the
to identify pin-1.
Q
C
D
S
1
2
3
4
M93Sx6
AI02021
8
7
6
5
V CC
PRE
W
V SS