M93S46 ST Microelectronics, M93S46 Datasheet - Page 3

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

An internal Power-on Data Protection mechanism
in the M93Sx6 inhibits the device when the supply
is too low.
POWER-ON DATA PROTECTION
To prevent data corruption and inadvertent write
operations during power-up, a Power-On Reset
(POR) circuit resets all internal programming cir-
cuitry, and sets the device in the Write Disable
mode.
– At Power-up and Power-down, the device must
– When V
For the M93Sx6 devices (5V range) the POR
threshold voltage is around 3V. For the M93Sx6-
W (3V range) and M93Sx6-R (2V range) the POR
threshold voltage is around 1.5V.
not be selected (that is, Chip Select Input (S)
must be driven Low) until the supply voltage
reaches the operating value V
Table 5 to Table 6.
properly reset (in the Write Disable mode) and
is ready to decode and execute incoming in-
structions.
CC
reaches its valid level, the device is
CC
specified in
INSTRUCTIONS
The instruction set of the M93Sx6 devices con-
tains seven instructions, as summarized in Table 2
to Table 3. Each instruction consists of the follow-
ing parts, as shown in Figure 4:
The M93Sx6 devices are fabricated in CMOS
technology and are therefore able to run as slow
as 0 Hz (static input signals) or as fast as the max-
imum ratings specified in Table 16 to Table 19.
Each instruction is preceded by a rising edge on
Chip Select Input (S) with Serial Clock (C) being
held Low.
A start bit, which is the first ‘1’ read on Serial
Data Input (D) during the rising edge of Serial
Clock (C).
Two op-code bits, read on Serial Data Input (D)
during the rising edge of Serial Clock (C).
(Some instructions also use the first two bits of
the address to define the op-code).
The address bits of the byte or word that is to be
accessed. For the M93S46, the address is
made up of 6 bits (see Table 2). For the M93S56
and M93S66, the address is made up of 8 bits
(see Table 3).
M93S66, M93S56, M93S46
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