M93S66-125 M93S56-125 M93S46-125

Power-on data protection

Doc ID 022567 Rev 1

7/28

2

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 circuitry, and sets the device in the Write

Disable mode.

●

At Power-up and Power-down, the device must not be selected (that is, Chip Select

specified in Section 8: DC and AC parameters.

●

mode) and is ready to decode and execute incoming instructions.

For the M93Sx6-125, the POR threshold voltage is around 1.5 V.

3

Instructions

The instruction set of the M93Sx6-125 devices contains seven instructions, as summarized

in Table 2 and Table 3. Each instruction consists of the following:

●

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 opcode 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 opcode).

●

The address bits of the byte or word that is to be accessed. For the M93S46-125, the

address is made up of 6 bits (see Table 2). For the M93S56-125 and M93S66-125, the

address is made up of 8 bits (see Table 3).

The M93Sx6-125 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 maximum ratings specified in Table 9.