Instructions

M93C86, M93C76, M93C66, M93C56, M93C46

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5

Instructions

The instruction set of the M93Cx6 devices contains seven instructions, as summarized in

Table 5. to Table 7.. Each instruction consists of the following parts, as shown in Figure 4.:

●

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 M93C46, the

address is made up of 6 bits for the x16 organization or 7 bits for the x8 organization

(see Table 5.). For the M93C56 and M93C66, the address is made up of 8 bits for the

x16 organization or 9 bits for the x8 organization (see Table 6.). For the M93C76 and

M93C86, the address is made up of 10 bits for the x16 organization or 11 bits for the x8

organization (see Table 7.).

The M93Cx6 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 20. to

Table 23..

Table 5.

Instruction set for the M93C46

Instruction

Description

Start

bit

Op-

code

x8 origination (ORG = 0)

x16 origination (ORG = 1)

Address

(1)

Data

Required

clock

cycles

Address

(1)

Data

Required

clock

cycles

READ

Read Data from

Memory

1

10

A6-A0

Q7-Q0

A5-A0

Q15-Q0

WRITE

Write Data to

Memory

1

01

A6-A0

D7-D0

18

A5-A0

D15-D0

25

WEN

Write Enable

1

00

11X

XXXX

10

11 XXXX

9

WDS

Write Disable

1

00

00X

XXXX

10

00 XXXX

9

ERASE

Erase Byte or

Word

1

11

A6-A0

10

A5-A0

9

ERAL

Erase All Memory

1

00

10X

XXXX

10

10 XXXX

9

WRAL

Write All Memory

with same Data

100

01X

XXXX

D7-D0

18

01 XXXX

D15-D0

25

1.

X = Don't Care bit.