Datasheet
DocID4997 Rev 15 11/33
M93C86-x M93C76-R M93C66-x M93C56-x M93C46-x Instructions
32
5 Instructions
The instruction set of the M93Cx6 devices contains seven instructions, as summarized in
Table 4 to Table 6. Each instruction consists of the following parts, as shown in Figure 5:
READ, WRITE, WEN, WDS sequences:
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 4). 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 5). 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 6).
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 “AC
characteristics” tables, in
Section 10: DC and AC parameters.
Table 4. 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.