Instructions
M93C86, M93C76, M93C66, M93C56, M93C46
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
x8 origination (ORG = 0)
x16 origination (ORG = 1)
Start Op-
Required
clock
Required
Address
Instruction
Description
Address
bit
code
Data
Data
clock
(1)
(1)
cycles
cycles
Read Data from
Memory
READ
WRITE
WEN
1
1
1
1
1
1
1
10
01
00
00
11
00
00
A6-A0
A6-A0
Q7-Q0
D7-D0
A5-A0
A5-A0
Q15-Q0
D15-D0
Write Data to
Memory
18
10
10
10
10
18
25
9
11X
XXXX
Write Enable
Write Disable
11 XXXX
00 XXXX
A5-A0
00X
XXXX
WDS
9
Erase Byte or
Word
ERASE
ERAL
WRAL
A6-A0
9
10X
XXXX
Erase All Memory
10 XXXX
9
Write All Memory
with same Data
01X
XXXX
D7-D0
01 XXXX D15-D0
25
1. X = Don't Care bit.
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STMICROELECTRONICS [ ST ]
