M45PE40-VMP6 STMICROELECTRONICS [STMicroelectronics], M45PE40-VMP6 Datasheet - Page 13

• Manufacturer Part Number: M45PE40-VMP6
• Description: 4 Mbit, Low Voltage, Page-Erasable Serial Flash Memory With Byte-Alterability and a 33 MHz SPI Bus Interface
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

Read Identification (RDID)
The Read Identification (RDID) instruction allows
the 8-bit manufacturer identification to be read, fol-
lowed by two bytes of device identification. The
manufacturer identification is assigned by JEDEC,
and has the value 20h for STMicroelectronics. The
device identification is assigned by the device
manufacturer, and indicates the memory type in
the first byte (40h), and the memory capacity of the
device in the second byte (13h).
Any Read Identification (RDID) instruction while
an Erase or Program cycle is in progress, is not
decoded, and has no effect on the cycle that is in
progress.
Table 5. Read Identification (RDID) Data-Out Sequence
Figure 9. Read Identification (RDID) Instruction Sequence and Data-Out Sequence
Manufacturer Identification
S
C
D
Q
20h
0
High Impedance
1
2
Instruction
3
4
5
6
7
MSB
Manufacturer Identification
8
9 10 11 12 13 14 15
Memory Type
40h
The device is first selected by driving Chip Select
(S) Low. Then, the 8-bit instruction code for the in-
struction is shifted in. This is followed by the 24-bit
device identification, stored in the memory, being
shifted out on Serial Data Output (Q), each bit be-
ing shifted out during the falling edge of Serial
Clock (C).
The instruction sequence is shown in
The Read Identification (RDID) instruction is termi-
nated by driving Chip Select (S) High at any time
during data output.
When Chip Select (S) is driven High, the device is
put in the Standby Power mode. Once in the
Standby Power mode, the device waits to be se-
lected, so that it can receive, decode and execute
instructions.
Device Identification
MSB
15 14 13
16 17 18
Device Identification
3
28 29 30 31
2
Memory Capacity
1
0
13h
AI06809b
Figure
M45PE40
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