m45pe40 STMicroelectronics, m45pe40 Datasheet - Page 22

• Manufacturer Part Number: m45pe40
• Description: 4 Mbit, Low Voltage, Page-erasable Serial Flash Memory With Byte-alterability And A 50 Mhz Spi Bus Interface
• Manufacturer: STMicroelectronics

Instructions
6.6
22/46
Read Data Bytes at Higher Speed (FAST_READ)
The device is first selected by driving Chip Select (S) Low. The instruction code for the Read
Data Bytes at Higher Speed (FAST_READ) instruction is followed by a 3-byte address (A23-
A0) and a dummy byte, each bit being latched-in during the rising edge of Serial Clock (C).
Then the memory contents, at that address, is shifted out on Serial Data Output (Q), each
bit being shifted out, at a maximum frequency f
The instruction sequence is shown in
The first byte addressed can be at any location. The address is automatically incremented
to the next higher address after each byte of data is shifted out. The whole memory can,
therefore, be read with a single Read Data Bytes at Higher Speed (FAST_READ)
instruction. When the highest address is reached, the address counter rolls over to
000000h, allowing the read sequence to be continued indefinitely.
The Read Data Bytes at Higher Speed (FAST_READ) instruction is terminated by driving
Chip Select (S) High. Chip Select (S) can be driven High at any time during data output. Any
Read Data Bytes at Higher Speed (FAST_READ) instruction, while an Erase, Program or
Write cycle is in progress, is rejected without having any effects on the cycle that is in
progress.
Figure 11. Read Data Bytes at Higher Speed (FAST_READ) instruction sequence
1. Address bits A23 to A19 are Don’t Care.
S
C
D
Q
S
C
D
Q
7
32 33 34
and data-out sequence
0
6
1
High Impedance
Dummy Byte
5
2
4
35
Instruction
3
3
36 37 38 39 40 41 42 43 44 45 46
4
2
5
1
6
0
MSB
7
7
23
Figure
8
6
22 21
9 10
24 BIT ADDRESS
DATA OUT 1
5
4
11.
C
3
, during the falling edge of Serial Clock (C).
3
28 29 30 31
2
2
1
1
0
47
0
MSB
7
6
DATA OUT 2
5
4
3
2
1
0
MSB
M45PE40
7
AI04006