M50FLW040AK1 STMicroelectronics, M50FLW040AK1 Datasheet - Page 18

• Manufacturer Part Number: M50FLW040AK1
• Description: 4 Mbit (5 x 64KByte Blocks + 3 x 16 x 4KByte Sectors) 3V Supply Firmware Hub / Low Pin Count Flash Memory
• Manufacturer: STMicroelectronics

M50FLW040A, M50FLW040B
COMMAND INTERFACE
All Bus Write operations to the device are inter-
preted by the Command Interface. Commands
consist of one or more sequential Bus Write oper-
ations. An internal Program/Erase Controller han-
dles all timings, and verifies the correct execution
of the Program and Erase commands. The Pro-
gram/Erase Controller provides a Status Register
whose output may be read at any time to monitor
the progress or the result of the operation.
The Command Interface reverts to the Read mode
when power is first applied, or when exiting from
Reset. Command sequences must be followed ex-
actly. Any invalid combination of commands will be
ignored. See
Codes.
Table 11. Command Codes
The following commands are the basic commands
used to read from, write to, and configure the de-
vice. The following text descriptions should be
read in conjunction with
Read Memory Array Command. The
Memory Array command returns the device to its
Read mode, where it behaves like a ROM or
EPROM. One Bus Write cycle is required to issue
the Read Memory Array command and return the
device to Read mode. Once the command is is-
sued, the device remains in Read mode until an-
other command is issued. From Read mode, Bus
Read operations access the memory array.
If the Program/Erase Controller is executing a Pro-
gram or Erase operation, the device will not accept
18/52
decimal
Hexa-
B0h
D0h
FFh
10h
20h
32h
40h
50h
70h
80h
90h
Alternative Program Setup, Double/
Quadruple Byte Program Setup, Chip
Erase Confirm
Block Erase Setup
Sector Erase Setup
Program, Double/Quadruple Byte
Program Setup
Clear Status Register
Read Status Register
Chip Erase Setup
Read Electronic Signature
Program/Erase Suspend
Program/Erase Resume, Block Erase
Confirm, Sector Erase Confirm
Read Memory Array
Table 11.
for the available Command
Table
Command
13..
Read
any Read Memory Array commands until the oper-
ation has completed.
For a multibyte read, in the FWH mode, the ad-
dress, that was transmitted with the command, will
be automatically aligned, according to the MSIZE
granularity. For example, if MSIZE=7, regardless
of any values that are provided for A6-A0, the first
output will be from the location for which A6-A0 are
all ‘0’s.
Read Status Register Command. The
Status Register command is used to read the Sta-
tus Register. One Bus Write cycle is required to is-
sue the Read Status Register command. Once the
command is issued, subsequent Bus Read opera-
tions read the Status Register until another com-
mand is issued. See the section on the Status
Register for details on the definitions of the Status
Register bits.
Read Electronic Signature Command. The
Read Electronic Signature command is used to
read the Manufacturer Code and the Device Code.
One Bus Write cycle is required to issue the Read
Electronic Signature command. Once the com-
mand is issued, the Manufacturer Code and De-
vice Code can be read using conventional Bus
Read operations, and the addresses shown in
ble
Table 12. Electronic Signature Codes
Note: 1. A22 should be ‘1’, and the ID lines and upper address bits
The device remains in this mode until another
command is issued. That is, subsequent Bus
Read operations continue to read the Manufactur-
er Code, or the Device Code, and not the Memory
Array.
Program Command. The Program command
can be used to program a value to one address in
the memory array at a time.
The Program command works by changing appro-
priate bits from ‘1’ to ‘0’. (It cannot change a bit
from ‘0’ back to ‘1’. Attempting to do so will not
modify the value of the bit. Only the Erase com-
mand can set bits back to ‘1’. and does so for all of
the bits in the block.)
Two Bus Write operations are required to issue the
Program command. The second Bus Write cycle
latches the address and data, and starts the Pro-
gram/Erase Controller.
Manufacturer Code
Device Code
12..
should be set according to the rules illustrated in
Table 6.
Code
and
M50FLW040A
M50FLW040B
Table
8..
Address
...00000h
...00001h
1
Table
Data
20h
08h
28h
Read
Ta-
5.,