M39432 Datasheet, PDF (7/28 Pages) STMicroelectronics – Single Chip 4 Mbit Flash Memory and 256 Kbit Parallel EEPROM

M39432
Table 6. Status Bits
EF
EE
DQ7 DQ6 DQ5
Flash
V_IL
V_IH
Data Toggle Error
Polling Flag Flag
EEPROM
V_IH
V_IL
Data Toggle
Polling Flag
X
Note: 1. X = Not a guaranteed value, can be read either as ‘1’ or ‘0’.
DQ4
X
X
DQ3
Erase
Time-
Out
X
DQ2
X
X
DQ1
X
X
DQ0
X
X
Automatic Stand-by
If CMOS levels (V_CC±0.2V) are used to drive the
bus, and the bus is inactive for more than 150 ns,
the memory enters the Automatic Stand-by state.
The internal supply current is reduced to the
Stand-by Supply Current, I_CC3.
Deep Power Down
The I_CC consumption mode can be reduced to a
minimum using the Deep Power Down instruction
(as shown in Table 4). The device is set in a sleep
mode until the next Reset instruction is executed.
EEPROM Power Down
The M39432 can power-down the EEPROM block
using the specific instruction shown in Table 4.
Once in this state, the EEPROM block is no longer
accessible, until a Return instruction is executed.
READ
Read operations and instructions can be used:
– to read the contents of the memory array (Flash
memory block or EEPROM block)
– to read the memory array status and identifiers
(Flash memory block or EEPROM block).
Read Data (from Flash Memory or EEPROM)
For a Read operation, the Output Enable (G) and
one Chip Enable (EF or EE) must be driven low.
Read the Manufacturer Identifier
There are two alternative methods for reading the
Manufacturer Identifier: using a Read operation or
using a Read instruction.
Read Operation. The Manufacturer Identifier can
be read with a Read operation by applying V_ID (as
specified in Table 11) on A9, and the logic levels
specified in Table 5 applied to A0, A1, A6.
Read Instruction. The Manufacturer Identifier can
also be read using an instruction composed of four
operations: three specific Write operations (as
specified in Table 4) and a Read operation. This
either accesses the Manufacturer Identifier, the
Flash Block Identifier or the Flash Sector
Protection Status, depending on the levels that are
being applied to A0, A1, A6, A16, A17 and A18.
Read the Flash Block Identifier
Similarly, there are two alternative methods for
reading the Flash Block Identifier (E3h): using a
Read operation or using a Read instruction.
Please see the previous section, entitled “Read
the Manufacturer Identifier”, and Table 5 and
Table 4 for details.
Read the EEPROM Block Identifier
The EEPROM Block Identifier (64 bytes, user de-
fined) can be read with a single Read operation by
holding A6 low and A9 at V_ID (see Table 5).
Read the OTP Row
The OTP row is mapped in the EEPROM block.
With EE held low, and EF held high, an EEPROM
Read instruction is composed, as specified in
Figure 4. Data Polling Flowchart
START
READ DQ5 & DQ7
at VALID ADDRESS
DQ7
=
YES
DATA
NO
NO _DQ5
=1
YES
READ DQ7
DQ7
=
YES
DATA
NO
FAIL
PASS
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