tmp1940cyaf TOSHIBA Semiconductor CORPORATION, tmp1940cyaf Datasheet - Page 437

• Manufacturer Part Number: tmp1940cyaf
• Description: 32-bit Tx System Risc Tx19 Family
• Manufacturer: TOSHIBA Semiconductor CORPORATION

regardless of
operation completes.
DQ7 (Data Polling)
The Data Polling bit, DQ7, indicates to the host system the status of the embedded operation.
Data Polling is valid after the rising edge of the final
When the embedded Program algorithm is in progress, an attempt to read the flash memory will
produce the complement of the data last written to DQ7. Upon completion of the embedded
Program algorithm, an attempt to read the flash memory will produce the true data last written
to DQ7. Therefore, the system can use DQ7 to determine whether the embedded Program
algorithm is in progress or completed.
When the embedded Erase algorithm is in progress, an attempt to read the flash memory will
produce a 0 at the DQ7 output. Upon completion of the embedded Erase algorithm, the flash
memory will produce a 1 at the DQ7 output.
If there is a failure during an embedded operation, DQ7 continues to output the same value.
Thus, DQ7 must always be polled in conjunction with the Exceeded Timing Limits (DQ5) flag.
Figure 3.30 shows the DQ7 polling algorithm.
The flash memory disables address latching when an embedded operation is complete. Data
polling must be performed with a valid programmed address or an address within any of the
non-protected blocks selected for erasure. DQ7 may change asynchronously while
asserted low.
DQ5 (Exceeded Timing Limits)
DQ5 produces a 0 while the program or erase operation is in progress normally. DQ5 produces
a 1 to indicate that the program or erase time has exceeded the specified internal limit. This is a
failure condition that indicates the program or erase cycle was not successfully completed.
The DQ5 failure condition also appears if the system tries to program a 1 to a location that was
previously programmed to a 0. Only an erase operation can change a 0 back to a 1. In this case,
the embedded Program algorithm halts the operation. Once the operation has exceeded the
timing limits, DQ5 will indicate a 1. Note that this is not a device failure condition since the
flash memory was used incorrectly.
Under both these conditions, the flash memory remains locked in Embedded Operation mode.
The system must issue the Read/Reset command to return the flash memory to Read mode.
DQ3 (Block Erase Timer)
The block erase time-out window begins from the rising edge of the
cycle of the command sequence. The erase operation will begin after the time-out has expired.
When the time-out is complete and the erase operation has begun, DQ3 switches from 0 to 1. If
DQ3 is 0, the flash memory will accept additional Auto Block Erase commands. Each time an
Auto Block Erase command is written, the time-out window is reset. To ensure that the
command has been accepted, the system should check DQ3 prior to and following each Auto
Block Erase command. If DQ3 is 1 on the second status check, the command might not have
been accepted.
RDY_BSY (Ready/Busy)
In Programmer mode, the ALE pin functions as the RDY_BSY pin. The programming
equipment can monitor the state of this pin to determine whether an embedded algorithm is in
progress or complete. RDY_BSY produces a 0 when the flash memory is actively erasing or
programming. RDY_BSY produces a 1 when an embedded operation has completed and the
CE
and
WE
. The flash memory automatically returns to Read mode when an embedded
TMP1940FDBF-79
WE
pulse in the command sequence.
TMP1940FDBF
WE
pulse in the sixth bus
OE
is