UPSD3422 datasheet(208/293 Pages) STMICROELECTRONICS

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PSD module

uPSD34xx

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the 8032 should test the Toggle Flag Bit (DQ6) again, since the Toggle Flag Bit (DQ6) may

have changed simultaneously with the Error Flag Bit (DQ5) (see Figure 73).

The Error Flag Bit (DQ5) is set if either an internal time-out occurred while the embedded

algorithm attempted to program the byte, or if the 8032 attempted to program bit to logic ’1’

when that bit was already programmed to logic ’0’ (must erase to achieve logic ’1’).

It is suggested (as with all Flash memories) to read the location again after the embedded

programming algorithm has completed, to compare the byte that was written to Flash

memory with the byte that was intended to be written.

When using the Data Toggle method during an erase operation, Figure 73 still applies. the

Toggle Flag Bit (DQ6) toggles until the erase operation is complete. A ’1’ on the Error Flag

Bit (DQ5) indicates a time-out condition on the Erase cycle, a ’0’ indicates no error. The

8032 can read any location within the sector being erased to get the Toggle Flag Bit (DQ6)

and the Error Flag Bit (DQ5).

PSDsoft Express generates ANSI C code functions the user may use to implement these

Data Toggling algorithms.

Figure 73.

Data toggle flowchart

28.5.12

Ready/Busy (PC3)

This signal can be used to output the Ready/Busy status of a program or erase operation on

either Flash memory. The output on the Ready/Busy pin is a ’0’ (Busy) when either Flash

memory array is being written, or when either Flash memory array is being erased. The

output is a ’1’ (Ready) when no program or erase operation is in progress. To activate this

function on this pin, the user must select the “Ready/Busy” selection in PSDsoft Express

when configuring pin PC3. This pin may be polled by the 8032 or used as a 8032 interrupt to

READ

DQ5 & DQ6

START

READ DQ6

FAIL

PASS

AI01370B

DQ6

TOGGLE

YES

DQ5

= 1

YES

DQ6

TOGGLE

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