Datasheet

744
11011B–ATARM–21-Feb-12
SAM3N
38.3 Flash Memory
38.3.1 Flash: Flash Programming
When writing data into the Flash memory plane (either through the EEFC, using the IAP function
or FFPI), the data may not be correctly written (i.e the data written is not the one expected).
Problem Fix/Workaround
Set the number of Wait States (WS) at 6 (FWS = 6) during the programming.
38.3.2 Flash: Fetching Error after Reading the Unique Identifier
After reading the Unique Identifier (or using the STUI/SPUI command), the processor may fetch
wrong instructions. It depends on the code and on the region of the code.
Problem Fix/Workaround
In order to avoid this problem, follow the steps below:
1) Set bit 16 of EEFC Flash Mode Register to 1
2) Send the Start Read Unique Identifier command (STUI) by writing the Flash Command
Register with the STUI command
3) Wait for the FRDY bit to fall
4) Read the Unique ID (and next bits if required)
5) Send the Stop Read Unique Identifier command (SPUI) by writing the Flash Command
Register with the SPUI command
6) Wait for the FRDY bit to rise
7) Clear bit 16 of EEFC Flash Mode Register
Note: During the sequence, the software cannot run out of Flash (so it has to run out of SRAM).