SAM7S256_14 Datasheet, PDF (139/775 Pages) ATMEL Corporation – ARM-based Flash MCU

20.3.4.1 Flash Read Command
This command is used to read the Flash contents. The memory map is accessible through this command. Memory
is seen as an array of words (32-bit wide). The read command can start at any valid address in the memory plane.
This address must be word-aligned. The address is automatically incremented.
Table 20-22. Read Command
Read/Write
DR Data
Write
(Number of Words to Read) << 16 | READ
Write
Address
Read
Memory [address]
Read
Memory [address+4]
...
...
Read
Memory [address+(Number of Words to Read - 1)* 4]
20.3.4.2 Flash Write Command
This command is used to write the Flash contents. The address transmitted must be a valid Flash address in the
memory plane.
The Flash memory plane is organized into several pages. Data to be written is stored in a load buffer that corre-
sponds to a Flash memory page. The load buffer is automatically flushed to the Flash:
• before access to any page than the current one
• at the end of the number of words transmitted
The Write Page command (WP) is optimized for consecutive writes. Write handshaking can be chained; an inter-
nal address buffer is automatically increased.
Table 20-23. Write Command
Read/Write
DR Data
Write
(Number of Words to Write) << 16 | (WP or WPL or EWP or EWPL)
Write
Address
Write
Memory [address]
Write
Memory [address+4]
Write
Memory [address+8]
Write
Memory [address+(Number of Words to Write - 1)* 4]
Flash Write Page and Lock command (WPL) is equivalent to the Flash Write Command. However, the lock bit is
automatically set at the end of the Flash write operation. As a lock region is composed of several pages, the pro-
grammer writes to the first pages of the lock region using Flash write commands and writes to the last page of the
lock region using a Flash write and lock command.
Flash Erase Page and Write command (EWP) is equivalent to the Flash Write Command. However, before pro-
gramming the load buffer, the page is erased.
Flash Erase Page and Write the Lock command (EWPL) combines EWP and WPL commands.
20.3.4.3 Flash Full Erase Command
This command is used to erase the Flash memory planes.
SAM7S Series [DATASHEET]
6175M–ATARM–26-Oct-12
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