SAM7S256_14 Datasheet, PDF (130/775 Pages) ATMEL Corporation – ARM-based Flash MCU

20.2.5 Device Operations
Several commands on the Flash memory are available. These commands are summarized in Table 20-3 on page
126. Each command is driven by the programmer through the parallel interface running several read/write hand-
shaking sequences.
When a new command is executed, the previous one is automatically achieved. Thus, chaining a read command
after a write automatically flushes the load buffer in the Flash.
In the following tables, 21-6 through 21-18
• DATA[15:0] pertains to SAM7S512/256/128/64/321/161
• DATA[7:0] pertains to SAM7S32/16
20.2.5.1 Flash Read Command
This command is used to read the contents of the Flash memory. The read command can start at any valid
address in the memory plane and is optimized for consecutive reads. Read handshaking can be chained; an inter-
nal address buffer is automatically increased.
Table 20-6. Read Command
Step Handshake Sequence
1
Write handshaking
2
Write handshaking
3
Write handshaking
4
Read handshaking
5
Read handshaking
...
...
n
Write handshaking
n+1
Write handshaking
n+2
Read handshaking
n+3
Read handshaking
...
...
MODE[3:0]
CMDE
ADDR0
ADDR1
DATA
DATA
...
ADDR0
ADDR1
DATA
DATA
...
DATA[15:0]
READ
Memory Address LSB
Memory Address
*Memory Address++
*Memory Address++
...
Memory Address LSB
Memory Address
*Memory Address++
*Memory Address++
...
Table 20-7. Read Command
Step Handshake Sequence
1
Write handshaking
2
Write handshaking
3
Write handshaking
4
Write handshaking
5
Write handshaking
6
Read handshaking
7
Read handshaking
...
...
n
Write handshaking
n+1
Write handshaking
MODE[3:0]
CMDE
ADDR0
ADDR1
ADDR2
ADDR3
DATA
DATA
...
ADDR0
ADDR1
DATA[7:0]
READ
Memory Address LSB
Memory Address
Memory Address
Memory Address
*Memory Address++
*Memory Address++
...
Memory Address LSB
Memory Address
SAM7S Series [DATASHEET]
6175M–ATARM–26-Oct-12
130