Datasheet

313
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
19.2.4.2 Read Handshaking
For details on the read handshaking sequence, refer to Figure 19-3 and Table 19-6.
Figure 19-3. Parallel Programming Timing, Read Sequence
19.2.5 Device Operations
Several commands on the Flash memory are available. These commands are summarized in Table 19-4 on page
311. Each command is driven by the programmer through the parallel interface running several read/write
handshaking 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.
NCMD
RDY
NOE
NVALID
DATA[15:0]
MODE[3:0]
Adress IN Z Data OUT X IN
ADDR
1
2
3
4
5
6
7
9
8 10
11
12
13
Table 19-6. Read Handshake
Step Programmer Action Device Action DATA I/O
1 Sets MODE and DATA signals Waits for NCMD low Input
2 Clears NCMD signal Latch MODE and DATA Input
3 Waits for RDY low Clears RDY signal Input
4 Sets DATA signal in tristate Waits for NOE Low Input
5 Clears NOE signal Tristate
6 Waits for NVALID low
Sets DATA bus in output mode and outputs
the flash contents.
Output
7 Clears NVALID signal Output
8 Reads value on DATA Bus Waits for NOE high Output
9 Sets NOE signal Output
10 Waits for NVALID high Sets DATA bus in input mode X
11 Sets DATA in output mode Sets NVALID signal Input
12 Sets NCMD signal Waits for NCMD high Input
13 Waits for RDY high Sets RDY signal Input