Datasheet

330
SAM4S [DATASHEET]
11100E–ATARM–24-Jul-13
21.2.4.2 Read Handshaking
For details on the read handshaking sequence, refer to Figure 21-3 and Table 21-5.
Figure 21-3. SAM4SxB/C (64/100 pins) Parallel Programming Timing, Read Sequence
Table 21-4. Write Handshake
Step Programmer Action Device Action Data I/O
1 Sets MODE and DATA signals Waits for NCMD low Input
2 Clears NCMD signal Latches MODE and DATA Input
3 Waits for RDY low Clears RDY signal Input
4 Releases MODE and DATA signals Executes command and polls NCMD high Input
5 Sets NCMD signal Executes command and polls NCMD high Input
6 Waits for RDY high Sets RDY Input
NCMD
RDY
NOE
NVALID
DATA[7:0]
MODE[3:0]
1
2
3
4
5
6
7
9
8
ADDR
Adress IN Z
Data OUT
10
11
XIN
12
13
Table 21-5. 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