SAM7S256_14 Datasheet, PDF (129/775 Pages) ATMEL Corporation – ARM-based Flash MCU

Table 20-5. Read Handshake
Step
Programmer Action
1
Sets MODE and DATA signals
2
Clears NCMD signal
3
Waits for RDY low
4
Sets DATA signal in tristate
5
Clears NOE signal
6
Waits for NVALID low
7
8
Reads value on DATA Bus
9
Sets NOE signal
10
Waits for NVALID high
11
Sets DATA in output mode
12
Sets NCMD signal
13
Waits for RDY high
Device Action
Waits for NCMD low
Latch MODE and DATA
Clears RDY signal
Waits for NOE Low
Sets DATA bus in output mode and outputs the
flash contents.
Clears NVALID signal
Waits for NOE high
Sets DATA bus in input mode
Sets NVALID signal
Waits for NCMD high
Sets RDY signal
DATA I/O
Input
Input
Input
Input
Tristate
Output
Output
Output
Output
X
Input
Input
Input
SAM7S Series [DATASHEET]
6175M–ATARM–26-Oct-12
129