Datasheet

Table Of Contents
127
SAM7S Series [DATASHEET]
6175M–ATARM–26-Oct-12
20.2.3 Entering Programming Mode
The following algorithm puts the device in Parallel Programming Mode:
Apply GND, VDDIO, VDDCORE, VDDFLASH and VDDPLL.
Apply XIN clock within T
POR_RESET
if an external clock is available.
•Wait for T
POR_RESET
Start a read or write handshaking.
Note: After reset, the device is clocked by the internal RC oscillator. Before clearing RDY signal, if an external clock (> 32
kHz) is connected to XIN, then the device switches on the external clock. Else, XIN input is not considered. A higher
frequency on XIN speeds up the programmer handshake.
20.2.4 Programmer Handshaking
An handshake is defined for read and write operations. When the device is ready to start a new operation (RDY
signal set), the programmer starts the handshake by clearing the NCMD signal. The handshaking is achieved once
NCMD signal is high and RDY is high.
20.2.4.1 Write Handshaking
For details on the write handshaking sequence, refer to Figure 20-3, Figure 20-4 and Table 20-4.
Figure 20-3. SAM7S512/256/128/64/321/161Parallel Programming Timing, Write Sequence
Figure 20-4. SAM7S32/16 Parallel Programming Timing, Write Sequence
NCMD
RDY
NOE
NVALID
DATA[15:0]
MODE[3:0]
1
2
3
4
5
NCMD
RDY
NOE
NVALID
DATA[7:0]
MODE[3:0]
1
2
3
4
5