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11100B–ATARM–31-Jul-12
SAM4S Series [Preliminary]
20.2.3
Entering Programming Mode
The following algorithm puts the device in Parallel Programming Mode:
• Apply GND, VDDIO, VDDCORE 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
and
Figure 20-2. SAM4SxB/C (64/100 pins) Parallel Programming Timing, Write Sequence
0x0035
GSE
Get Security Bit
0x001F
WRAM
Write Memory
0x001E
GVE
Get Version
Table 20-3.
Command Bit Coding (Continued)
DATA[15:0]
Symbol
Command Executed
NCMD
RDY
NOE
NVALID
DATA[7:0]
MODE[3:0]
1
2
3
4
5
Summary of Contents for SAM4S Series
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