Datasheet

SAM4E [DATASHEET]
Atmel-11157D-ATARM-SAM4E16-SAM4E8-Datasheet_12-Jun-14
420
22.3.3 Entering Programming Mode
The following algorithm puts the device in Parallel Programming Mode:
 Apply the supplies as described in Table 22-1.
 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.
22.3.4 Programmer Handshaking
A 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.
22.3.4.1 Write Handshaking
For details on the write handshaking sequence, refer to Figure 22-2, Figure 22-3 and Table 22-4.
Figure 22-2. Parallel Programming Timming, Write Sequence
0x0035 GSE Get Security Bit
0x001F WRAM Write Memory
0x001E GVE Get Version
Table 22-3. Command Bit Coding (Continued)
DATA[15:0] Symbol Command Executed
NCMD
RDY
NOE
NVALID
DATA[15:0]
MODE[3:0]
1
2
3
4
5