AT91SAM7S256D-AU Atmel, AT91SAM7S256D-AU Datasheet - Page 127

• Manufacturer Part Number: AT91SAM7S256D-AU
• Description: ARM Microcontrollers - MCU 256K Flash SRAM 64K ARM based MCU
• Manufacturer: Atmel
• Series: SAM7S256r

Specifications of AT91SAM7S256D-AU

• Rohs: yes
• Core: ARM
• Processor Series: AT91SAM
• Data Bus Width: 16 bit/32 bit
• Maximum Clock Frequency: 55 MHz
• Program Memory Size: 256 KB
• Data Ram Size: 64 KB
• On-chip Adc: Yes
• Operating Supply Voltage: 3 V to 3.6 V
• Operating Temperature Range: - 40 C to + 85 C
• Package / Case: LQFP-64
• Mounting Style: SMD/SMT
• Interface Type: 2-Wire, I2S, SPI, USART
• Length: 7 mm

20.2.3
20.2.4
20.2.4.1
Figure 20-3. SAM7S512/256/128/64/321/161Parallel Programming Timing, Write Sequence
Figure 20-4. SAM7S32/16 Parallel Programming Timing, Write Sequence
The following algorithm puts the device in Parallel Programming Mode:
Note:
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.
For details on the write handshaking sequence, refer to
• Apply GND, VDDIO, VDDCORE, VDDFLASH and VDDPLL.
• Apply XIN clock within T
• Wait for T
• Start a read or write handshaking.
Entering Programming Mode
Programmer Handshaking
Write Handshaking
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.
POR_RESET
DATA[15:0]
MODE[3:0]
MODE[3:0]
DATA[7:0]
NVALID
NVALID
NCMD
NCMD
NOE
NOE
RDY
RDY
1
1
POR_RESET
2
2
if an external clock is available.
3
3
Figure
4
4
20-3,
Figure 20-4
5
5
SAM7S Series [DATASHEET]
and
Table
6175M–ATARM–26-Oct-12
20-4.
127