SAM7SE256 Atmel Corporation, SAM7SE256 Datasheet - Page 172

• Manufacturer Part Number: SAM7SE256
• Manufacturer: Atmel Corporation

Specifications of SAM7SE256

• Flash (kbytes): 256 Kbytes
• Pin Count: 144
• Max. Operating Frequency: 48 MHz
• Cpu: ARM7TDMI
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 88
• Ext Interrupts: 88
• Usb Transceiver: 1
• Usb Speed: Full Speed
• Usb Interface: Device
• Spi: 1
• Twi (i2c): 1
• Uart: 3
• Ssc: 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 8
• Adc Resolution (bits): 10
• Adc Speed (ksps): 384
• Resistive Touch Screen: No
• Temp. Sensor: No
• Crypto Engine: No
• Sram (kbytes): 32
• Self Program Memory: NO
• External Bus Interface: 1
• Dram Memory: sdram
• Nand Interface: Yes
• Picopower: No
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 1.8/3.3
• Operating Voltage (vcc): 3.0 to 3.6
• Fpu: No
• Mpu / Mmu: Yes / No
• Timers: 3
• Output Compare Channels: 3
• Input Capture Channels: 3
• Pwm Channels: 4
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: No

22.6.4.4
172
SAM7SE512/256/32
Chip Select Change Wait State
15) to be inserted and represents the time allowed for the data output to go to high impedance
after the memory is disabled.
Data float wait states do not delay internal memory accesses. Hence, a single access to an
external memory with long t
memory.
To ensure that the external memory system is not accessed while it is still busy, the SMC keeps
track of the programmed external data float time during internal accesses.
Internal memory accesses and consecutive read accesses to the same external memory do not
add data float wait states.
Figure 22-16. Data Float Output Delay
Notes:
A chip select wait state is automatically inserted when consecutive accesses are made to two
different external memories (if no other type of wait state has already been inserted). If a wait
state has already been inserted (e.g., data float wait state), then no more wait states are added.
1. Early Read Protocol
2. Standard Read Protocol
A[22:0]
D[15:0]
NCS
MCK
NRD
DF
will not slow down the execution of a program from internal
(1)
(2)
t
DF
6222F–ATARM–14-Jan-11