SAM3S16C Atmel Corporation, SAM3S16C Datasheet - Page 385

• Manufacturer Part Number: SAM3S16C
• Manufacturer: Atmel Corporation

Specifications of SAM3S16C

• Flash (kbytes): 1024 Kbytes
• Pin Count: 100
• Max. Operating Frequency: 100 MHz
• Cpu: Cortex-M3
• # Of Touch Channels: 39
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 79
• Ext Interrupts: 79
• Usb Transceiver: 1
• Quadrature Decoder Channels: 2
• Usb Speed: Full Speed
• Usb Interface: Device
• Spi: 3
• Twi (i2c): 2
• Uart: 4
• Ssc: 1
• Sd / Emmc: 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 16
• Adc Resolution (bits): 12
• Adc Speed (ksps): 1000
• Analog Comparators: 1
• Resistive Touch Screen: No
• Dac Channels: 2
• Dac Resolution (bits): 12
• Temp. Sensor: Yes
• Crypto Engine: No
• Sram (kbytes): 128
• Self Program Memory: YES
• External Bus Interface: 1
• Dram Memory: No
• Nand Interface: Yes
• Picopower: No
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 1.8/3.3
• Operating Voltage (vcc): 1.62 to 3.6
• Fpu: No
• Mpu / Mmu: Yes / No
• Timers: 6
• Output Compare Channels: 6
• Input Capture Channels: 6
• Pwm Channels: 4
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

25.11 Data Float Wait States
25.11.1
Figure 25-17. TDF Period in NRD Controlled Read Access (TDF = 2)
11117B–ATARM–18-Oct-11
11117B–ATARM–18-Oct-11
READ_MODE
A[23:0]
Some memory devices are slow to release the external bus. For such devices, it is necessary to
add wait states (data float wait states) after a read access:
The Data Float Output Time (t
TDF_CYCLES field of the SMC_MODE register for the corresponding chip select. The value of
TDF_CYCLES indicates the number of data float wait cycles (between 0 and 15) before the
external device releases the bus, 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.
The data float wait states management depends on the READ_MODE and the TDF_MODE
fields of the SMC_MODE register for the corresponding chip select.
Setting the READ_MODE to 1 indicates to the SMC that the NRD signal is responsible for turn-
ing off the tri-state buffers of the external memory device. The Data Float Period then begins
after the rising edge of the NRD signal and lasts TDF_CYCLES MCK cycles.
When the read operation is controlled by the NCS signal (READ_MODE = 0), the TDF field gives
the number of MCK cycles during which the data bus remains busy after the rising edge of NCS.
Figure 25-17
assuming a data float period of 2 cycles (TDF_CYCLES = 2).
ation when controlled by NCS (READ_MODE = 0) and the TDF_CYCLES parameter equals 3.
D[7:0]
MCK
NRD
NCS
• before starting a read access to a different external memory
• before starting a write access to the same device or to a different external one.
illustrates the Data Float Period in NRD-controlled mode (READ_MODE =1),
tpacc
NRD controlled read operation
DF
will not slow down the execution of a program from internal
DF
) for each external memory device is programmed in the
TDF = 2 clock cycles
Figure 25-18
shows the read oper-
SAM3S16
SAM3S16
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