SAM9XE512 Atmel Corporation, SAM9XE512 Datasheet - Page 160

• Manufacturer Part Number: SAM9XE512
• Manufacturer: Atmel Corporation

Specifications of SAM9XE512

• Flash (kbytes): 512 Kbytes
• Pin Count: 217
• Max. Operating Frequency: 180 MHz
• Cpu: ARM926
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 96
• Ext Interrupts: 96
• Usb Transceiver: 3
• Usb Speed: Full Speed
• Usb Interface: Host, Device
• Spi: 2
• Twi (i2c): 2
• Uart: 6
• Ssc: 1
• Ethernet: 1
• Sd / Emmc: 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: Yes
• Adc Channels: 4
• Adc Resolution (bits): 10
• Adc Speed (ksps): 312
• 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): 1.65 to 1.95
• Fpu: No
• Mpu / Mmu: No / Yes
• Timers: 6
• Output Compare Channels: 6
• Input Capture Channels: 6
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: No

21.4
21.4.1
21.4.1.1
160
Arbitration
AT91SAM9XE128/256/512 Preliminary
Arbitration Rules
Undefined Length Burst Arbitration
FIXED_DEFMSTR field allows to choose a fixed default master provided that DEFMSTR_TYPE
is set to fixed default master. Please refer to the Bus Matrix user interface description.
The Bus Matrix provides an arbitration mechanism that allows to reduce latency when conflict
cases occur, basically when two or more masters try to access the same slave at the same time.
One arbiter per AHB slave is provided, allowing to arbitrate each slave differently.
The Bus Matrix provides to the user the possibility to choose between 2 arbitration types, and
this for each slave:
This choice is given through the field ARBT of the Slave Configuration Registers
(MATRIX_SCFG).
Each algorithm may be complemented by selecting a default master configuration for each
slave.
When a re-arbitration has to be done, it is realized only under some specific conditions detailed
in the following paragraph.
Each arbiter has the ability to arbitrate between two or more different master’s requests. In order
to avoid burst breaking and also to provide the maximum throughput for slave interfaces, arbitra-
tion may only take place during the following cycles:
In order to avoid too long slave handling during undefined length bursts (INCR), the Bus Matrix
provides specific logic in order to re-arbitrate before the end of the INCR transfer.
A predicted end of burst is used as for defined length burst transfer, which is selected between
the following:
1. Round-Robin Arbitration (the default)
2. Fixed Priority Arbitration
1. Idle Cycles: when a slave is not connected to any master or is connected to a master
2. Single Cycles: when a slave is currently doing a single access.
3. End of Burst Cycles: when the current cycle is the last cycle of a burst transfer. For
4. Slot Cycle Limit: when the slot cycle counter has reach the limit value indicating that the
1. Infinite: no predicted end of burst is generated and therefore INCR burst transfer will
2. Four beat bursts: predicted end of burst is generated at the end of each four beat
3. Eight beat bursts: predicted end of burst is generated at the end of each eight beat
4. Sixteen beat bursts: predicted end of burst is generated at the end of each sixteen beat
which is not currently accessing it.
defined length burst, predicted end of burst match the size of the transfer but is man-
aged differently for undefined length burst (See “Undefined Length Burst Arbitration” on
page iv.).
current master access is too long and must be broken (see
Limit Arbitration” on page
never be broken.
boundary inside INCR transfer.
boundary inside INCR transfer.
boundary inside INCR transfer.
161).
Section 21.4.1.2 “Slot Cycle
6254C–ATARM–22-Jan-10