AT32UC3A464 Atmel Corporation, AT32UC3A464 Datasheet - Page 66
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AT32UC3A464
Manufacturer Part Number
AT32UC3A464
Description
Manufacturer
Atmel Corporation
Datasheets
1.AT32UC3A0128.pdf
(377 pages)
2.AT32UC3A0128.pdf
(33 pages)
3.AT32UC3A0128.pdf
(159 pages)
4.AT32UC3A3128.pdf
(91 pages)
5.AT32UC3A3128.pdf
(1012 pages)
Specifications of AT32UC3A464
Flash (kbytes)
64 Kbytes
Pin Count
100
Max. Operating Frequency
66 MHz
Cpu
32-bit AVR
Hardware Qtouch Acquisition
No
Usb Transceiver
1
Usb Speed
Hi-Speed
Usb Interface
Device + OTG
Spi
6
Twi (i2c)
2
Uart
4
Ssc
1
Sd / Emmc
2
Graphic Lcd
No
Video Decoder
No
Camera Interface
No
Adc Channels
8
Adc Resolution (bits)
10
Resistive Touch Screen
No
Temp. Sensor
No
Crypto Engine
No
Sram (kbytes)
128
Self Program Memory
YES
Dram Memory
No
Nand Interface
Yes
Picopower
No
Temp. Range (deg C)
-40 to 85
I/o Supply Class
3.0 to 3.6
Operating Voltage (vcc)
3.0 to 3.6
Fpu
No
Timers
6
Output Compare Channels
6
Input Capture Channels
6
32khz Rtc
Yes
Calibrated Rc Oscillator
Yes
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
AT32UC3A464-CIUT
Manufacturer:
ATMEL
Quantity:
180
Part Number:
AT32UC3A464-CIUT
Manufacturer:
ATMEL/爱特梅尔
Quantity:
20 000
Company:
Part Number:
AT32UC3A464-U
Manufacturer:
XILINX
Quantity:
1
Company:
Part Number:
AT32UC3A464S-U
Manufacturer:
ATMEL
Quantity:
551
7. Memory Protection Unit
7.1
7.2
7.2.1
32002F–03/2010
Memory map in systems with MPU
Understanding the MPU
MPU interface registers
The AVR32 architecture defines an optional Memory Protection Unit (MPU). This is a simpler
alternative to a full MMU, while at the same time allowing memory protection. The MPU allows
the user to divide the memory space into different protection regions. These protection regions
have a user-defined size, and starts at a user-defined address. The different regions can have
different cacheability attributes and bufferability attributes. Each region is divided into 16 subre-
gions, each of these subregions can have one of two possible sets of access permissions.
The MPU does not perform any address translation.
An AVR32 implemetation with a MPU has a flat, unsegmented memory space. Access permis-
sions are given only by the different protection regions.
The AVR32 Memory Protection Unit (MPU) is responsible for checking that memory transfers
have the correct permissions to complete. If a memory access with unsatisfactory privileges is
attempted, an exception is generated and the access is aborted. If an access to a memory
address that does not reside in any protection region is attempted, an exception is generated
and the access is aborted.
The user is able to allow different privilege levels to different blocks of memory by configuring a
set of registers. Each such block is called a protection region. Each region has a user-program-
mable start address and size. The MPU allows the user to program 8 different protection
regions. Each of these regions have 16 sub-regions, which can have different access permis-
sions, cacheability and bufferability.
The “DMMU SZ” fields in the CONFIG1 system register identifies the number of implemented
protection regions, and therefore also the number of MPU registers. An AVR32UC system with
caches also have MPU cacheability and bufferability registers.
A protection region can be from 4 KB to 4 GB in size, and the size must be a power of two. All
regions must have a start address that is aligned to an address corresponding to the size of the
region. If the region has a size of 8 KB, the 13 lowest bits in the start address must be 0. Failing
to do so will result in UNDEFINED behaviour. Since each region is divided into 16 sub-regions,
each sub-region is 256 B to 256 MB in size.
When an access hits into a memory region set up by the MPU, hardware proceeds to determine
which subregion the access hits into. This information is used to determine whether the access
p e r m i s s io n s f o r t h e s u b r e g i o n a r e g iv e n i n M P U A P R A/ M PU B R A / M P U C R A o r i n
MPUAPRB/MPUBRB/MPUCRB.
If an access does not hit in any region, the transfer is aborted and an exception is generated.
The MPU is enabled by writing setting the E bit in the MPUCR register. The E bit is cleared after
reset. If the MPU is disabled, all accesses are treated as uncacheable, unbufferable and will not
generate any access violations. Before setting the E bit, at least one valid protection region must
be defined.
The following registers are used to control the MPU, and provide the interface between the MPU
and the operating system, see
Figure 7-1 on page
67. All the registers are mapped into the Sys-
AVR32
66