Hardware Description
7
up to 128 MB on-board NOR flash. It is connected to chip select zero (NCS0) of the micro-
controller.
The flash memory is made up of 1 or 2 ICs which have separated address spaces (see
Appendix C,
Address Map (Physical Address Space)
).
Typically NOR flash is organized in blocks, similar to hard disks. Typical block sizes are
64, 128, 256 KB. NOR flash can be read and written randomly. This makes it possible to
use NOR flash as execute in place (XIP) memory. To erase already written data, the whole
block containing the data has to be erased.
NOR flash is subject to limited write and erase cycles. These are typically 100.000 cycles
per block. So it is highly recommended to use wear levelling file systems.
4.3.2. SDRAM
The Panel-Card is equipped with 64MB SDRAM. Customer specific adaptations allow
configurations up to 128MB. The SDRAM is connected to chip select one (NCS1) of the
micro-controller.
SDRAM allows random access to any of its memory area and is volatile memory. SDRAM
has synchronous interface, that means it waits for a clock signal before responding to
control inputs and is therefore synchronized with the CPU bus. The clock is used to drive
a final state machine in the chip, which allows to accept new instructions, before the
previous one has finished executing.
4.3.3. EEPROM
The Panel-Card is equipped with a 256 bytes EEPROM, connected to the TWI (I
2
C).
EEPROM stands for Electrically Erasable Programmable Read-Only Memory and is
non-volatile memory, which is used to store small amounts of data like calibration or
configuration data. EEPROMS are byte-wise erasable, thus allowing true random access.
4.3.4. SRAM
The Panel-Card's micro-controller is equipped with 160 KB internal SRAM. The internal
SRAM can be accessed in one bus cycle and may be used for time critical sections of code
or interrupt handlers.
4.3.5. DataFlash
The Panel-Card 57 and Panel-Card 70 are equipped with 128 KB DataFlash
™
.
DataFlash is a Atmel
®
proprietary interface and is compatible to the SPI standard. Similar
to other flash chips it can be addressed page orientated and is available in sizes up to
8MB. Furthermore it is a possible boot media for the microcontroller.
4.4. Bus Matrix
The bus matrix of AT91SAM-controllers allows many master and slave devices to be
connected independly of each other. Each master has a decoder and can be defined
Содержание Panel-Card
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Страница 34: ...Panel Card Starterkit 28 Figure 6 3 Panel Card EVB Schematics Power Regulation ...
Страница 35: ...Panel Card Starterkit 29 Figure 6 4 Panel Card EVB Schematics Connectors ...
Страница 36: ...Panel Card Starterkit 30 Figure 6 5 Panel Card EVB Schematics HID ...
Страница 39: ...Panel Card Starterkit 33 Figure 6 8 Panel Card Connector Schematics USB Ethernet ...
Страница 40: ...Panel Card Starterkit 34 Figure 6 9 Panel Card Connector Schematics Power Regulation Connectors ...
Страница 49: ...Panel Card Dimensions 43 Appendix H Panel Card Dimensions Figure H 1 Panel Card 35 Dimensions ...
Страница 50: ...Panel Card Dimensions 44 Figure H 2 Panel Card 57 Dimensions ...