Arcom VIPER, Техническое руководство

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VIPER Detailed hardware description
PXA255 processor
The PXA255 is a low power ARM (version 5TE) instruction set compliant RISC
processor. The PXA255 does not include a floating-point unit. The device does,
however, contain a DSP co-processor to enhance multimedia applications.
The 400MHz PXA255 is driven by a 3.6864 MHz clock, which generates all the high-
speed clocks within the device. The default run mode frequency is 400MHz for
embedded Linux, VxWorks and Windows CE .NET. Currently embedded Linux and
VxWorks supports changing the operating frequency and Windows CE .NET will
provide support shortly. Please refer to the relevant operating system technical manual
to select an alternative operating frequency.
The processor has two supply inputs: I/O and core generated on the VIPER from the
main +5V supply input. The I/O supply is powered from +3.3V, and the core is powered
from a +1.06 to +1.3V adjustable supply. See the section
Processor power
management , page 55 , for operation details.
The PXA255 has an integrated Memory and CompactFlash Controller with 100 MHz
Memory Bus, 32 KB data and 32 KB instruction caches and 2 KB Mini data cache for
streaming data.
The PXA255 provides up to 85 GPIO pins, many of these have been configured for
alternative functions like the AC’97 and PC card / CompactFLASH interfaces. Details of
these pin configurations are provided in the section
PXA255 GPIO pin assignments ,
page 17 .
The PXA255 also has the following features that can be used on the VIPER:
Peripheral Control Module:
•
•
- 16 channel configurable DMA controller.
- Integrated LCD controller with unique DMA for fast color screen support.
- Serial ports including AC’97, three UARTs, and enhanced USB end point
interface.
System Control Module:
- General-purpose interruptible I/O ports.
- Real-time
clock.
- Watchdog.
- Interval
timers.
- Power management controller.
- Interrupt
controller.
- Reset controller.
- Two on-chip oscillators.
The PXA255 processor is packaged in a 256-pin PBGA, which is attached to the board
during the assembly process.
The PXA255 processor is a low power device and does not require a heat sink for
temperatures up to 70
°
C (85
°
C for the industrial variant).
© 2004 Arcom Issue H
16