[gentoo-embedded] arm or armeb?

[gentoo-embedded] arm or armeb?

[Jean-Marc Beaune]

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Hi,

I plan to cross-compile for an arm chip but how to know if I should choose
arm or armeb machine?

Thanks
-- 
Jean-Marc

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Re: [gentoo-embedded] arm or armeb?

[Karl Hiramoto]

Jean-Marc Beaune wrote:
> Hi,
>  
> I plan to cross-compile for an arm chip but how to know if I should
> choose arm or armeb machine?
>  
> Thanks
> -- 
> Jean-Marc
Depends.. Maybe give details of your bootloader, board, peripherals,
CPU, etc..


--
Karl

Re: [gentoo-embedded] arm or armeb?

[Jean-Marc Beaune]

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Hi,

The details:

- Processor: 16/32 bit *AT91SAM7X256* (ARM7TDMI-S™)
- 256 K Flash
- 64 K RAM
- USB 2.0
- Ethernet 10/100 Mbits
- 2 x RS-232
- ADC (10 bits), CAN, 2 x UARTs, TWI(I2C), 2 x SPI, 3 x timers 32bit, SSC, 4
x PWM, WDT, PDC (DMA)
- Frequency up to  55 MHz
- JTAG connector (ARM's 2 x 10 pins - ARM-JTAG compatible)
- Color TFT 128 x 128 pixels
- SD™/MMC™
- Mini-joystick
- Loudspeaker
- Audio input/output
- Crystal 18,432 MHz sur support
- RESET buton
- Dimension: 128 x 98 mm

The question is not specifically for this hardware but more "when to choose
arm and when to choose armeb" ?

Thank you


On Fri, Oct 3, 2008 at 1:05 PM, Karl Hiramoto <karl@hiramoto.org> wrote:

>  Jean-Marc Beaune wrote:
> > Hi,
> >
> > I plan to cross-compile for an arm chip but how to know if I should
> > choose arm or armeb machine?
> >
> > Thanks
> > --
> > Jean-Marc
> Depends.. Maybe give details of your bootloader, board, peripherals,
> CPU, etc..
>
>
> --
> Karl
>
>
>


-- 
Jean-Marc

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Re: [gentoo-embedded] arm or armeb?

[Karl Hiramoto]

Jean-Marc Beaune wrote:
> Hi,
>  
> The details:
>  
> - Processor: 16/32 bit *AT91SAM7X256* (ARM7TDMI-S™)
> - 256 K Flash
> - 64 K RAM
> - USB 2.0
> - Ethernet 10/100 Mbits
> - 2 x RS-232
> - ADC (10 bits), CAN, 2 x UARTs, TWI(I2C), 2 x SPI, 3 x timers
> 32bit, SSC, 4 x PWM, WDT, PDC (DMA)
> - Frequency up to  55 MHz
> - JTAG connector (ARM's 2 x 10 pins - ARM-JTAG compatible)
> - Color TFT 128 x 128 pixels
> - SD™/MMC™
> - Mini-joystick
> - Loudspeaker
> - Audio input/output
> - Crystal 18,432 MHz sur support
> - RESET buton
> - Dimension: 128 x 98 mm
>  
> The question is not specifically for this hardware but more "when to
> choose arm and when to choose armeb" ?
>  
> Thank you
>
AFIK,  you can't run linux on  an ARM TDMI with 64K of RAM  :-)


Using the same endianess as your bootloader will save you from byte
swapping.     If you can use the same endianness as the rest of your HW,
it will save the byte sapping operations and may make your system faster.


Some people prefer little endian, because other SW/ drivers has bugs on
little endian machines.


More about endianness you can probably get from googl'ing.

--
Karl

Re: [gentoo-embedded] arm or armeb?

[Jean-Marc Beaune]

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Thank you,

All right, but actually I didn't buy this hardware yet, I'm just
investigating and ceating crossdev toolchain.

So, not possible to know what's the difference between 'arm' and 'armeb'
machines?

Cheers,
/JM

On Fri, Oct 3, 2008 at 1:53 PM, Karl Hiramoto <karl@hiramoto.org> wrote:

> Jean-Marc Beaune wrote:
> > Hi,
> >
> > The details:
> >
> > - Processor: 16/32 bit *AT91SAM7X256* (ARM7TDMI-S™)
> > - 256 K Flash
> > - 64 K RAM
> > - USB 2.0
> > - Ethernet 10/100 Mbits
> > - 2 x RS-232
> > - ADC (10 bits), CAN, 2 x UARTs, TWI(I2C), 2 x SPI, 3 x timers
> > 32bit, SSC, 4 x PWM, WDT, PDC (DMA)
> > - Frequency up to  55 MHz
> > - JTAG connector (ARM's 2 x 10 pins - ARM-JTAG compatible)
> > - Color TFT 128 x 128 pixels
> > - SD™/MMC™
> > - Mini-joystick
> > - Loudspeaker
> > - Audio input/output
> > - Crystal 18,432 MHz sur support
> > - RESET buton
> > - Dimension: 128 x 98 mm
> >
> > The question is not specifically for this hardware but more "when to
> > choose arm and when to choose armeb" ?
> >
> > Thank you
> >
> AFIK,  you can't run linux on  an ARM TDMI with 64K of RAM  :-)
>
>
> Using the same endianess as your bootloader will save you from byte
> swapping.     If you can use the same endianness as the rest of your HW,
> it will save the byte sapping operations and may make your system faster.
>
>
> Some people prefer little endian, because other SW/ drivers has bugs on
> little endian machines.
>
>
> More about endianness you can probably get from googl'ing.
>
> --
> Karl
>
>
>
>
>
>
>
>


-- 
Jean-Marc

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Re: [gentoo-embedded] arm or armeb?

[Jason]

Jean-Marc Beaune wrote:
> The question is not specifically for this hardware but more "when to choose
> arm and when to choose armeb" ?

If your end application is network heavy, I would choose big endian
(which is Network Byte Order).  Outside of that, little endian is
preferred by a lot of folks simply because it gets more testing.  Most
drivers and apps are written on and for little endian architectures.

hth,

Jason.

Re: [gentoo-embedded] arm or armeb?

[Ned Ludd]

On Fri, 2008-10-03 at 13:34 +0200, Jean-Marc Beaune wrote:
> Hi,
>  
> The details:
>  
> - Processor: 16/32 bit AT91SAM7X256 (ARM7TDMI-S™)
> - 256 K Flash
> - 64 K RAM
> - USB 2.0
> - Ethernet 10/100 Mbits
> - 2 x RS-232
> - ADC (10 bits), CAN, 2 x UARTs, TWI(I2C), 2 x SPI, 3 x timers
> 32bit, SSC, 4 x PWM, WDT, PDC (DMA)
> - Frequency up to  55 MHz 
> - JTAG connector (ARM's 2 x 10 pins - ARM-JTAG compatible)
> - Color TFT 128 x 128 pixels
> - SD™/MMC™
> - Mini-joystick
> - Loudspeaker
> - Audio input/output
> - Crystal 18,432 MHz sur support
> - RESET buton
> - Dimension: 128 x 98 mm
>  
> The question is not specifically for this hardware but more "when to
> choose arm and when to choose armeb" ?


Just talked to a friend over at atmel. He confirms that you probably
want a arm-softfloat-linux-uclibc toolchain.

Generally the intel xscale chips tend to be the BE ones that we see on
arm. Otherwise most everything else is LE.


> Thank you
> 
> 
> 
> On Fri, Oct 3, 2008 at 1:05 PM, Karl Hiramoto <karl@hiramoto.org>
> wrote:
>         
>         Jean-Marc Beaune wrote:
>         > Hi,
>         >
>         > I plan to cross-compile for an arm chip but how to know if I
>         should
>         > choose arm or armeb machine?
>         >
>         > Thanks
>         > --
>         > Jean-Marc
>         
>         Depends.. Maybe give details of your bootloader, board,
>         peripherals,
>         CPU, etc..
>         
>         
>         --
>         Karl
>         
>         
> 
> 
> 
> -- 
> Jean-Marc
> 

Re: [gentoo-embedded] arm or armeb?

[Mike Frysinger]

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On Friday 03 October 2008, Jean-Marc Beaune wrote:
> So, not possible to know what's the difference between 'arm' and 'armeb'
> machines?

one is big endian, the other is little endian.  that's it.  if you dont know 
what endianness is, google for it ... i seem to recall wikipedia having a 
good page on it.
-mike

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