Need help choosing microcontroller

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William Wuister Contact options for registered users 's Avatar (by Gravatar) posted on
October 12, 2003, 3:29 pm
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I need to find a microprocessor with the following requirements. I
currently use a PIC 16F876. I need to add a lot of software to the
product and don't have enough room in the pic.

   - at least 3 10-bit (or greater) a/d converters

   - 16 programmable digital i/o pins

   - 32-bit

   - execute from RAM

   - free C cross compiler

   - address 1 meg of memory (ROM and RAM)

   - pulse width output

   - programmable interrupt pins

   - timer interrupts

   - serial port registers and interrupts

   - fast: need to compute realtime physics using floating point math.

thanks,
William


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Tauno Voipio Contact options for registered users 's Avatar (by Gravatar) posted on
October 12, 2003, 4:06 pm
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Re: Need help choosing microcontroller

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Except for the A/D converters, the thing could be an Atmel AT91, e.g.
AT91R40008. It's based on the ARM7TDMI 32-bit core and contains plenty for
your other requirements.

IMHO, external A/D's are much easier to handle because of less digital
noise. I'd use any of the SPI converters with the AT91. It's not difficult
to bit-bang them on the AT91 I/O ports.

The GNU toolchain (gcc, as, ld, objcopy, gdb ...) supports the chip.

HTH

Tauno Voipio
tauno voipio @ iki fi



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Stef Contact options for registered users 's Avatar (by Gravatar) posted on
October 12, 2003, 6:35 pm
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Re: Need help choosing microcontroller
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The philips LPC2106 has 64kB RAM and 128kB FLASH onchip, but no ADC, has
I2C and SPI though so you could use an external ADC. ARM core, so gnu
compiler available.

The AT91M55800 has internal ADC but needs external memory (128MB max),
also ARM core. I think atmel may have closer matching parts, have a look.

--
Stef

Blessed are they who Go Around in Circles, for they Shall be Known as Wheels.

Ulf Samuelsson Contact options for registered users 's Avatar (by Gravatar) posted on
October 13, 2003, 9:05 am
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Re: Need help choosing microcontroller
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Small comparision

AT91M55800:  Internal ADC, 8 kB SRAM, 33 MHz
AT91M40008:  External ADC, 256kB of SRAM, 66 MHz.  (60 MIPS when internal
operation)
AT9RM9200:   External ADC, 16 kB SRAM, 16k+16k cache, Burst Flash, SDRAM,
180 MHz is even  better.

--
Best Regards
Ulf at atmel dot com
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William Wuister Contact options for registered users 's Avatar (by Gravatar) posted on
October 13, 2003, 12:28 pm
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Re: Need help choosing microcontroller

It seems that Atmel ARM processors are the consensus. So, that's what
I'll go with. I did a project with a 68332 once. That was also a
possibility for me. I really liked that chip.

thanks,
William


On Mon, 13 Oct 2003 11:05:38 +0200, "Ulf Samuelsson"

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Ian McBride Contact options for registered users 's Avatar (by Gravatar) posted on
October 14, 2003, 12:38 am
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Re: Need help choosing microcontroller

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Then you might also look at the Motorola Coldfire chips, like the MCF8252
and MCF5272.




William Wuister Contact options for registered users 's Avatar (by Gravatar) posted on
October 14, 2003, 10:58 pm
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Re: Need help choosing microcontroller
I'm leaning toward the Atmel AT91R40008. I have a couple of follow-up
questions about this.

Does it have a hardware floating point coprocessor? I didn't see that
it did, but I haven't yet found full documentation on the processor.
Where can I find a full instruction set description?



Tauno Voipio Contact options for registered users 's Avatar (by Gravatar) posted on
October 15, 2003, 6:03 am
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Re: Need help choosing microcontroller

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No. It's a pretty pure RISC without even a divide instruction.

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There are documents on the ARM site.

Also, the ARM7TDMI manual is on the Atmel site documentation part.

For complete information, get also the AT91R40008 and AT91X40X data sheets
from the same Atmel location.

HTH

Tauno Voipio
tauno voipio @ iki fi




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William Wuister Contact options for registered users 's Avatar (by Gravatar) posted on
October 15, 2003, 12:13 pm
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Re: Need help choosing microcontroller

So, is there an ARM based processor with integrated floating point?
That's what I'm looking for.

thanks,
William

On Wed, 15 Oct 2003 06:03:32 GMT, "Tauno Voipio"

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