Advice on switching microntrollers

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Ok, flamewar time I guess.

I am looking to explore new microcontrollers because the ones I have
under my belt are coming up short for what I need.  I have a lot of
experience with the 16 series of PICs from Microchip, I have played
with basic Stamps (I, II, SX), some experience with Motorola's HC11,
HC12 and HC16 series.  Currently I use Atmel's AVR (Atmega128) at work.
 But in trying to branch out and find a better or at least alternate
choice I turn to the advice of those who already have experience with
something else.

My requirements are:
*External interrupts
*PWM outputs (everything I've used so far has done these with hardware
timers.  seems nice)
*ADC inputs 8 bit resolution minimum, 10 or 12 bits nice.
*I2C or whatever that manufacturer likes to call it.  Atmel calls it
TWI so they don't have to pay license fees to Philips or something.
*UART(s)
*hardware SPI
*JTAG nice but not required
*CAN support would be VERY nice but not absolutely required
*In circuit serially programmable
*Support for a secondary external crystal (32KHz for timekeeping)
*C friendly (and no, PICs do NOT fit this...)  As a side note, GCC
compatible is a BIG plus.  Paying out the nose for 3rd party compilers
is a killer.
*SMALL!!!  I'd like to keep it smaller than an Atmega128 which is
64TQFP at 16x16mm.
*Low power (sleep modes are good).  We're trying to stay below 10-20 mA
for full speed execution and <1mA for a sleep or low power mode.

My coworker would also like a cheap/free set of programming and debug
IDEs for it.  I have experience with MPLab from Microchip and AVRStudio
from Atmel so anything that good or better would be fine.  Just
something graphical to step through code, set breakpoints, simulate,
etc.

So anything not made of unobtanium that you guys would recommend?
Thanks!
-Will


Re: Advice on switching microntrollers

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I don't see what you have against unobtainium. It is a wonderful material.
It's just a shame it's so expensive. ;>

Have you looked at the MSP430 series from TI? Quite a bit of your
requirements list covered (although I think not all). 14 bit ADC's on some
processors in the family 12 bit on others.

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Re: Advice on switching microntrollers
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  Since you already have a reasonable range of 8 bit uC's, there would
seem little point adding another one. just to get a learnng curve....

  I'd look at the ARM families, Philips presently have the
cheapest/smallest start at $1.50, and Atmel have ones with Ethernet.
  Pretty much everyone makes some ARMxx variant, including Freescale and
TI.

-jg





Re: Advice on switching microntrollers
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...

Or, work on new approaches to task sharing. What ever happened to
The Connection Machine? I remember reading a thing in some mag, where
some guy said, (I paraphrase) "Well, the only problem we have now is
how to program the thing!" "Ah, but we have an endless supply of
programmer flesh - undergrads!"

But nothing ever seems to have come of it.

Thanks,
Rich


Re: Advice on switching microntrollers
Danny Hillis is having more fun building crazy 10000 year clocks, and big
ole robots, out of Glendale CA, at a place called Applied Minds.




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Task Sharing (was Re: Advice on switching microntrollers)

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Aahhhhhhhh!!!!, dreams of hypercubes....

There have been some interesting approaches to programming meshed and close
coupled processor cores. Some of them have been reported in The Journal for
Forth Applications Research. Forth was apparently the bring-up language for
one of the MPP's.

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Re: Advice on switching microntrollers


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I think you hit the nail on the head. Programming and programmers. As I
recall, the original CM-1 was a large array of 32,000 or so 1-bit
processors, which I think no one could effectively program. Then,
around 1987, they changed over to the CM-2 with the 1-bit processors
being replaced with a bunch of Natl Semi 32032 [a dead horse] 32-bit
chips on plugin boards. Intel and maybe TI and some others also had
various hypercube architectures, but I think they all died out since
their target market was the same people buying large NEC and IBM
supercomputers. Couldn't compete on doing things the old way.


Re: Advice on switching microntrollers
Hello Will,

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Nah. Just different opinions.

I'd side with Paul. The MSP430 series is really nice and their ALU runs
at 16 bits. Almost feels like getting into that new V8, including the
financial pain that comes with that. Don't expect them to be much under
a Dollar for the bar bones versions, no matter what TI marketeers claim.
Once you want ADC and some other niceties expect to pay over $2. So,
right now they can't play in the Atmel price range.


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All uC I have seen so far do it in hardware timers, or not at all. The
MSP is geared nicely here but again it uses the timer. For truly
dedicated PWM you need to look at DSP.


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This is where the MSP430 truly excels. I don't know if any other uC can
go that low in power. They even have a mode where you can keep a RTC
running yet it sips only a couple uA or so.

Regards, Joerg

http://www.analogconsultants.com

Re: Advice on switching microntrollers

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NEC V850 series. Unfortunately the tools I used were Greenhills. Expensive
crap, but V850 might be supported by GCC now.

John



Re: Advice on switching microntrollers

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a list of current targets for gnu/gcc
http://gcc.gnu.org/install/specific.html


Re: Advice on switching microntrollers

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There is a east MSP430 missing msp430gcc is available too. AFAIK there is a
HOWTO out with eclipse as IDE. Feels like CCE from TI ;-)

Marte



Re: Advice on switching microntrollers
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[shopping list snipped]

Get the biggest FPGA or CPLD you can, and write the one of your
dreams. ;-P

Personally, I rather like microprogramming, albeit I'm kind of a
solution in search of a problem in that respect. For example, my
first real computer was a "Scelbi 8-H", which had an intel 8008
and 256 bytes of RAM. Eight toggle switches and three pushbuttons
on the front panel, and three rows of 8 LEDs: H, L, and M. The
buttons were, "Interrupt", "Step", and "Run". They weren't debounced,
which was a very powerful learning experience! ;-)

I guess the point is, the 8008 "assembly language" mapped almost
character for character onto the machine instructions, which, when
I saw the diagram of the architecture of the 8008 <googles> Ah,
rats. Most of the google hits are about history and crap - I was
hoping for a diagram. But it's so freaking simple that the program
is the equivalent of a microprogram. Like, the instructions are in
octal, two bits of op code, and three bits each for usually the
destination register (A,B,C,D,E,H,L,M) and three for the source
register (see above.) "3" was the opcode for "move". And when
you look at the architecture diagram of the 8008, you can see that
when the instruction enters the black box, it's split up into
opcode, destination, and source - which go directly to the data
selectors on the inputs or outputs, as designated! Oh, of course,
there are other opcodes, but they had sub-codes, which still only
needed one more level of decoding - my point being, that the
program for an 8008 was, essentially, a microprogram. :-)

Cheers!
Richh

Cheers!
Rich


Re: Advice on switching microntrollers
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For more direct-mapped nostalgia, compare the instruction
set of Data General Nova and the Texas Instruments SN74181
ALU chip.

Another pretty easily microcoded example is the Digital
PDP-11.

--

Tauno Voipio
tauno voipio (at) iki fi


Re: Advice on switching microntrollers

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I had an opportunity to use an editor on a PDP-11 and cross-assembler
to write some test stuff for an IMP-16:
http://www.bitsavers.org/pdf/national/imp16/4200036A_IMP16P_Descr_1974.pdf
The company had the naked boards in stock, to use in another thing; they
didn't have that box.
There's more stuff:
http://www.bitsavers.org/pdf/national/imp16 /
And, I believe I've seen the 74181s, or maybe AM2903s, on a PDP-11's CPU
board. I also once worked on an all-TTL "microprogrammable processor",
but it was 32 bits, and was used to test disk drives. That one had even
TTL RAM. The instruction cycle was 168 ns, which was unheard of at the
time. And, the thing that really makes the microprogram stand out as a
microprogram is the "next instruction" field in the instruction. The
G-15's machine language was like that too, but that was for timing,
since all of the memory was circulating on a magnetic drum.

Ah, I nostalge. <sigh> Sorry.

Cheers!
Rich




Re: Advice on switching microntrollers



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You do of coursde realise that I2C and SPI just need a couple of port pins.

There's nothing special about the hardware. Simply write your own device
handler.

Graham


Re: Advice on switching microntrollers
On Sat, 22 Oct 2005 00:08:36 +0100, Pooh Bear

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If one need to bit-bang these ports, then one should just note the I/O
speed of the MCU. On many of the new ARM MCUs, the possible I/O
toggling speed is a lot lower for a specific system clock speed than
for the 8-bit MCUs.

Regards
  Anton Erasmus



Re: Advice on switching microntrollers


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How is that so?  I mean, is there some kind of long propagation delay or
what?  I have played around with PICs for years, but I have been gaining
interest in the ARM micros.  This sounds like a serious issue to me.


Re: Advice on switching microntrollers
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ARMs typically use the AMBA bus where you connect the CPU to the 32 bit
Advanced System Bus (ASB)
and then there is a bus bridge to an Advanced Peripheral Bus (APB).
The Bus Bridge will add delays so you find bit banging will take 5-6 clocks
at best due to delays.
The Philips LPC was so bad at this, that some new parts have the PIO on the
ASB bus instead of on the APB bus.
The AT91SAM7 is limited by the I/O buffers but H/W can shuffle bits at 25-30
Mbps.


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Ulf Samuelsson
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Re: Advice on switching microntrollers

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The MLF package is a LOT smaller (9 x 9 mm), and not that difficult to
work with. (Much easier than BGA).

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Look at the various new generation of ARM based MCUs. There are quite
a lot available from manufacturers such as Philips, Atmel, ST, Analog
Devices, TI and Freescale.

Regards
  Anton Erasmus


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http://www.cypress.com

Click on PSoC Mixed-Signal Controllers.

The in-circuit emulator is not free.

Cheers,
John

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