Being a beginner in all this, I have no experience / reference to be able to
put product names to these capabilities. Would you "name names" please? I'll
create a diversion to take all the flames while you do that... (c:
I thought 51's had a decent stack and register structure. I've used them
since 1976... (Intel 8731?) I found the instruction set entirely logical and
usable with an easy learning curve.
The OP is a beginner and needs something simple to get going with. The 51
does what it says on the tin. The Dallas 450 version ,you can get up and
running in an afternoon with a couple of support chips.
68000 series has pretty symmetric instruction set (orthoganol).
ie Moving from register to memory and vice versa is symmetric there are
minimal exceptions. There are microntroller variants of processors that
use 68000 instruction set.
Having a lot of registers is a bonus, 16 to 32 is ideal for the vast bulk
on microcontroller apps, can get away with 4 or even 2 if you are keen.
Basically, for a beginner, you'd want an instruction set that works 'both
ways' with registers, memory and IO ports, you dont want one with lots of
lumpy exceptions or stack size restrictions or memory address or io
restrictions - because if you are doing assembler you dont want to worry
about that many until you are proficient, which usually happens fairly soon
once you get stuck into it...
* VK/VL Commodore FuseRails that wont warp or melt with fuse failure indication
GEEEZ -- I gave up writing ASM for the 1st cut about 20 years ago -- the
compilers available even then were efficient enough that you only needed to
get down and dirty for the most critical timing dependent code.. there just
isnt a point in starting off with ASM considering that C maps almost 1-to-1
to most assembly languages for most of its internal features. And the WinAVR
C compiler makes it real easy to embed ASM right in the C code so I can do
it in C first, then convert just the parts that need it in place with a
perfectly working and tested "flow chart" right in front of me.
In addition.. for 99% of apps, you'll never bother with ASM because the
compiled code will work right off and nothing will need to be hand
optimized... you've gotta be right on the ragged edge of what the chip is
capable of before ASM is going to help you, and 99% of apps wont even come
close to that limit.
Its cheaper for me to buy a stick of chips with the quantity discount than
it is to buy the minimal chip that will do the job each time I come up with
a new project :) Plus I dont have to wait for the new chips to show up --
always have a few on hand :) I've probably got 4 or 5 flavors of AVR hangin
around... from 18 pin to 40 pin with various flash/ram/eeprom combos -- I
just use whatever I got that will do the job at all :) havent run into a
project yet where the processor was out of the idle loop more than 50% of
the time :) hehehe I guess I could meet your criteria by cranking the clock
speed down a bunch !! but for me -- the processor has only 2 speeds -- the
fastest it will do without a crystal -- and the fastest it will do with one
:) I dont see the point of putting a slower crystal in then having to bust
nuts to make the code work.
hehehehe ---- If I only used my Dual 2.8g hyperthreaded Xeon with 4 gigs ram
to read newsgroups -- welllll :) but between editing DVD masters,
programming AVRs and C#, designing databases, apps and websites, editing
graphics, controlling my CNC mill, running 8-10 hour spice simulations on
10kw power supplies, etc -- I tend to keep this sucker pretty busy most of
the time :)
I dont have a (working) laptop at the moment -- but the pub sounds like a
good idea !!
This gets back to the "intended-application" discussion.
While it's nice to have a "family" of chips you've spent the better
part of your adult engineering life understanding, there are times
when you simply must stretch the envelope.
Like my current project for instance.
It has to "rob" power from something that was never intended to
I need to powerdown more than roughly 90% of the time, drawing no more
than a few uA.
And not much more than 100uA for the other 10% of the time.
Oh, and for that, the clock speed is barely 20kHz (+/- 10%).
I think "MIPS" is a pipe dream for this one.
I need uA in stand-by. Full speed (Usb or Serial) while connected.
So, I need it very slow and very fast. For Serial, Avr tops at 19,000
and Arm tops at 920,000 baud. Avr has Usb option but Arm hasn't.
The attiny2313 "data sheet" suggests it should be capable of 250Kbps
(asynchronous serial) at 2mhz
With a 2MHz clock 38400 baud isn't really an option on that hardware,
35714.3 or 41666.7 are the closest choices.
If you reduce the clock to 1.8432 Mhz (should be a standard size)
38400.0 is available (as are the other standard speeds upto 230400)
Not with the uart running I hope!
How does it manage that? 920K doesn't divide 20M, is there an internal PLL
Anyway it seems kind of slow :^)
Some people bit-bang USB at 1.5Mb/s on 12Mz AVRs. (as a non-interruptable
foreground task) again the trick is to pick a clock rate that's a
sufficiently high multiple of the data rate.
The 32Khz are you do that using the watchog and prescaler? 128KHz/4 or an
It looks like the internal RC can be pulled across an octave in 256 steps
so getting within 0.5% of some multiple of 38400 should be possible.
yeah, it'd need an external clock if it wanted to do serial at standard
rates and bit-bang the usb
someone was saying that the AVRs are standing still while the PICs are
advancing, I'm not seeing that. the ATTiny2313 datasheet has 3 times as many
pages as the AT90S2313, and it seems like it has three times the features too,
that part's been available for a while now but I see they are upgrading
other parts to 20Mhz and I assume the other new 2313 fearures too
still binary and electically compatible with the at90s2313 AIUI.
(except for parallel programming)
That would be a high duty cycle for a phone line, unless you need to wake up
frequently to see if touch tones are being sent.
Yep, sounds right in line for a PIC though. 12F683 (my new favorite) ~500
uA at 5V running full tilt on the internal oscillator (8MHz, 1% accuracy),
11uA at 32KHz (2V). Change speeds on the fly. Who needs to sleep? ;-)
You can sleep if you want, bit it'll cost you 50nA.
They don't really need it, (most) kids want to show off to other kids.FYI I
read this newsgroup with a celeron 2.4 512 megs geforce 4 mx 440 64 MB QDI
848 p 80 GB IDE Hitachi 17" crt.The only advanced gimmick I have is DSL.Yes,
and with that comp I play doom 3, quake 4, half life 2, world of warcraft,
print digital photos, edit dvds, do my autocad drawings and of course keep
my contact with some fine internet fellows;-)
major in electrical engineering
mechanized infantry reservist
dimtzort AT otenet DOT gr
Names! Names! Names! (please). I agree with what you say, but I need the
benefit of y'all's experience. Which controller "variants of processors that
use 68000 instruction set" and which don't do "lumpy exceptions or stack size
Just need to know what name to call these lovelies by.
68HC11, but it's old. I'll bet the 'HC12 and 'HC16 (do they still make
those?) are good.
AVR, if you don't mind wimpy pins.
The TI MSP430 -- the small ones at least have oodles of pin drive, they
appear to have a rational architecture, they're fast, and you can get a
complete development system from TI for $20.
ARM, if you don't mind wading through all the different versions that
are available to find what you want (check those pin drive capacities!).
The instruction set is rational, but only in a screwy, RISC sort of
way. The capabilities are HUGE, and so is the set of mistakes you can
make -- I wouldn't recommend it for a beginner.
PowerPC -- Freescale has embedded versions. Same snarky comment about
the instruction set as ARM, but still way better than a PIC.
Those are the ones that I'm familiar with.
Oh -- _not_ the Intersil/RCA 1802, unless you want to be an ace assembly
language programmer. It was the very first processor I ever worked
with, in 8th grade. I call it a NHISC -- Never Had an Instruction Set.
I don't know if it's still around, but for quite a while it was the
king of little space apps, because it had a huge geometry that could
absorb cosmic rays without even noticing that they were there.
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