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DPRG: Real good riddle.

Subject: DPRG: Real good riddle.
From: Kevin Ross kevinro at nwlink.com
Date: Sun Jul 27 13:45:27 CDT 1997

> A question:
> >From what you have listed here, the 68hc812E2 seems to be of much better

> advanced than PIC. Wel then I was wondering...is it easier to get started

> with or simply CHEAPER to start with. 

Short answer: The 68HC11 is easier and cheaper

Long answer: I believe it will be easier to start with a CISC type
processor. The 68HC11 has 4 registers you can work with, including a couple
of 16-bit ones. The PIC has exactly one 8-bit working register. The 68HC11
has 256 bytes of memory that are arranged in a usable format. The PIC has
36 bytes of memory. The CISC instruction set has a better instruction mix.
You can do things like multiply, divide, plus a host of bitwise
instructions. The PIC has extremely primative instructions. The 68HC11 is
more like 'other' processors than the PIC is. Things you learn to do on the
68HC11 will be closer to what you would learn on the 8051, 68K, or pretty
much any other processor. 

> Another Q:
> You have listed that there is a C compiler for that chip ? is it free too

> or you have to purchase it ?

Micro-C is a free compiler you can get from the net. There is also the
Imagecraft C compiler which is about $100. It is a good compiler with an
IDE environment. 
> Another Q:
> That SBasic...is it a interpreter or Compiler ?And what is the difference

> between the PBasic Compiler and SBasic ?

SBasic is a basic compiler (generates native code) that was written by Karl
Lunt. It is free, and allows you to write some pretty sophisticated BASIC
program. http://www.seanet.com/~karllunt/tips.htm

> Anoteher Q:
> What did you mean by : "Battery driven" ?

You don't need any AC adapters to program or operate the board. Just a 5 to
6v battery. You can program it on an airplane with a laptop (having done
that many times!). 
> Anotehr question :
> Is there one place where I can puchase all this stuff ?

Sure. I will sell you an assembled Botboard with the 68HC811E2 for $40.
Send me some email. 
> Antother Q:
> Will I get better , worse, the same performance than PIC ?

Short answer: You won't notice the difference
Long answer: For some applications, the PIC is extremely fast. For other
applications, it isn't. The PIC executes millions of instructions per
second. However, those instructions typically don't do much! The 68HC11
does close to a million instructions (depending on which instructions you
use), but those instructions typically are more feature rich. In the end,
the 68HC11 is more than fast enough for most robotic applications. Combine
it with the more functional features of the chip, and it is a better
general purpose chip.  

> Another Q :
> IS this chip compatibile enough to to able to "talk" over the serial port

> with the PIC controllers ?

I don't know what you mean by this. It does have a standard serial port
that outputs standard async serial bits. Many of the pics, the 16C84 in
particular, don't have serial ports at all. You have to write your own
serial port routines in software. 

> Another Q:
> what is that BotBoard I ($6 for board, about $6 for misc parts) ?

> Another Q:
> > Serial Cable (MAX232 + connectors = $5) <- what do you mean "MAX232 +
connectors"(will I have to but the connector together on my own ?)


> Another Q:
> Can you run this processor from the batteries  and if so what kind and 
> how long (if in the sleep mode)

Absolutely. How long depends on the size of your batteries, which features
you have turned on in the chip, etc. The BotBoard draws about 8mA of
current with the A/D charge pump running. If you need longer battery life,
you can slow the clock down. In single chip STOP mode, it draws about 50uA.

> Another Q:
> The PIC hardware comes FULLY assembled so there is no screwing(maybe 
> except the connectors to the back of the computer) or soldering.
> Is it the same with Motorola Chip ?

Well, the PIC hardware can be bought fully assembled, which appears to be
what you are asking for. You can buy FULLY assembled boards for almost any
CPU. If you don't want to solder, it will cost you more. Check out the back
sections of any Circuit Cellar magazine.
(http://www.circellar.com/public/default.htm). Micromint, New Micros
(www.newmicros.com), Axiom (www.axman.com), Zorin (http://zorinco.com/) all
have FULLY assembled boards. And, of course, the price goes up with the
more you have other people do for you. 

> Another Q:
> Since it has EEPROM can you erase the ROM witht he programmer or you have

> to have s pecial eraser ?

On the 68HC11, No hardware required. It is all done via the serial port of
the PC. The PIC requires a programmer.

> Another Q:
> What timing circuit do I need for that chip ? (Becaus eif I'm correct the

> to PIC  you can connect the right crystal and that baby flies ?

Identical to the 68HC11. 

> Another Q:
> Since you said the PIC is not feature rich...so why the hell is this 
> thing so popular ?????

In the right hands, and PIC can really fly. So can the 68HC11. If you are
just starting, I am suggesting that the PIC isn't the right thing to start
with. It requires knowledge and a good mental toolbox of tricks to get it
to work well. The PIC is a cheap, fast, small CPU with limited scope that
works extremely well for specialized jobs. It is a poor choice as a general
purpose CPU. If you are learning, you want a general purpose CPU. 

> Another Q:
> Will I have to make my own programmer or is tehr eon you can buy ?
> (since my budget is really  tight I don't really want to fry several 
> chips before realizing that one pin in my programmer is connectred wrong)
> I have heard stories that some people have messed up their computers by 
> connecting something "mistakenly" 

You program the 68HC11 with via the serial port. All you need is a serial
port adapter, which is a MAX232 RS-232 <=> TTL converter. That is one of
the advantages of the 68HC11. The specialized hardware is not required,
other than the level shifter which you can use on any CPU. 

> GOD DAMN THIS PROCESSOR IS 40 pinner. Hell I don't know if you ever heard

> it: " If you can't afford to blow it up, then don't use it at ALL"

Huh? What 40 pinner?  The 68HC11 usually comes in a 52-PLCC configuration.
You typically put it in a socket on a development board like a BotBoard I. 

I have yet to see anyone blow up a 68HC11. It would be interesting. Your
quote about blowing things up sounds quite macho, but is very poor advice. 

> I am simply little bit afraid that I would spend my money and the first 
> this I'll see from that processor would be a grey smoke. The first thing 
> I would attempt would be probably a LED sequencer. IT is like writing 
> "Hello Wolrd" when yo uare learning new computer language.
> I'm sorry for so many questions but you see I'm about to spend my money 
> on something  and there you are telling me that I shoudl reconsider what 
> I'm doing (TRUST ME I have nothing against it ...in fact it might be even

> a blessing before I would go bald trying to figure things out)

You need to decide at what level you want to jump in. You can get
completely packaged solutions for any problem if you want to spend enough
money. Or, you can buy the individual parts and put it together on your



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