AVR vs. 68HC11/68HC12

I am interested in building haunted house animatronics. I am trying to
settle on a microcontroller family to use, because I know I will be
reluctant to switch once I get started.
By reading various robotics books and microcontroller comparisons on the
Internet, I have narrowed down my choice of microcontroller families to
either: (1) the AVR family, or (2) the 68HC11/68HC12 family. (The PIC
family seems a little too low-level, and the 8051 chips seem a bit quirky.)
I am having trouble deciding between the AVR and the 68HC11/12 lines.
I'm wondering if there are any former 68HC11/12 users out there who switched
to AVR, who could tell me why they switched. Or vice versa. I have read
several places that there seems to be a groundswell of people switching to
AVR chips. But David Cook, whose robotics books I tremendously admire,
strongly supports the 68HC11/12 family.
The microcontroller attributes that are important to me are: (1) low cost
(preferably under US$5 chip in single quantities); (2) large range of
processors in the family, for both lower-end and higher-end applications;
(3) strong supporting community offering aftermarket products, programmer
boards, example software, etc.; (4) lots of I/O lines (12 or more would be
nice); (5) on-board PWM capability to control servos; (6) on-board UART and
SPI features; (7) A-to-D converter; (8) a built-in clock would be nice; and
(9) 1K of RAM and 4K of some sort of static program storage.
Using Digi-Key's web site to look up comparative pricing, it looks like an
AVR microcontroller with the above types of capabilities runs about $4 in
single quantities, whereas a 68HC11/68HC12 with similar capabilities runs
about $17 in single quantities. That is a big price difference. I think I
must be misunderstanding something. Low cost is not an overwhelming factor,
but it's fairly important to me, because some of my projects might use a lot
of embedded microcontrollers.
I know I'm kind of opening a can of worms here, since everyone has their own
reasons for liking a particular microcontroller family. I wouldn't leave
such an open-ended question here except that I've been having a devil of a
time figuring this out, even after many Google searches and reading many web
sites. Please, if anyone has any thoughts on AVR vs. 68HC11/12, I'd very
much appreciate hearing them. Many thanks for your time!
-- Randy Forgaard
Reply to
Randy Forgaard
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My original message on this newsgroup said that I would like to do haunted house animatronics, that I was trying to choose between the HC11/HC12 and the AVR families to be my main microcontroller going forward, and asking if anyone here had experience with both microcontroller families who could tell me why they switched to the other. When I didn't get any responses here (no big deal, I know that most people have only used one microcontroller family), I posted my same message on AVRfreaks.net. Since that is an AVR forum, I was getting an admittedly very biased sample. But I got several replies from various people who previously used HC11/HC12s for many years, and who have switched to AVRs, explaining why they switched. I found the responses interesting. I thought I would post a summary of the responses here, in case it is useful. I don't know of an equivalent HC11/HC12 forum where I could pose the same question, to get the other point of view, but if I f1. The AVR family is just as powerful as the HC11/HC12 family, if not more so.
2. The AVR family is significantly cheaper than comparable HC11/HC12 microcontrollers.
3. There is a wider range of AVR microcontrollers than HC11/HC12s, at a large range of price points and features, while still preserving the same core instruction set.
4. The AVR family runs much faster than the HC11/HC12 family.
5. The higher-end AVRs have more program storage space than the higher-end HC11/HC12s
6. Motorola/Freescale has inconvenienced their installed customer base by dropping the HC11, requiring customers to redesign their products to use the HC12 instead, which has a different pinout and other incompatibilities with the HC11.
7. AVR is the new whiz kid, the up-and-comer, whereas the the HC11/HC12 is older architecture.
8. AVRs seem to have better support than the HC11/12 line, especially from the company, but also from the user community.
-- Randy Forgaard Haunting enthusiast
Reply to
Randy Forgaard
Comparing a 8-bit AVR to a 16-bit HC12 is like comparing an 8088 to a 80286, and saying the former is more powerful. It's fantastically misleading.
Not significantly cheaper. Low end, yes, cheaper. (But then you can get cheaper HC908's in the next line down that out perform the low end AVR.) Mid range up, no, comparable.
I have to say this is propaganda. Both are very wide lines. You're comparing one line from AVR and two from Freescale/Mot. Yet the HC12 is based on HC11 at the source level. Change the statement to the same source code instruction set, and HC11/HC12 wins. Broaden the scope to similar architecture, HC908/HC11/HC12 wins bigger yet. But for exactly the same core instruction set, and only considering one line, that is AVR's marketing promotional material claimsmanship.
If both companies added their ARM lines, then neither could make the claim, and they'd both come out neck and neck again.
AVR runs neck and neck with HC11's for same clock. AVR's run a faster clock. HC12's are 16 bits and comparable clocks. HC12 is probably the fastest of all.
Incorrect. I think they are both at 128K. However, the new HC12's have huge program spaces, 256K and 512K, coming. I don't know what AVR has coming.
Partly true, and significantly false. The oldest HC11's (A8's) have been dropped. The best HC11's (E9's) are still available with no sign of being discontinued. No one is forced to HC12's. However, the new developments are all in the HC12's and the HC11's are not being renewed, expanded memory, sped up, etc.
Definitely not. HC11 was whiz kid in 1986. Around 1995 AVR became the new wiz kid, specifically because of the flash and bootloading. The HC12 dates to about 1998. Now both lines have advanced since then, but HC12 has the latest in large memories, etc.
Think this is true, but just barely.
To me, these comments have missed the essential point. As far as I'm concerned there's two reasons AVR's grew and were popular, over HC11/HC12's. They got Flash right. The got the built in bootloader right. HC12's came out, and they had 100 times programmable Flash. Although we'd been one of the very first HC11 support companies, we didn't promote the HC12's for this very reason. We made a few boards and we didn't even get the 100 times programming before the Flash failed. If you are doing an interactive development, that is just out of the question bad. We lost market share for not hoping on HC12, and we lost market share for not switching to AVR. We have AVR now. We also have HC12's now that their Flash is better, but it is still disappointing compared to AVRs. If you don't have many-time reprogrammable Flash, you don't want people reloading your Flash frequently, which the AVR can do, and is not emphasized at all in the Mot line. JTAG is the preferred loading method of HC12.
OTOH, the DSP56F80x family's flash, from a different division of Mot, is fantastic, we've reloaded thousands of times (first release life expectancy were listed at 100,000 times, and have been down graded to 10,000 times now) but we just never see any failures. So we bid our time releasing new products until we had something we thought was generationally better than AVR/HC12 type processors. Now the new ARM's fall in that category. Why would you choose a 10 year old product line to base your future on? If I could choose only one core processor to use, I'd choose ARM, and be able to get micros from a vast number of manufactures. Both Atmel and Mot have ARM processors now, and so does Philips and Samsung and...
Reply to
Randy M. Dumse
How much does it cost for a C compiler/ IDE for HC12s, though, compared to AVR (zilch)? One of my engineering teachers said that you need a different compiler for the HC12, and it is not cheap (for the enthusiast or TAFE colleges).
Any information on this aspect?
Reply to
It doesn't. Download the GNU HC6811 and HC6812 compiler and libraries. For an IDE lookup BloodShed's DEV C/C++ IDE. There are more of both.
I've heard that there's open source compilers for the AVRs also.
Reply to
Yes, that's where the throw goes to the AVR and
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for wide support of the processor, which was the final question I answered.
Currently, I'm pretty livid with Code Warrior. We've struggled with CW a great deal for our 56F80x projects. We've been able to work around them. But just now, we are finding things deeply buried in their libraries, that got by us, that absolutely offend us as not being in the slightest professional. I don't think I'll ever see a CW product as "worth the money" again.
But there are commercial C compilers for HC12's. I'm not up on them.
While I haven't used it personally, looks like there's GCC for HC11/HC12.
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Reply to
Randy M. Dumse
I'll let my teacher know
Reply to
April the 25th
Why not start with arm7 chip ? 16/32 bit faster than both HC11/12 and avr Available in larger ram and flash Free compilers and ide (gcc and eclipse)
Not as easy as avr or pic to start with but not that hard.
One thing is avr seems to have a lot better support for non-windows operating systems.
I started with pic, since have used avr , 8051 , m32 and arm7.
Pick the chip that has lots of designs to get started with and ones you want to build. Build a few simple designs, then modify them to things you want to build. Learn it. Get some chips , plus a board. You will learn more electronics using a breadboard and veroboard than you would using a premade board. using a premade board.
If using avr atmega32 is a good one For cheap avr , pic, and 8051 boards
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Avr butter flys are also very good to get started with. A butterfly + base board is easy to use for lots of stuff.
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For animatronics look at motor control , servo motors , optocouplers , hbridges etc
I wouldn't worry too much what chip you start with, just get going
For the butterfly
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code for avrgcc
Reply to
Alex Gibson
Dale, we sell low cost ($200) compiler for both AVR and HCS12. Our demo is fully functional for 45 days. A number of schools use our ICC12 for the school courses and also a number of books have been written using ICC12 for examples.
Email me if you have further questions.
Reply to
Richard M.

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