Using C to program the 8051 family

... snip ...

I am assuming GNU GPL here, but there are other licenses.

It makes no difference to distributors, because in general the licenses allow charges for services. The only thing it prevents is third parties seizing the code and applying their own copyrights.

As an example, I could create a new machine, either in hardware or as a simulator, copyright/patent/whatever that, and adapt gcc to generate code for it. I get the useful software to promulgate my ideas for essentially nothing, or at least a minimum of my effort. I retain complete ownership of the machine, the right to charge whatever I wish for it, but NOT the right to hide or restrict use of my gcc mods.

Of course, should you wish, you are welcome to create a compiler for your new machine from scratch, and then charge what you wish, and hide all the details. I suspect it will be a few years before it is as accurate or flexible as gcc. Meanwhile you will have to keep your whiz-bang off the market, and the business may well go elsewhere.

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Chuck F (cbfalconer@yahoo.com) (cbfalconer@worldnet.att.net)
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GPL also restricts use in commercial products. That's not usually an issue with gcc, since the libraries are LGPL, with fewer restrictions.

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Al Balmer
Balmer Consulting
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I'd have to disagree. Geeze, the 8080 required _three_ supply voltages (+5, -5, and +12 IIRC). The Z80 only required a single 5V supply. That was a huge advance. The clock circuitry on the Z80 was also much better and didn't require a high-voltage dual-phase clock generator chip. All you needed was a single phase 5V TTL clock signal.

The Z80 interrupt model was far, far superior to Intel's crappy hack which required an external interrupt controller in the form of an 8059 (a horrible mistake which we're unfortunately still stuck with).

The Z80's dual register banks also made interrupt handling or coroutines on the Z80 much easier than on the 8080.

The Z80 had built-in refresh circuitry for dynamic RAM. With the 8080, you had to add a dynamic RAM controller chipset.

All told, the Z80 eliminated the need for two power supplies and about a half-dozen not-very-cheap support chips.

The addition of two 16-bit index registers also made for far superior code generation for high-level languages. There were

80 new opcode that included block move and block I/O instructions.

And it just plain ran a hell of a lot faster.

IOW, the Z80 completly kicked the 8080's arse. Once the Z80 came out the 8080 completely vanished from new designs. The

8085 was a very lame, late, and failed attempt at meeting the challenge of the Z80.

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Grant Edwards                   grante             Yow!  I'm RELIGIOUS!! I
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What? IANAL, but I have read the GPL. I don't remember any restriction on use in commercial poducts. Got a cite?

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Grant Edwards                   grante             Yow!  Will the third world
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Read the GPL again, the part where it talks about distribution of unmodified and modified versions.

If you modify a GPL'ed work, and distribute the binary, under ANY TERMS WHATSOEVER, you are required to grant the people who receive your binary permission to redistribute it *AND* you must provide your source code to them for not more than a nominal copying and media charge AND you must grant permission to redistribute your source code as well.

LGPL carries less "onerous" terms.

The fundamental idea is that software released under the General Public License is freely redistributable, freely modifiable, and comes with SOURCE CODE that is freely redistributable and modifiable, and it is damned well going to STAY that way.

This is interesting. I've never thought about it before, but I've done dozens of microcontroller based projects and I've never used an ICE either.

Bob

I suspect he means the need to publish source code sometimes.

Ian

Sorry I was meaning the one in the keyboard itself.

Ian

Could be, but that restriction applies equally to commercial and non-commercial uses. He specifically stated that the GPL restricts use in commercial products.

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Grant Edwards                   grante             Yow!  ... I want to perform
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But it doesn't matter if it's commercial or non-commercial.

Right. I still don't see how it's specific to commercial products.

I know. But you state it "restricts use in commercial products". To me, that means that it somehow places additional requirements on commercial products that aren't placed on non-commercial products. Apparently I misunderstood what you meant by "restricts use in commercial products".

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Grant Edwards                   grante             Yow!  I'm having a BIG
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[...]

This approach has been used effectively by Intel and Axis, especially Axis, whose whole processor business depends on GCC and Linux. For Intel, it allows them to get real world performance numbers on new processors many times faster than otherwise possible.

It is rarely not in a hardware company's interest to support open tools that support their products.

No, Grant, I don't state that. The other guy stated that. I just explained the rules.

You are correct that the rules are the same for commercial and noncommercial use. However, the noncommercial guys generally aren't impeded by those rules, since they are not trying to make a buttload of money off of it, and don't mind if someone else redistributes their work. (In fact, they usually WANT it redistributed far and wide, so they get the karma boost.) The commercial guys are usually the ones foaming at the mouth at the idea that someone else could rip them off, not understanding that they are already ripping off the original copyright holders.

the

Sorry about that. I mis-read the quote levels.

That was my understanding.

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Grant Edwards                   grante             Yow!  Do you have exactly
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Yes. IF you distribute the compiler.

If you modify it and use it without distributing the modified compiler, you can keep everything secret.

No.

[At least in the case of GCC and the GPL.]

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Debug stub and a serial port. I'm doing it right now on an H8: burn gdb stub in to flash, and away you go. Downloading is a bit slower than traditional ICE, but it works quite well.

See above.

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Grant Edwards                   grante             Yow!  Intra-mural sports
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There on no restrictions on using GPL products to create commercial software.

There ARE restrictions on _incorporating_ GPL products in commercial software. If you do so you have to make the complete source available without restriction. Note that you are still perfectly free to sell your stuff, all you have to do is find customers.

The LPGL license allows you to incorporate the product in your commercial software, without having to make any code beyond that covered by the LPGL license available. Now you can keep your secrets and still hawk your widgets.

As far as using gcc is concerned, you are no more restricted than if you used commercial compilers, in fact probably far less so.

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Chuck F (cbfalconer@yahoo.com) (cbfalconer@worldnet.att.net)
   Available for consulting/temporary embedded and systems.
     USE worldnet address!

Note that you don't have to *give* the source code away, just provide it for a reasonable distribution fee. Richard Stallman funded the early days of the GNU project from the distribution fees of his GNU compiler. I believe he was charging $100 for a magtape of the source.

But it has not stopped commercial closed source extensions to gcc being produced e.g hitech

Ian

IIRC, They claim they wrote a completely-from-scrach contains-no-GPL'd code back end that works with the gcc front/middle parts, and that the assemblage of their backend with the gcc front end isn't a "derived work". Whether that's accurate or valid is a matter of debate.

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Grant Edwards                   grante             Yow!  I don't know WHY I
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