Re: [myhdl-list] MyHDL and synthesize to non HDL

[Jan D. <ja...@ja...>]

Joachim König-Baltes wrote:
> I've used MyHDL to model the 1-wire protocol from dallas
> between a master and a slave, and it was really easy to
> do so although I was a bit skeptical concerning the
> restrictions of standard generators.
> 
> I was even able to write it as an OO model based on classes.
> 
> As the protocol is rather stable now I'd like to use the
> model for synthesizing it, but not into hardware but:
> 
> I'd like to use AVR microcontrollers for doing some home automation
> with the 1-wire protocol for the communication between them
> (because it's simple and electrically uncritical over "long"
> distances). I'd like to map it onto different resources inside
> the AVRs depending on their capabilities (UART, port, USI) and
> have written models for these resources.
> 
> The AVRs can be programmed in C rather easily.
> 
> Now to my question:
> 
> Is MyHDL suited to synthesize C from the python code?
> 
> My idea would be as follows: A class instance could model a particular
> AVR microcontroller and I could assign ports or an UART to be
> used for 1-wire communication (and other purposes). I would then
> like to simulate the combination of instances connected to form
> a 1-wire network and then synthesize one of the instances to C in
> order to generate the program for the flash of the AVR.

I've looked at some AVR examples very briefly.

As I understand it, you can use C to program the AVR
architecture by referring to symbols representing registers
and hardware primitives. So it's a "low-level" kind of C code
in the sense that you couldn't use it for anything else than
to program AVR controllers. We are therefore not really
talking about MyHDL to C, but MyHDL to AVR.

> Is this somehow possible (I'm willing to dig deep into MyHDL). If
> not, what else can I do with the model? If I still have to hand-code
> the AVR in C, how can I at least have some advantage of MyHDL in
> relation to the C-program?

Integrating generic C code based on a functional interface
in Python code would be trivial. But again, this doesn't seem
our case here. The hardware interface is embedded in the AVR C
code in the way the register symbols are set up and used.

In short, while I don't exclude that meaningful things could be
done, I don't immediately see what and how (and in a reasonable
development time).

Jan

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Jan Decaluwe - Resources bvba - http://www.jandecaluwe.com
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