[fpc-devel] Circular references and forward declarations

[Marco van de Voort]

In our previous episode, Michael Schnell said:
> > But I still use the PIC18F60j60 part since there is no
> > 16-bit integrated ethernet part, and as spare replacement for legacy parts.
> 
> This fried uses the (quite new) Microchip Ethernet MAC/PHY chip
> (including frame buffers, doing 100MBit) that can be connected to the
> PIC as an SPI slave (just three or four wires). Microsoft provides
> appropriate software for this setup. He's going to give me one of his
> board very soon. I'm looking forward to playing with that.

Yes. I bought the pictail kit for that part, and it is lying right beside
me. Trouble is that the print we have now (externally fabricated) don't
connect the INT pin needed for SPI frame mode to a connector, so it'll have
to wait a generation. Luckily we didn't buy a large batch of prints.

But it is also a bit that the whole point of the controller is being
realtime. THe ethernet stuff till now is on systems that only have to react
to 1ms magnitude events, while the 16-bitters are more like pseudo realtime
into the 10us magnitude.

External (microchip stack) software can detract from this, and will need a
lot of testing.

An extra reason is that the pic18 10-mbit stuff doesn't work very well
connected to gigabit switches.

> > The PIC32 look interesting, but there is no motorcontrol (quadrature
> > decoder) in that family yet, something that I require.
> 
> What about using a slave-PIC coupled by SPI (this is what my friend does
> all the time).

That is more like what I'm planning. It will depend how good the frame-spi
works. (IOW if it doesn't increase latency)

> As the PIC32 is a MIPS architecture, it could benefit from the MIPS port
> of FPC that quite recently was discussed here.

Not for my (work) purposes, though I'd certainly play with it. While I would
welcome a more forgiving syntax than C (with its == vs = problems), the avg
program is small (1000 line magnitude, of which 700 lines are the same
everywhere). It is not worth abondoning the supported compiler for.
 
I rather use FPC to substitute some of my 100000-200000 line programs on the
delphi side.