On 7/1/07, Lawrie Griffiths <[EMAIL PROTECTED]> wrote:
> Charles has not worked on the project for many month now, so we are missing
> C and emedded programming skills.
>
> The performance of lejos NXJ is not that good compared to, for example,
> RobotC, and the LCD DMA makeover would be a big contributor to this.

Cool. I don't have my NXT handy currently, so I won't touch the NXJ
source code for now, for fear of breaking stuff, but I'll see about
porting the lcd driver I have to NXJ as soon as possible.

> - I2C sensors. Charles was the last person to work on this. I2C writes do
> not work, which stops a lot of multiplexers and such-like working with
> lejos. It also prevents callibration of I2C sensors.

Softmac I2C is nicely tricky (well, for me and my experience at
least), so I have nothing to offer on that front yet.

> - Playing sound sample files.

That should be relatively easy, using Lego's RSO format.

> - Graphics. We have some graphics support in Java, but some of it would be
> better in C.

Can you elaborate on what kind of graphics support you're thinking of?

> Another problem is that the flash (ROM) versions of lejos NXJ has some
> problems, particularly when writing to flash memory. This seems to be
> related to the AVR link. I think I now have a solution to this, but it is
> not a very satisfactory solution.

I think I can imagine the problem. Does the AVR link die while
writing? That happens on the kernel I helped develop as well, when the
system gets flooded with interrupts, enough to starve the lower
priority handler that does the link synchronization. Is it something
similar?

> Other drivers including the USB driver and Bluetooth driver need some more
> work on them.

We have an interrupt-driver USB driver that mostly works (though it
also still needs work). The Bluetooth driver is probably going to be
developed as part of  a school project next term, so we could get it
to work with lejos as well.

> It would good to write a driver for the high-speed serial comms capability
> on sensor port 4.

Are there any peripherals that take advantage of this yet? Developing
drivers is always more fun when there is something to drive on the
other end :-).

What about scheduling? Currently the scheduler is built into the VM.
Is there any point in bringing that down to the C level? Personally,
I'm planning to do this on my kernel, as the objective is to be able
to run C tasks, but I don't know how much use this would be to NXJ.

- Dave

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