Announcing availability of a QLNET driver for the Q68 (ND-Q68)

[martyn_hill]

Hi Pr0f

The propeller has several timers on board plus access to the cpu clock timer. Also useful is a wait on I/O port which could be used to trap for the start of a sequence on the network I believe the Inteface 1 used something similar. So with the timing routines it should be possible to read the QL network quite accurately. I could dedicate a cog to just reading the network and stuffing a buffer in the shared memory for other cogs to process.

I like it!

Yes, the Interface-1 ULA can be set to activate the 'HALT' line to the Spectrum's Z80 until it sees the next START bit of the next byte-frame. Its a completely blocking activity and only initiated once something like a SCOUT has been seen on the wire... (BTW - there's a bug I found in the Interface-1 ROM that messes with packet reception in certain circumstances - once I get around to replacing the 2364 mask-ROM with an EPROM on my Int-1, I'll test the correction.)

It wouldn't have worked well in the ULA of a multi-tasking machine like the QL, which leverages instead the IOSS Retry mechanism (very) successfully to 'catch' the next packet SCOUT and then defers to software time-out loops waiting for each successive START bit.

If a buffer could be employed and a dedicated, 'NET protocol-aware' Cog programmed to do the business in the background, this would be a very neat solution - much like the design of my (almost complete) QLUB adapter (QLan to USB-Bridge).

Watching with interest...

[FrancoisLanciault]

A very good news!

The compatibility with the Interface 1 is a big plus for me.

About the electronic add-on needed, it is not clear to me what the red lines in the PDF means i.e. what needs to be removed from the original schematic. But I am in no rush and I am sure everything will be clarify soon. I need to finish printing my Q68 laptop casing anyway.

Franois

[afx]

On this Father's Day (in the UK, anyway), I am pleased to announce the availability of driver software that allows you to finally network the Q68 with other QL-compatible machines via the standard QLNET ports ...

Martyn … great job!!

Furthermore, given the Q68's reliable, high-speed SERial port, Peter has also already had some success running ND-Q68 alongside the brilliant SERNET driver, allowing the Q68 to act as a 'bridge' between those nodes with real QLNET ports and other machines such as the Q40/Q60 and emulated QLs running at up to 115,200 Baud.

Cool!

If you do decide to make this mod yourself, do take care not to brick your lovely Q68 - it's very tight in there and remember that it runs at 3.3v (hence the absolute need for the diode)...

About the electronic add-on needed, it is not clear to me what the red lines in the PDF means i.e. what needs to be removed from the original schematic ....

Unfortunately I have few skills to make that mod in the Q68. (I have panic to manipulate my Q68, and I don't understand the electronic schema). Is there any guide to facilitate that mod? (For example some photos, videos, ...).

[martyn_hill]

Good evening afx and Francois

If you are hesitant to make the HW mod yourselves, I believe that Derek Stewart from whom you purchased your Q68 HW is currently researching some viable solutions and plans to offer a modification service in due course.

I will be posting some guidance plus photos from my own setup in due course, but that's just one approach and not as good as Derek would devise!

[Dave]

I'm a bit concerned by the mod shown in the pdf. Its behavior is correct when the Q68 is powered, but if there is traffic on QLNET when the Q68 is unpowered, signal will still be passed to the FPGA regardless, plus try to power the Q68 through the diode. This would be problematic. Am I misreading it?

My solution would be to use a pair of BSS138 transistors to create a level shifter that would be high impedence if unpowered.

What do you think?

[martyn_hill]

Sounds good to me, Dave. But then, I'm just the SW guy

[Derek_Stewart]

About the electronic add-on needed, it is not clear to me what the red lines in the PDF means i.e. what needs to be removed from the original schematic. But I am in no rush and I am sure everything will be clarify soon. I need to finish printing my Q68 laptop casing anyway.

Hi Francois,

The digram is taken from the QL schematic and a diode added to clamp the voltage, different valued resistors.

I am not at a computer, just Android tablet, so I will post a clearer diagram. Probably tomorrow...

[afx]

If you are hesitant to make the HW mod yourselves, I believe that Derek Stewart from whom you purchased your Q68 HW is currently researching some viable solutions and plans to offer a modification service in due course.
I will be posting some guidance plus photos from my own setup in due course, but that's just one approach and not as good as Derek would devise!

Thank you very much!

[Peter]

About the electronic add-on needed, it is not clear to me what the red lines in the PDF means i.e. what needs to be removed from the original schematic.

All three resistors with direct connection to the transistor, and the transistor itself, are removed.
The idea was to show the difference between Q68 and QL circuitry. Sorry if that was misleading.

[janbredenbeek]

Thanks Martyn! Unfortunately I haven't been able to test it up to now but it will be a nice project for my upcoming vacation .

This driver could also be incorporated into the Q68 Minerva image (in the extrarom space), as well as a serial driver.

One idea for the hardware geeks: why not use the sound output jack for QLnet or perhaps make it switchable using a jumper?

Jan.