Ethernet chit chat...

[Dave]

I have been presented with two good contenders for an ethernet solution for the QL. There might be others; I am open to suggestions and may add more to the list.

I would like there to be a polite, friendly, respectful, constructive debate about the relative merits of the two devices. Once you have expressed a view, that's enough. No need to restate it, unless you add something further. It is very important that discourse be focused entirely on solving the problem of getting ethernet onto the QL.

Please read the data sheets and form an opinion about which would perform better on a QL at 7.5MHz or a SGC system at 25 MHz. There is already a TCP stack in existence; whether you wish to use it or not is a matter for you - one of the chips is a microcontroller that has its own stack.

Here are the contenders:

Wiznet WS5300
http://www.wiznet.co.kr/UpLoad_Files/Re ... _V128E.pdf

versus
Cirrus Logic CS8900
http://www.cirrus.com/en/pubs/proDatash ... 00A_F5.pdf

If there is a clear consensus, I will assemble some functional prototype boards using the favored device, then send boards and documentation out to a limited number of people who express an interest in doing development work with them.

There would be some gentle conditions:

1. You'd join a developer mailing list and report occasionally on progress you'd made to the other three people and me. Others could join the list to provide feedback, etc. The list would allow you to self-co-ordinate your efforts within the group. I would not be the boss of you. I would not own your work. There is no schedule or deadline.
2. Anything you do, once reaching a state of development greater than "alpha", would be open source and freely distributable. A GIT repository or similar would be nice.
3. I would, upon release, host information and downloads at SinclairQL.com so people can explore the code or develop it further.

If anyone develops anything to a point that it becomes possible to add ethernet to a future board, or standalone, I would work out a way to produce them for the community. If not, you can keep the card as a curio/plaything/collectible, or send it to someone else who has shown an interest.

So, let's begin, shall we?

[tofro]

Dave,
you seem to have made your choice already - presenting us a Cirrus chip from 1997 against a WizNet first produced 2008 is not what I would exactly consider a fair game

- Cirrus no 100BT - rules it basically out
- But might fit the QL better hardware-and-signal-wise
- ISA-Bus interface in the Cirrus - Eeeeh!
- WizNet has nearly the complete stack already implemented and would off-load the QL considerably
- Drivers for WizNet waaaaay simpler to implement. Wouldn't even need to be asynchronous, as far as I can see.

Although I would see it as an academical challenge to implement drivers for the Cirrus, probability of success is much higher for the WizNet. Not sure we'd have drivers done for the Cirrus before it's finally EOL (which can be anytime soon).

Tobias

[Dave]

Both chips were recommended to me. I'm presenting them without any judgment.

They are quite different in how they work. They cost about the same to implement. Off-forum, someone has made some good arguments for the CS8900 that they might like to repeat here. Someone else for the WS5300. Both are 5v friendly and Motorola bus friendly.

I suspect WS5300 would be easier to develop for, from scratch. I also suspect there's a lot less ground-work to do for CS8900 because it is much more widespread, better supported, and there's Linux and BSD sources to look at. I'm sure that's true of both.

If there another chipset you'd like to suggest?

[RWAP]

Well - the Spectranet (for the ZX Spectrum) has been designed around the Wiznet 1500 - I do wonder whether some of that design could be used to implement something similar for the QL - see
http://spectrum.alioth.net/doc/index.php/Spectranet

[tofro]

5100, Rich.

The 5100 supports only half the amount of simultaneous sockets (4) than the 5300. That's a bit small, IMHO, for a "real" computer and a multitasking environment.
For one ftp session you need 2 sockets, for example. Having only 4 of them might be too small a limit - I think we could live with 8 that the 5300 provides (an FTP connection, 2 sockets for e-mail in the background, and maybe some sockets for the to-be implemented web browser plus some spare)

The cirrus chip hasn't got such a limit - It doesn't implement anything at all

Network creates quite a bit of background load - You need to check all the incoming packets with a matching address and follow quite a bit of what's happening on the wire in order to properly communicate. For the QL, I think there's only two ways to do that reasonably (pretty much the same applies to USB, in my opinion, BTW):

Either you use an all-in-one chip like the WizNet that already has an MCU built in or you use a dumb chip like the Cirrus or (more common chip, your proposal, Dave:) RTL 8xxx, together with an external controller like an AVR and some dual-ported memory. A dumb chip driven directly by the QL CPU requires too much background load, IMHO and might significantly slow down standard QLs in high-traffic environments. The second option ("own MCU") has the advantage that you could think about moving more peripherals (like future USB) handling than just network to the co-MCU and the disadvantage that you have to write two drivers (one on the MCU, low-level and one on the QL, high-level) and a coprocessor interface.

All put together, I think the Wiznet is a fine choice. The MCU driver is already there and QL driver development should be pretty straightforward. One thing that must be kept in mind is that the DPM must be 'protected' from the QL OS to be regarded as normal memory during the start-up phase.

Regards,
Tobias

[Derek_Stewart]

Hi,

After a quick read of the 2 documents.

The Cirrus Logic CS8900A, interfaces direct to the ISA bus and looks to use DMA, there is no QL devices that use ISA other than the Q40/60. DMA as far as I know is not used on a QL operating system. Which maybe easy to implement, but I think the WizNet solution looks the best to me and is more up to date.

The 500Mbs on the direct connection would make the QL Networking so fast, due to the size of the data files being transmitted.

In the past I used SerNET between, QXL, QPC2, Q60, Atari ST-QL which networked faster the QL Net, but it needed a custom serial port lead, which I made very easily.

Derek

[XorA]

Just before people lose the plot, you can do raw ethernet with the 5300 as well. There is a linux driver operating it in this mode.

This means that there is the option to run in hosted TCP/IP mode on slow machines and swap to raw ethernet on fast machines.

G

[Peter]

I suggest the CP2200. It is the easiest to solder, least pins, smallest, simple connection to the QL bus. More importantly, it is already used on the Q68.

100 Mbit/s is overkill for anything less than a 68040, even if the TCP/IP stack is offloaded to an external chip.

https://www.silabs.com/Support%20Docume ... CP2200.pdf

[tofro]

100 Mbit/s is overkill for anything less than a 68040, even if the TCP/IP stack is offloaded to an external chip.

Agreed - But there is networking equipment out there that won't fall back to 10Mbit/s. Not sure how common that is, however. 10Mbit is basically a dying technology.

Tobias

[XorA]

Agreed - But there is networking equipment out there that won't fall back to 10Mbit/s. Not sure how common that is, however. 10Mbit is basically a dying technology.

Tobias

A lot of "consumer" routers went 1000/100 and just dropped 10 support in my experience.

G