Re: Interested in USB for TURBOchannel (slhci at tc)?

On 2 April 2016 at 19:24, Felix Deichmann <[email protected]> wrote:

> Hi,
>
> tinkering with a Lattice CPLD break-out board and a Waveshape SL811HS USB
> board showed success: I was able to interface the SL811HS and TURBOchannel
> of my DEC 3000/400. Code for "slhci at tc" was easy, as the slhci driver
> seems mature (and portable) already.
> The CPLD features a TC interface up to 25 MHz, is capable of I/O
> transactions and interrupts, and even contains a basic option ROM as
> required by TC systems' firmware.
> It is a horribly "flying" lab setup with single wires between all the
> connectors at the moment (hardly stable of course, but sometimes :)), but I
> plan to design a "real" TC option module with custom PCB and even bulkhead
> for myself (and others if interested) which will solve all stability
> problems I hope.
>
> Do not expect it to be fast, SL811HS is a USB 1.1 controller (12 Mbit/s)
> and its 8-bit interface is sub-optimal (and errata-prone). I calculated
> SL811HS peak data rate over an optimal (back-to-back) TURBOchannel to be
> ~1.25 MB/s for 12.5 MHz TC systems, and ~2.08 MB/s for 25 MHz systems.
> Actual devices on the bus will show slower results of course.
>
> Is anyone else interested in such a TC-USB option? I could kick-off a
> hobbyist maker project of professionally made modules (you would get the
> assembled thing with parts soldered to a PCB, CPLD programmed and bulkhead
> mounted) then. Costs depend on amount ordered of course, but even for
> prototype/smallest volume I see it far below USD $100. I will not earn a
> single cent. Otherwise I will build manually for myself only.
> So please excuse cross-posting to the three TC-capable platforms (pmax,
> alpha, vax). It's a NetBSD special right now :)
>

Awesome :)
I would definitely buy at least two at under $100 each, possibly more. As a
non NetBSD aside, I suspect if you can get the right VMS guy interested in
writing a driver for the VMS/VAX then you might suddenly find another happy
(if not huge :) market...


More info is and will be available here (doc, pics, code, ...):
> http://www.flxd.de/tc-usb/
>
> And the alpha port seems to have really broken bus functions for widths <=
> 4 (dense vs. sparse TC space etc.). I will also come up with a patch for
> that soon.
>
>