[Info] SRQ nibbling is broken with any xum1541 devices but the zoomfloppy

[Spiro Trikaliotis]

Hello,

this is just a general note: Currently, the SRQ nibbling works only with
the ZoomFloppy! Most probably, for every other variant, including PRO
MICRO and PRO MICRO with 7406, it is broken and will not work.

The code had problems which were fixed by Nate for the ZF in commit
fa41220489d3.

I tried to port it over to the PRO MICRO variants in commit 57bb6726e,
but I did not do it correctly. So, it is broken currently.

The PROMICRO is even so much broken that the PROMICRO does not work
afterwards. Any "cbmctrl detect" or "cbmctrl status 8" will not get any
answer. To make it work again, one has to power off the drive as well as
the PROMICRO board. Powering off only one of them is NOT enough!

I fixed the lockup problem of the PROMICRO with commit 8799fb183.
However, the general problem with SRQ nibbling not working for both
PROMICO variants is not fixed yet!

Regards,
Spiro.

--
Spiro R. Trikaliotis
https://spiro.trikaliotis.net/

[Nate Lawson]

I’ll look into this.

-Nate

> On Nov 5, 2020, at 11:53 AM, Spiro Trikaliotis <an-zoomfl...@spiro.trikaliotis.net> wrote:
>
> Hello,

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[Spiro Trikaliotis]

Hello Nate,

* On Thu, Nov 05, 2020 at 01:52:39PM -0800 Nate Lawson wrote:
> I’ll look into this.

thank you.

I just uploaded a new version for the PROMICRO (non-7406) in commit
540f099313. Here, the loop of the iec_srq_write() function should count
exactly the same clocks as the one for the ZF, if I did not count wrong
in any way.

I created the assembler listings by adding -Wa,-ahl to CFLAGS in the
xum1541/ directory.


I did not have a look into the PROMICRO_7406 yet, I want to have one
working before working on the other. ;)

[Spiro Trikaliotis]

Hello Nate,

* On Thu, Nov 05, 2020 at 11:13:05PM +0100 I wrote:
> Hello Nate,
>
> * On Thu, Nov 05, 2020 at 01:52:39PM -0800 Nate Lawson wrote:
> > I’ll look into this.
>
> thank you.

It works for the PROMICRO now with commit f6a69621879dee. Martin looked
into out and found that the ZF implementation preserves the ATN line
(because ATN is on another port), while the PROMICRO implementation
unsets it (i.e., it goes to 5V). So, the PROMICRO breaks the protocol.

The implementation in the fix above has the same cycle count in the
inner loop as the ZF implementation. But, it needs some more cycles for
set up before the loop. From my understanding, this setup is not as
critical as is the loop, is it?

> I did not have a look into the PROMICRO_7406 yet, I want to have one
> working before working on the other. ;)

I will have to do that now.

[Spiro Trikaliotis]

* On Sat, Nov 07, 2020 at 05:39:56PM +0100 I wrote:

> > I did not have a look into the PROMICRO_7406 yet, I want to have one
> > working before working on the other. ;)
>
> I will have to do that now.

Fixed with commit b6672849.

I'll do some more extensive tests. If everything is ok, I will generate
a v09 firmware for both PROMICRO boards.

[rittwage]

Hi Nate,

Is this why the prototype built on Bumble-B that you sent me never worked with SRQ? 

It gets a USB error right after the drive code loads, as if it never comes online.

-Pete

[Spiro Trikaliotis]

Hello Pete,

* On Sat, Nov 07, 2020 at 10:40:15AM -0800 rittwage wrote:

> Is this why the prototype built on Bumble-B that you sent me never worked with
> SRQ?

How old is the firmware?

I ask because the implementation on the Bumble-B is the same as the
ZoomFloppy. However, with the older implementation, (v07 and older),
there is a much higher chance that it will not work.

> It gets a USB error right after the drive code loads, as if it never comes
> online.

This looks exactly like the problem I had with the PROMICRO.

Shall I create a current Bumble-B firmware and send it to you?

[Nate Lawson]

I thought I tested this in v7 with BUMBLE-B but it’s been a very long time.

The new implementation should be used everywhere (modulo board/CPU pin layout changes).

-Nate

> On Nov 7, 2020, at 1:34 PM, Spiro Trikaliotis <an-zoomfl...@spiro.trikaliotis.net> wrote:
>
> Hello Pete,

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[rittwage]

Sure, yes- please. I tried it pretty recently with what I found online, but it could have been broken firmware.

-Pete