[sebhc] Good news, bad news -- Robin succeeds; Message too long (>20000 chars)

Jack Rubin jack.rubin at ameritech.net
Mon Mar 27 07:08:23 CST 2006

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-----Original Message-----
From: sebhc-bounces at sebhc.org [mailto:sebhc-bounces at sebhc.org] 
Sent: Monday, March 27, 2006 3:15 AM
To: sebhc-approval at sebhc.org
Subject: BOUNCE sebhc at sebhc.org: Message too long (>20000 chars) 


Hi Dwight

Thanks (again) for your valuable assistance! BTW I hope you are feeling
better now.

Unfortunately due to my job I don't get much free time to spend on my
hobby, but this weekend I was able to finally spend a couple of hours in
my workshop and got to the bottom of the serial problem I was having! At
last I have your disk transfer program working fine now!

The cause of the lack of serial comms was actually that the 8250 itself
was faulty. Talk about bad luck; I had originally discounted the serial
card having a hardware fault because I tried swapped serial cards
between my two H89s and this had not fixed the fault. As it turns out,
BOTH the serial cards had duff 8250s in the LP port circuit !

In the end, I swapped an 8250 from one of the other ports on the card to
the LP section and your loader started to work fine. I can't imagine why
the 8250s on the LP port on both machines should have both suffered the
same fate; the line drivers associated with the LP port on both serial
cards are absolutely fine. I'd have thought that if someone has
mis-connected the LP port on both machines, or subjected it to static
discharge the line drivers would have been the first to go!

There was one other problem that's worth mentioning for those who also
want to use your H89TRANS. On my pure DOS machine I have Windows 3.1
installed and as is usual with Win3.1 installations, I also have
SmartDrive installed. When I initially got your loader program
communicating I found that at some random point during the transfer of
data between the H89 and the DOS PC, the communication would suddenly
stop. However, when using the floppy drive (on the DOS PC) as the source
or destination, the problem did not occur. I found that not loading
SMARTDRV.SYS on the DOS PC fixed this and allowed the data transfer to
complete successfully.

I've now saved the loader on the H89 to a new disk successfully so I
don't have to re-enter the loader into the H89 each time. Also have
successfully 'imaged' one of my original disks and have written it back
to another (blank but INITed) disk with no problems.

I've only two disks that came with the machines, both are HDOS with
INIT, SYSGEN and one has BASIC, so I'm looking forward to playing with
some of the images that are now in the archive.

I also got myself a Z80 assembler (freeware) from Programmer's Heaven
which works fine (I converted your source listing for the loader from
8080 to Z80 opcodes successfully and it generates an exact (hex) listing
to your octal listing for your 42 byte loader which was reassuring!).

BTW, another approach I thought about trying was to use a different
serial port in your loader program by changing the base address (0xE0)
but I can't find a map of I/O addresses for devices in the H89, is there
a definitive list somewhere?

Also, can you (or anyone) explain the significance of the volume number
to me? Your program allows you to set (override) a volume number or take
it from a disk image. I assume that this is the 'unique volume number'
that you are asked to input (from 1 - 255) when INITialising a disk.
What is the importance of this (i.e. will setting the wrong volume
number when creating an actual disk mean that the disk won't work?).

Thanks again for your help!

----- Original Message ----- 
From: "Dwight Elvey" <dwight.elvey at amd.com>
To: <sebhc at sebhc.org>
Sent: Friday, March 24, 2006 1:56 AM
Subject: Re: [sebhc] Fw: Re-creating actual floppies from archive

> Hi Robin
>  When I'm debugging serial, I often change things to have a simple 
> loopback. I then set the serial port of my PC to a slow baud rate ( 
> usually 300 buad ). This way I can actually see the blinking lights of

> the serial light test box.  I believe, a few simple modifications to 
> my ~50 bytes could give you this at the H89 level so that you could 
> test out the H89's LP port. If you have an oscilloscope or logic 
> probe, you can watch the signals at the chips on the serial board as 
> well.  Here is some patches that should put the H89 into simple loop
> back running at 300 buad. First enter all the bytes for the
> BOOTSTRP.OCL as you normally do. Next, make the following
> changes:
> at 043 013   enter  200, 303, 053, 043
> at 043 035   enter  060, 043
> at 043 050   enter  323, 340, 351, 076, 001, 303, 017, 043
>  I hope the listing I have is the same because I'm not
> on the machine that has the most current listing. Right
> after you enter the first values location 043 051 should
> be 351 ( E9h ). After the patch it should be moved to 043 052.  Also, 
> rather than step dwon through memory, the value recieved by the serial

> port is placed at 043 060. This is useful to see which function is 
> working or not working, RX or TX. You can send a bunch of 'A's and 
> look for that in that location.
>  You need to run a terminal program with 300 baud and 8 bits.
>  I hope this helps you debug your problem.
> Dwight
> >From: "Robin England" <robin.england at dial.pipex.com>
> >
> >Hi Dwight
> >
> >I replied to your email off-list (please see below) but I think you 
> >may
> >have received it due to spam filter?
> >
> >Apologies if you've already seen it and haven't had time to reply. 
> >Also I was wondering what 8080 assembler you recommend for writing 
> >code on the H89? I think I need to write
> >to test the LP port!
> >
> >Regards
> >Robin
> >
> >----- Original Message -----
> >From: "Robin England" <robin.england at dial.pipex.com>
> >To: "Dwight Elvey" <***********>
> >Sent: Monday, March 20, 2006 10:34 PM
> >Subject: Re: Re-creating actual floppies from archive
> >
> >
> >> Hi Dwight
> >>
> >> Thanks for your help so far. Sorry to hear about your video 
> >> problem;
> >funnily
> >> enough the same happened to one of my H/Z89s the other day when the

> >> 53v regulator transistor decided to go short circuit for no reason!
> >>
> >> No, unfortunately I've still not got to the bottom of the problem 
> >> with
> >> loader. Quite simply, the H89 does not appear to be dealing with 
> >> the
> >serial
> >> input from the PC. The area of memory that should be overwritten by

> >> the loader (starting at 046-133) remains unchanged when I go back &

> >> check


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