Re: [N8VEM: 8263] Re: N8VEM respin VDU PCBs have arrived!

[flatlander <tast...@gmail.com>]

Hi All,

Thanks for the information - I'll have a go, just as soon as a get a
free weekend!

D. :o)



On Nov 8, 12:52 am, "Bob Devries" <devri...@gmail.com> wrote:
> The CRTC initialisation table used on my SECAD AS-68K if driving a CGA
> monitor, is this:
>
> 113, 80, 90, 10, 31, 6, 25, 28, 2, 7, 6, 7, 0, 0, 0
>
> Hope that helps someone.
>
> Regards, Bob Devries
> Dalby, QLD, Australia
>
> ----- Original Message -----
> From: "Andrew Lynch" <lyn...@yahoo.com>
> To: <n8...@googlegroups.com>
> Sent: Monday, November 08, 2010 9:52 AM
> Subject: RE: [Bulk] [N8VEM: 8263] Re: N8VEM respin VDU PCBs have arrived!
>
> Hi!  The VDU is not explicitly tied to NTSC or PAL.  It will not require
> hardware changes to support PAL although the SY6545 CRTC register
> initialization sequence will have to be changed.
>
> There is a worksheet in the MC6845 datasheet that shows how to do the
> calculations but it still takes plenty of time and effort to do it.  However
> it can be done and if you do get it to work please post the code on the
> N8VEM wiki.
>
> There may be builders in PAL countries with VDUs who may be ready to help
> you.  Dan and I worked on the NTSC initialization sequence and it works for
> a variety of settings so I imagine you would see something similar with PAL.
> However, some settings were definitely better than others.  You just have to
> tweak it repeatedly until you get what you want.  A lot of patience helps!
>
> You can also change the dot clock from 16 MHz to something more compatible
> with your monitor.  That will require a unique initialization sequence too.
> Please post your results and maybe we can help you.  I found an oscilloscope
> to be very helpful.  Measure the HSYNC and VSYNC while changing the
> parameters.
>
> Thanks and have a nice day!
>
> Andrew Lynch
>
> > -----Original Message-----
> > From: n8...@googlegroups.com [mailto:n8...@googlegroups.com] On Behalf Of
> > flatlander
> > Sent: Sunday, November 07, 2010 1:51 PM
> > To: N8VEM
> > Subject: [Bulk] [N8VEM: 8261] Re: N8VEM respin VDU PCBs have arrived!
>
> > Am I right in thinking that it will only require register changes to
> > make the VDU board work with a PAL display, or will it also require
> > hardware modifications?
>
> > Thanks,
>
> > D. :o)
>
> > On Nov 6, 5:43 pm, "Andrew Lynch" <lyn...@yahoo.com> wrote:
> > > Hi! Good news! The N8VEM ECB respin VDU PCBs have arrived! They are
> > > functionally the same as the previous VDU boards. They underwent a PCB
> > > respin which dramatically cleaned up the trace routing. Also I replaced
> > the
> > > 4x2 keyboard and mouse connectors with somewhat easier to use and find
> > 5x2
> > > connectors.
>
> > > Please contact me if you would like a VDU PCB. Thanks and have a nice
> > day!
>
> > > Andrew Lynch
>
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