> Of course maybe the "correct" way of doing this is to ditch the > OS ROMs altogether and roll your own bespoke app which talks to > the bare hardware and lives in the normal ROM sockets - any > attached disks are then purely for entertainment data.
this is a good idea
only slight problem, just slightly out of my scope ;@)
And I cannot use the Ogg player from Peter Nulls as I am assuming it needs RISC OS :@P
In article <hYyEh.27312$OK6.19...@newsfe4-win.ntli.net>, Michael Emerton <MichaelREmer...@hotmail.com> wrote:
> <snip> > > Of course maybe the "correct" way of doing this is to ditch the > > OS ROMs altogether and roll your own bespoke app which talks to > > the bare hardware and lives in the normal ROM sockets - any > > attached disks are then purely for entertainment data.
> this is a good idea > only slight problem, just slightly out of my scope ;@) > And I cannot use the Ogg player from Peter Nulls as I am assuming it > needs RISC OS :@P
Probably ported from source code that existed in Linux. Have you checked? It could "relatively easy" to recompile under whatever you require.
In message <b0e1a5b94e.b...@Iyonix.woosh.co.nz> b...@woosh.co.nz (Ron) wrote:
> The RiscPC connector is: Red +5v > Red +5v > Black 0v > Black 0v > Yellow +12v > Blue -12v
> There are standard colours on most ATX psu's but it would pay to check > at least the +12v and -12v lines. From memory, the purple wire somewhere > near the center of the atx connector gets grounded to turn the psu on.
Just to correct myself, it is the green wire (not purple) on the ATX mainboard connector that is the soft-power line. It is the 4th from one end and it needs to be grounded to get power from the ATX psu. Cheers -Ron
Jules <julesrichardso...@remove.this.yahoo.co.uk> wrote: > Hmm. For a car system with an LCD (presumably run via a serial or parallel > port?) as the main display, there's no *need* for normal graphical video > output either. Whether the system would power up and initialise without > any video is another matter.
IIRC the +12V is required for the analogue video output. So it'll work quite happily with no +12V, it's just like nothing is connected to the monitor port. Also you can switch the VIDC into digital out (to the Genlock header) and it won't need +12V - you can then drive a laptop screen LCD from that.
> Of course maybe the "correct" way of doing this is to ditch the > OS ROMs altogether and roll your own bespoke app which talks to > the bare hardware and lives in the normal ROM sockets - any > attached disks are then purely for entertainment data.
Well, that sounds a bit hairy, given you'd have to write your own IDE, serial, etc drivers, worry about the MMU, cache, interrupts and so on. No doubt you could install an ARM micro-OS, but RISC OS is almost as good as that for this application. What you could do is roll your own RISC OS ROMs with all the other software in ROM (there's an article on the technical documents page on my website to do this in RO3.1), but loading a few bits off compactflash isn't a big deal.
In message <FAf*Cc...@news.chiark.greenend.org.uk> Theo Markettos <theom+n...@chiark.greenend.org.uk> wrote:
> Jules <julesrichardso...@remove.this.yahoo.co.uk> wrote: > > Hmm. For a car system with an LCD (presumably run via a serial or parallel > > port?) as the main display, there's no *need* for normal graphical video > > output either. Whether the system would power up and initialise without > > any video is another matter.
> IIRC the +12V is required for the analogue video output. So it'll work > quite happily with no +12V, it's just like nothing is connected to the > monitor port. Also you can switch the VIDC into digital out (to the Genlock > header) and it won't need +12V - you can then drive a laptop screen LCD from > that.
Not having to use 12v would help in keeping the computer alive during engine cranking, a problem that some dc-dc supplys have. If it wasn't for the -5v needed for the audio all you would need is a heavy +5v regulator.
I would like to now more about how to do the lcd connections as this would obviously be a big power saver. This would be a great project especially nowadays with the advances of LCD's, Solar panels, batteries and so on. TIA -Ron
Ron <b...@woosh.co.nz> wrote: > I would like to now more about how to do the lcd connections as this > would obviously be a big power saver. This would be a great project > especially nowadays with the advances of LCD's, Solar panels, batteries > and so on. TIA -Ron
has details for the rather strange Acorn A4 monochrome panel, but it links to an ARM application note which tells you (section B) how to attach a colour LCD to an ARM7500. The ARM7500 contains a VIDC20, so the same should apply to a Risc PC (though I haven't actually tried it).
Theo Markettos wrote: > Jules <julesrichardso...@remove.this.yahoo.co.uk> wrote: >> Hmm. For a car system with an LCD (presumably run via a serial or parallel >> port?) as the main display, there's no *need* for normal graphical video >> output either. Whether the system would power up and initialise without >> any video is another matter.
> IIRC the +12V is required for the analogue video output. So it'll work > quite happily with no +12V, it's just like nothing is connected to the > monitor port. Also you can switch the VIDC into digital out (to the Genlock > header) and it won't need +12V - you can then drive a laptop screen LCD from > that.
Could I connect up a TFT (Harvested from a damaged home screen) which is in colour? (1024 X 768 X 256)
Michael Emerton <MichaelREmer...@hotmail.com> wrote: > Could I connect up a TFT (Harvested from a damaged home screen) which is > in colour? (1024 X 768 X 256)
Yes, assuming it has a parallel input (nothing to do with parallel printer ports). See the colour panel section of the ARM datasheet linked from my page for the sort of thing it means. Some more modern screens use LVDS (low voltage differential signalling, a form of serial input) for which Simtec make a converter between the Risc PC and LVDS (actually it's for their RiscStation board, but it should work on a RPC too). Do you have the datasheet for you panel, or can you find it on the net? That'll be the first place to start.
> Or is it still restricted to 640x480x4?
No, though the VIDC's digital out is only 8 bits wide, so for 16-bit displays you have to double-clock it, which means you might hit the VIDC's bandwidth limits. I can't remember exactly what the limit is, but I'm sure 800x600 has been done so don't see why 1024x768 at 8 bit shouldn't be possible.
Theo Markettos wrote: > Michael Emerton <MichaelREmer...@hotmail.com> wrote: >> Could I connect up a TFT (Harvested from a damaged home screen) which is >> in colour? (1024 X 768 X 256)
> Yes, assuming it has a parallel input (nothing to do with parallel printer > ports). See the colour panel section of the ARM datasheet linked from my > page for the sort of thing it means. Some more modern screens use LVDS (low > voltage differential signalling, a form of serial input) for which Simtec > make a converter between the Risc PC and LVDS (actually it's for their > RiscStation board, but it should work on a RPC too). Do you have the > datasheet for you panel, or can you find it on the net? That'll be the > first place to start.
Slight problem there, its a cheap LCD (£100 over 4 years ago!) and I have no idea where it came from, as my Parents brought it.
As the screen is so old, I assume its parellel?
I will do some digging.
>> Or is it still restricted to 640x480x4?
> No, though the VIDC's digital out is only 8 bits wide, so for 16-bit > displays you have to double-clock it, which means you might hit the VIDC's > bandwidth limits. I can't remember exactly what the limit is, but I'm sure > 800x600 has been done so don't see why 1024x768 at 8 bit shouldn't be > possible.
I hadn't realised this was possible! 800x600 would be ok, but latter would be better for listing Music Data!
Michael Emerton <MichaelREmer...@hotmail.com> wrote: > Slight problem there, its a cheap LCD (?100 over 4 years ago!) and I > have no idea where it came from, as my Parents brought it.
> As the screen is so old, I assume its parellel?
Very much depends. I haven't taken a desktop LCD apart, but it might be the panel doesn't have the same interface as in a laptop.
> I will do some digging.
Start looking for model numbers on the LCD or the chips on it and having a Google will probably be the best way. This discussion forum is probably the best resource for LCD info on the net: http://www.eio.com/lcdintro.htm
