[Coco] OS-9 80-column driver is ready

[Luis Antoniosi (CoCoDemus)]

The chip runs on +5V so I don't think it will burn anything here :). It
needs data strobe to work something more complicated to test without a
clock.

I already have the schematics and PCB done on Eagle cad.

The free edition size limitation is enough for a small pak PCB. But I will
prototype it on a breadboard to make sure it works before going to
production. Just waiting all my chinese crap to come...

The original prototype has some of the data bit traces inverted between the
CRT and SRAM according to the datasheet.

They made that way to reduce the number of vias. It's okay since the CRT is
the only to read and write on it so the bytes will always be in the correct
order.

But since I'm more pragmatic (OCD ?) I routed them the way they are on the
datasheet.




On Tue, Oct 8, 2013 at 4:38 PM, Tormod Volden <lists.tormod at gmail.com>wrote:

> On Tue, Oct 8, 2013 at 3:20 AM, Retro Canada wrote:
> > hi i actually found that my chip is labeled as crt9128-000. So the P
> stands for plastic.
>
> That's a good sign. I also got some hits on crt9128-000 and SMC.
>
> > i found several old stock suppliers from china. waiting a sample to
> arrive.
>
> Cool. It's the only way to find out, I guess. But unless the chip is
> labelled SMC, maybe you should try to verify the in/out pins before
> you connect it to your Tandy, or use a buffer in between like for
> instance Mark's CoCoBus. If an expected input turns out to be an
> output it might cause damage.
>
> Are you prototyping it on a breadboard or stripboard? If no one else
> does, I might look into making a PCB design. But I'll let you do the
> smoke testing first :)
>
> Regards,
> Tormod
>
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