Re: DTV questions

From: Daniel Kahlin (
Date: 2005-11-25 17:20:39

On Fri, 25 Nov 2005, Ullrich von Bassewitz wrote:

> I've got my box with PAL DTVs yesterday. First step was of course to open the
> case and have a look at the interior:-) After a few hours of playing and
> checking the easter eggs, I downloaded the programming info. I will have a
> second look at it today, but for now, I have a few questions:
>  * Are there official or semi-official names for the new opcodes $32 and $42?

I'm wondering this too!  I saw someone use a name for one of them.  I 
think it was "SIR".  Could mean "Set Index Register" or something $42. 
In that case the other one could possibly be SAC $32.

>  * Is there any way to read the current register file assignment? The problem
>    I see is with libraries, interrupt handlers and such. If any subroutine
>    changes the register file assignments, it cannot restore the old contents.

The manual doesn't say, but maybe there is an undocumented way.

>  * There is no description for the register bank entries $10 and $11. Is it
>    correct that they are just the high bytes of the ZP and stack pages,
>    meaning that I can moves these two pages aroung in memory in 256 byte
>    steps?

You mean $a and $b ofcourse, and yes, that is what I understood from the 
manual, but will test tonight.

>  * This one is more a hardware question: How good is buffering on the
>    in-/outputs used for the serial IEEE port, the PC keyboard and so on?
>    Is it safe to just connect these to standard sockets/cables?

It seems fine to connect the pins straight out.  It is difficult to buffer 
them because they are mostly bidirectional.  The DTV-ASIC seems to have 
open-drain outputs on all those pins (according to the manual pdf) and it 
is a modern asic technology compared to the old Commodore NMOS-process, so 
it should have fairly good ESD-protection.

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