From: Daniel Kahlin (tlr_at_stacken.kth.se)
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.
http://www.kahlin.net/~tlr/dtv/
http://www.kahlin.net/~tlr/dtv_mod/
/Daniel
Message was sent through the cbm-hackers mailing list
Archive generated by hypermail pre-2.1.8.