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
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