elg@killer.UUCP (Eric Green) (09/18/87)
On page 265 of my Programm's Ref (C-64), for the map at the bottom, it says
that for loram=1,hiram=1,game=0,exrom=0, an 8K ROM cartridge is switched into
$8000-$A000.
On page 266, for the map at the bottom, it says that for
loram=1,hiram=1,game=0,exrom=0, a 16K ROM cartridge is switched into
$8000-c000.
Same signals, two different memory maps??? Something's not right here!
Also, another question -- is the *SRQIN line ever used, at all, in a Commodore
64? Is its connection to the *FLAG line on CIA#1 ever used in the disk
routines of either the C64 or C128? Seems that the fast disk mode clickin'
away would give that *FLAG line a lot of excercise!
--
Eric Green elg@usl.CSNET "... hanging on in quiet desperation
{cbosgd,ihnp4}!killer!elg is the english way,
Snail Mail P.O. Box 92191 the time is gone, the song is over,
Lafayette, LA 70509 thought I'd something more to say....."fred@cbmvax.UUCP (Fred Bowen) (09/21/87)
This is a re-posting of something that I originally posted last Friday after a system crash- the system date was fubar, and you may not have seen it. In article <1556@killer.UUCP>, elg@killer.UUCP (Eric Green) writes: > > On page 265 of my Programm's Ref (C-64), for the map at the bottom, it says > that for loram=1,hiram=1,game=0,exrom=0, an 8K ROM cartridge is switched into > $8000-$A000. > > On page 266, for the map at the bottom, it says that for > loram=1,hiram=1,game=0,exrom=0, a 16K ROM cartridge is switched into > $8000-c000. > > Same signals, two different memory maps??? Something's not right here! > > Also, another question -- is the *SRQIN line ever used, at all, in a Commodore > 64? Is its connection to the *FLAG line on CIA#1 ever used in the disk > routines of either the C64 or C128? Seems that the fast disk mode clickin' > away would give that *FLAG line a lot of excercise! > You found an old typo in the manual- the memory map with 8K of cartridge ROM should specifiy /game=1, not /game=0 (not, these are inverted signals). The map with 16K of cartridge ROM is correct as it is. The SRQ line is simply passed to the user port in the 64 *and* 64 mode of the 128- this allows little Johnny's weather station to work. In 128 mode, this line is used by the fast/burst serial routines- little Johnny's station won't work so good here. -- -- Fred Bowen uucp: {ihnp4|rutgers|caip}!cbmvax!fred arpa: beats me tele: 215 431-9100 Commodore Electronics, Ltd., 1200 Wilson Drive, West Chester, PA, 19380
cg13+@andrew.cmu.edu (Curtis C. Galloway) (09/25/87)
>On page 265 of my Programm's Ref (C-64), for the map at the bottom, it says >that for loram=1,hiram=1,game=0,exrom=0, an 8K ROM cartridge is switched into >$8000-$A000. > >On page 266, for the map at the bottom, it says that for >loram=1,hiram=1,game=0,exrom=0, a 16K ROM cartridge is switched into >$8000-c000. > >Same signals, two different memory maps??? Something's not right here! All is well. Note that $A000-$8000 = 8192 bytes = 8K, while $C000-$8000 = 16384 bytes = 16 K. The 16K ROM takes up twice the space of the 8K ROM, so the memory maps must be different -- but they both start at the same address, $8000. --Curt Galloway cg13+@andrew.cmu.edu ...ucbvax!andrew.cmu.edu!cg13+