Posted By
Exin
on 2008-03-05
17:19:17
|  Register Questions
Hi there. 2 questions(mainly from SVS's rommap):
In ECM, what is meant with normal characters? (bit 3 in the attribute bytes)
What happens if i set the multicolor bit in ECM?
Thanks in advance!
Your Exin
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Posted By
IstvanV
on 2008-03-05
17:43:41
| Re: Register Questions
If you mean setting both ECM and multicolor mode at the same time, it makes all pixels black (same for ECM + bitmap).
The bit 3 of attribute bytes has no special meaning in ECM mode, you can use all the 16 colors as the text color. Bit 7 is ignored, there is no flash effect. Reverse mode is also not possible, the character set is limited to 64 characters, but is aligned to 2K in memory as if there were 256 characters. There is also no cursor.
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Posted By
Exin
on 2008-03-05
18:16:59
| Re: Register Questions
So it is just a mistake in his desciption of the attribute bytes in that html-table?
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Posted By
IstvanV
on 2008-03-06
06:08:14
| Re: Register Questions
Probably yes. It is also not correct that bit 7 controls flashing in multicolor and ECM modes, in fact, it is ignored.
Some other minor errors I have noticed: the single clock mode bit in FF13 is inverted, and the formulas for calculating sound generator frequencies are not correct (the constants for PAL and NTSC are swapped, and the value in the registers is actually offset by one, so 1022 is the highest frequency, and -1 (= 1023) is the lowest one).
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Posted By
IstvanV
on 2008-03-06
06:12:36
| Re: Register Questions
Another correction: the PAL sound frequency constant should be 110840.45, rather than 111840.45.
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Posted By
SVS
on 2008-03-06
07:14:19
 | Re: Register Questions
Hello,
while I'm sorry for the mistakes (that surely I'll fix with next release of Ultimate-Plus4-Map), I thank you for the checking work.
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Posted By
Exin
on 2008-03-06
11:22:06
| Re: Register Questions
hi svs. Please also change that "from Color 3,x,y" stuff to actual registers, thanks. 
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