DearHorse Posted January 29, 2020 Share Posted January 29, 2020 Hi all and , first, best wishes for 2020. Just a question about gr.10 (9 colors) mode to be sure to do not a mistake the colors cover $2C0 to $2C8 and values from 0 to 8 on 4bits bloc (1byte->2pixels). But setting values from 9 to 15 return this result : value 09 -> color 8 value 10 -> color 8 value 11 -> color 8 value 12 -> color 4 value 13 -> color 5 value 14 -> color 6 value 15 -> color 7 as values 12 to 15 seems less or more logical (forgetting bit 3) values from 9 to 11 don't. As it's for a gr.10 charset tool mode interpretation, I just ask to more skilled 8-bit atarians if it's correct to take values in previous list for visualisation of data on screen, or not ? have a nice day Quote Link to comment Share on other sites More sharing options...
emkay Posted January 29, 2020 Share Posted January 29, 2020 The question is: What do you intend? The values are 0 to 8 . More than 9 colors were not available. Why bothering with the upper values? Particular the GTIA chip has never been fully completed. So there are a lot registers unused or even illogic. Back in the days, it had been "the clue" to really use the numbers that have a direct usage, because an updated chip always would encounter problems , if the unused values get a real functionality. Quote Link to comment Share on other sites More sharing options...
+Stephen Posted January 29, 2020 Share Posted January 29, 2020 1 hour ago, DearHorse said: Hi all and , first, best wishes for 2020. Just a question about gr.10 (9 colors) mode to be sure to do not a mistake the colors cover $2C0 to $2C8 and values from 0 to 8 on 4bits bloc (1byte->2pixels). But setting values from 9 to 15 return this result : value 09 -> color 8 value 10 -> color 8 value 11 -> color 8 value 12 -> color 4 value 13 -> color 5 value 14 -> color 6 value 15 -> color 7 as values 12 to 15 seems less or more logical (forgetting bit 3) values from 9 to 11 don't. As it's for a gr.10 charset tool mode interpretation, I just ask to more skilled 8-bit atarians if it's correct to take values in previous list for visualisation of data on screen, or not ? have a nice day While modes 9 and 11 provides 16 "steps" for colour or brightness, mode 10 is special in that it can use any chosen colour. However, the machine only has 9 palette registers so unfortunately, only 9 colours can be used without tricks, not the full 16 from modes 9 and 11. Quote Link to comment Share on other sites More sharing options...
DearHorse Posted January 30, 2020 Author Share Posted January 30, 2020 (edited) 22 hours ago, emkay said: The question is: What do you intend? The values are 0 to 8 . More than 9 colors were not available. Why bothering with the upper values? Hi, why -> In text-mode, each line of character is 8bit, so when doing an interpretation of a char-line value bin 10011001 in gr.10 I must do something with this value 9 in 9color mode to have a visual result, even if it's a strange result or unusefull at the first approach. I know that there is no more than 9 colors availaible but as a nibble is already availaible to code a 9 color pixel, and machine doing an interpretation with upper values (my list in upper post), I ask if values seems correct to others skilled users (mainly on NTSC machines because mine are PAL, in various situations, ..) to do global work on chars with tool software. I post as screenshot to show sample interpretation with GR.11 txt mode (left) to gr.0 (right) as example of what I try to explain. bugs on C/GTIA are not a problem as long as they are the same everywhere. sorry for my bad english. best Quote Particular the GTIA chip has never been fully completed. So there are a lot registers unused or even illogic. Back in the days, it had been "the clue" to really use the numbers that have a direct usage, because an updated chip always would encounter problems , if the unused values get a real functionality. Thanks for response Edited January 30, 2020 by DearHorse 1 Quote Link to comment Share on other sites More sharing options...
Rybags Posted February 2, 2020 Share Posted February 2, 2020 Only 9 colour registers exist which is reason for the repeated results. A better idea IMO would have been to just use 8 colour registers in that mode then assign the high bit to something else like half brightness or inverted colour (probably better). 2 Quote Link to comment Share on other sites More sharing options...
Synthpopalooza Posted February 27, 2020 Share Posted February 27, 2020 One of the strange quirks of GTIA 10 is that the repeated color values will map differently when inverse characters are implemented. There is also the matter of nonstandard ANTIC settings, e.g. engaging ANTIC 4 or ANTIC 6 atop GTIA 10. These quirks I learned when programming my ICE editor. 1 Quote Link to comment Share on other sites More sharing options...
Synthpopalooza Posted February 27, 2020 Share Posted February 27, 2020 By the way your tool looks like it is coming off well. If you have any ICE mode questions, please ask me. 1 Quote Link to comment Share on other sites More sharing options...
fox Posted February 27, 2020 Share Posted February 27, 2020 Yes, you can safely use the values 9-15 if you need to. Your interpretation is correct and now that we have internal GTIA schematics, we know that this is how it works. Emulators have no problems either. 1 Quote Link to comment Share on other sites More sharing options...
Synthpopalooza Posted February 27, 2020 Share Posted February 27, 2020 (edited) 9 minutes ago, fox said: Yes, you can safely use the values 9-15 if you need to. Your interpretation is correct and now that we have internal GTIA schematics, we know that this is how it works. Emulators have no problems either. Specifically Altirra and I think Atari800 do not have problems. The problems arise if we engage Antic 4/5 on GTIA 10. Atari800win returns the wrong color for bit pattern %1000 in that mode, amongst others. Altirra has it right. Edited February 27, 2020 by Synthpopalooza 1 Quote Link to comment Share on other sites More sharing options...
Synthpopalooza Posted February 27, 2020 Share Posted February 27, 2020 As a feature suggestion: It might be useful to add the Antic 4/5 iterations of GTIA 9, 10, and 11 to the available modes in your editor. There are instances in interlacing modes, where this is useful ... First, if you want to use low resolution ANTIC 5. Second, using ANTIC 4 but using a scan line change to interweave the modes, rather than full screen flicker. I used this method on a remix of that Tetris clone called The Wall ... the game used ANTIC 4 but GTIA 11 is switched on alternately on scanlines to get 60 colors. The colors are mapped differently, and you only get 14 of the 16 settings. Quote Link to comment Share on other sites More sharing options...
DearHorse Posted March 4, 2020 Author Share Posted March 4, 2020 On 2/27/2020 at 7:00 PM, Synthpopalooza said: By the way your tool looks like it is coming off well. If you have any ICE mode questions, please ask me. Thanks Bobby, glad to hear you Quote Link to comment Share on other sites More sharing options...
DearHorse Posted March 4, 2020 Author Share Posted March 4, 2020 On 2/27/2020 at 7:12 PM, fox said: Yes, you can safely use the values 9-15 if you need to. Your interpretation is correct and now that we have internal GTIA schematics, we know that this is how it works. Emulators have no problems either. Thanks, So I keep the implementation of this. Quote Link to comment Share on other sites More sharing options...
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