+retroclouds Posted May 26, 2020 Share Posted May 26, 2020 What is the proper way to reset the F18a extended registers so that they have the same values as after a clean power-up cycle? Reason I'm asking is that if you change extended VDP registers the settings stay active even after down a "BLWP @0". In this particular case I have a crash handler in my assembly program that resets the TI to a defined state. But obviously I do not know what was set in the F18a extended registers by the calling program before. Could keep track of any value written to the F18a registers, but with the many extended registers that may get cumbersome. In my last example I turn on position-based attributes, but obviously if I reset the TI, the screen is unreadable. I know how to resolve this particular case, but would prefer a generic solution. 2 Quote Link to comment Share on other sites More sharing options...
PeteE Posted May 26, 2020 Share Posted May 26, 2020 ? 3 Quote Link to comment Share on other sites More sharing options...
+retroclouds Posted May 26, 2020 Author Share Posted May 26, 2020 oh wow, just got that time-warp feeling again. Thanks for pointing out the answer to a question I already asked in 2018 ? 5 Quote Link to comment Share on other sites More sharing options...
GDMike Posted May 26, 2020 Share Posted May 26, 2020 Could it not be saved prior, just asking. Quote Link to comment Share on other sites More sharing options...
matthew180 Posted May 26, 2020 Share Posted May 26, 2020 (edited) Note that the palette registers are *not* reset. They are implemented as a memory, which needs to be addresses one location at a time, and only gets an initial setting when the FPGA loads its bit-stream at power on. That means, any changes you make to the first 16 palette registers will change the "standard" 16-colors used when the F18A is locked or before the palette-select bits are changed (only possible when the F18A is unlocked). Edited May 26, 2020 by matthew180 1 Quote Link to comment Share on other sites More sharing options...
Omega-TI Posted May 26, 2020 Share Posted May 26, 2020 This brings up a question. Sometimes things get messed up, other times I'd simply like to clear PALEA5... without power cycling the TI. Would it be possible to make a small E/A5 reset program? Quote Link to comment Share on other sites More sharing options...
+jedimatt42 Posted May 26, 2020 Share Posted May 26, 2020 55 minutes ago, GDMike said: Could it not be saved prior, just asking. We are used to the 9918 registers mostly being write-only. So we think in our soul that the answer is no... but once the F18A is unlocked, the answer changes to yes. However, it is less code (if the intent is to dump back to the title screen) to ask the F18A to reset what it can, and then let the console rom do the rest... 1 Quote Link to comment Share on other sites More sharing options...
Tursi Posted May 27, 2020 Share Posted May 27, 2020 My Slideshow program has a reset sequence that includes palette, if someone is after sample code. http://harmlesslion.com/software/slideshow99 6 Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.