Subject: [stella] TIA video timing From: Adam Wozniak <adam@xxxxxxxxxxxxxxxx> Date: Thu, 10 Mar 2005 00:08:07 -0500 |
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 I've been scratching my head here for a while, and I'm still not certain I've got this right. Can someone give me a yea or nay on this? - -- posNOW is a 8 bit counter, that goes up from 0 to 227 - -- regVSYNC is bit 1 of TIA register address VSYNC - -- regVBLANK(0) is bit 1 of TIA register address VBLANK - -- sync is the sync output pin of the TIA (pin 2) - -- nblk is the bl output pin of the TIA (pin 6) - -- video sync output process (posNOW) begin if posNOW = "11100000" then -- 11100000 == 224 sync <= not ('1' xor regVSYNC); elsif posNOW = "01000000" then -- 01000000 == 64 sync <= not ('0' xor regVSYNC); end if; end process; - -- video blank output process (regVBLANK) begin nblk <= not regVBLANK(0); end process; Once I'm sure I've got this right, I can move into testing. - -- adam@xxxxxxxxxxxxxxxx http://cuddlepuddle.org/~adam KG6GZR http://cuddlepuddle.org/~adam/resume.html -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.1 (GNU/Linux) iD8DBQFCL8S2yvXf5Z0z5zERAntRAJ91i15gktf30t1SdwF6zayOh1YC0QCgm8NJ Fm/Phn5Gpf7pXYEolhnTEbA= =bHa5 -----END PGP SIGNATURE----- Archives (includes files) at http://www.biglist.com/lists/stella/archives/ Unsub & more at http://stella.biglist.com
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