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base:efficient_tod_initialisation [2019-05-12 20:32] – [TOD initialisation - the problem] silverdrbase:efficient_tod_initialisation [2019-05-12 20:34] silverdr
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 First let's say how NOT to do it. It is important to note that contrary to a very popular and utterly wrong belief, NTSC or PAL video/colour encoding standards are NOT directly linked to mains power frequency. This means that checking which video standard the machine is of, should never be used to make assumptions about what the TOD frequency is. Not only PAL computers can be used in countries with 60Hz AC (and vice versa - NTSC computers can be run of 50Hz power) but in addition to that some computers do not derive their TOD clock frequency from the mains power source at all. For example both NTSC and PAL variants of Commodore SX-64 use 60 Hz TOD clock supplied by a dedicated crystal. First let's say how NOT to do it. It is important to note that contrary to a very popular and utterly wrong belief, NTSC or PAL video/colour encoding standards are NOT directly linked to mains power frequency. This means that checking which video standard the machine is of, should never be used to make assumptions about what the TOD frequency is. Not only PAL computers can be used in countries with 60Hz AC (and vice versa - NTSC computers can be run of 50Hz power) but in addition to that some computers do not derive their TOD clock frequency from the mains power source at all. For example both NTSC and PAL variants of Commodore SX-64 use 60 Hz TOD clock supplied by a dedicated crystal.
 ===== Proper solution ===== ===== Proper solution =====
-While there are various approaches to this problem, we believe the one presented below is not only the most compact but can also serve dual purpose, increasing the byte-size savings even further.+While there are various approaches to this problem, we believe the one presented below is not only the most compact but can also serve dual purpose (see below), increasing the byte-size savings even further.
 <code 6502acme> <code 6502acme>
 ; Detecting TOD frequency by Silver Dream ! / Thorgal / W.F.M.H. ; Detecting TOD frequency by Silver Dream ! / Thorgal / W.F.M.H.
base/efficient_tod_initialisation.txt · Last modified: 2020-10-27 02:31 by silverdr