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base:efficient_tod_initialisation

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base:efficient_tod_initialisation [2019-05-12 20:34]
silverdr
base:efficient_tod_initialisation [2019-05-17 12:58] (current)
silverdr [Dual purpose]
Line 62: Line 62:
     ; we run on PAL machine with 60Hz TOD clock     ; we run on PAL machine with 60Hz TOD clock
 </​code>​ </​code>​
-we can determine not only the TOD frequency but also the video standard. This is possible because – unlike ​the TOD frequency – the CPU clock frequency is directly related to the computer'​s video standard. PAL computers have their CPU (and CIAs) clocked at 985248.444Hz while NTSC ones run faster and have their CPU/CIAs clocked at 1022727.14Hz. This is a side-effect of deriving all (except TOD) required clock frequencies from a single crystal of either 14318180Hz (for NTSC machines) or 17734472Hz (for PAL ones).+we can determine not only the TOD frequency but also the video norm. This is possible because – unlike TOD frequency – the CPU clock frequency is directly related to the computer'​s video standard. PAL computers have their CPU (and CIAs) clocked at 985248.444Hz while NTSC ones run faster and have their CPU/CIAs clocked at 1022727.14Hz. This is a side-effect of deriving all (except TOD) required clock frequencies from a single crystal of either 14318180Hz (for NTSC machines) or 17734472Hz (for PAL ones).
base/efficient_tod_initialisation.1557686044.txt.gz · Last modified: 2019-05-12 20:34 by silverdr