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APU Oscillator: Difference between revisions
From SnesLab
(S-DSP is not connected to MCK so it has to be getting its clock from the APU OSC) |
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The '''APU oscillator''' (X2) is clocked at 24.6 MHz, slightly faster than the [[master clock]]. | The '''APU oscillator''' (X2) is clocked at 24.6 MHz, slightly faster than the [[master clock]]. | ||
* Side 1 is XTALO, connected to pin 45 of the [[S-DSP]]. | * Side 1 is XTALO, connected to pin 45 of the [[S-DSP]] and C72. | ||
* Side 2 is XTALI, connected to pin 46 of the [[S-DSP]]. | * Side 2 is XTALI, connected to pin 46 of the [[S-DSP]] and C71. | ||
XTAL stands for "crystal. | It is not connected to anything else. XTAL stands for "crystal," but according to a board photo<sup>[3]</sup> X2 is actually a ceramic oscillator. It does not clock the [[S-SMP]] directly. | ||
=== See Also === | === See Also === | ||
* [[OSC]] | * [[OSC]] | ||
* [[Bit Clock]] | |||
=== References === | === References === | ||
# http://problemkaputt.de/fullsnes.htm#snestimingoscillators | |||
# [https://archive.org/details/SNESDevManual/book1/page/n98 Figure 2-22-1 on page 2-22-2] of the official Super Nintendo development manual | |||
# Sanglard, Fabien. The Hearts of the Super Nintendo. https://fabiensanglard.net/snes_hearts | |||
[[Category:SNES Hardware]] | [[Category:SNES Hardware]] | ||
[[Category:Audio]] | [[Category:Audio]] | ||
[[Category:Timing]] | [[Category:Timing]] | ||
Latest revision as of 19:10, 18 August 2024
The APU oscillator (X2) is in region 3C of the jwdonal schematic
The APU oscillator (X2) is clocked at 24.6 MHz, slightly faster than the master clock.
- Side 1 is XTALO, connected to pin 45 of the S-DSP and C72.
- Side 2 is XTALI, connected to pin 46 of the S-DSP and C71.
It is not connected to anything else. XTAL stands for "crystal," but according to a board photo[3] X2 is actually a ceramic oscillator. It does not clock the S-SMP directly.
See Also
References
- http://problemkaputt.de/fullsnes.htm#snestimingoscillators
- Figure 2-22-1 on page 2-22-2 of the official Super Nintendo development manual
- Sanglard, Fabien. The Hearts of the Super Nintendo. https://fabiensanglard.net/snes_hearts