APU Oscillator: Difference between revisions

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.

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

@@ Line 5: / Line 5: @@
 * 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."  It does not clock the [[S-SMP]] directly.
+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 ===
 * [[OSC]]
+* [[Bit Clock]]
 === References ===
+# http://problemkaputt.de/fullsnes.htm#snestimingoscillators
-* 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
-* [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:Audio]]
 [[Category:Timing]]