more clarification

Signed-off-by: Leah Rowe <info@minifree.org>
master
Leah Rowe 2024-09-26 12:17:56 +01:00
parent 10fdd82ab6
commit 3ac406b6f6
1 changed files with 9 additions and 3 deletions

View File

@ -169,16 +169,18 @@ on PAL consoles (and vice versa); RGB SCART can be used to mitigate the colour
issue, but not the timing issue. The oscillator mod is the only solution for the
timing issue.
The PAL GPU clock is roughly 53.2MHz, and divides by 12 to create the PAL
The PAL GPU clock is roughly 53.2MHz, and divides by 12 to create the 4.43MHz PAL
subcarrier/colorburst signal; this is needed in composite video for example.
The NTSC GPU clock is 53.693175MHz, and divides by 15 to create the NTSC
The NTSC GPU clock is 53.693175MHz, and divides by 15 to create the 3.58MHz NTSC
subcarrier/colorburst signal; ditto, this is used for NTSC composite video.
On a PAL playstation, Sony woride 53.2MHz to both inputs, and on NTSC, wired
53.69MHz to both inputs; that means on NTSC machines, PAL games will run with
a 3.579545MHz colorburst signal, and on PAL consoles running NTSC games,
the colorburst would be 3.55MHz.
the colorburst would be 3.55MHz. *Some* people suggest hardwiring a 4.43MHz
clock to the video dac/buffer on PAL consoles, thus creating what is called
a "PAL60" signal, but this is ill advised; ditto wiring 3.58MHz to it (NTSC50).
On *most* consoles except very early launch/debug models, and *very late* slim
models, the PAL clock is pin 192 on the GPU and NTSC is pin 196 on the GPU.
@ -193,6 +195,10 @@ and hook up 53.2MHz to it. The Dual Frequency Oscillator method is easier and
therefore recommend, but you can do this other method, which I call *DO* (Dual
Oscillator. Because it's two oscillators!)
By fixing the timings in this way, your region-free console will also have
correct timings, thus maximum game compatibility, and colours will always be
correct no matter what video cable you're using.
Modchips
--------