X0858CE
The X0858CE is a video transcoder chip used in the Sharp Famicom Titler (AN-510) and Sharp X1 Turbo III systems[1]. It is responsible for taking the 2C05-99 chip’s RGB output, and transcoding it into composite and S-Video, with adjustments to saturation using external components, specifically a 0.5 gain on the R-Y and B-Y color difference channels on pin 11 and pin 12 (U = U * 0.5; V = V * 0.5). This results in a desaturated color output for the internal Famicom. The chip is also accompanied by a 3.579545 MHz crystal and supporting components such as a variable capacitor on pins VA, VB and VC (pins 7, 8, and 9 respectively), alongside other components for adjusting other aspects of the video output.
This chip is also responsible for the “superimposing” video feature that the Titler is built for. The YIV and CIV pins (pins 24 and 3 respectively) are inputs for external video, and the YS pin (pin 26) switches between external video and internal video source from the YIC/B-YI/R-YI pins (pins 21, 14, and 13 respectively).
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COM <- |01 30| <- CIM
ACCF -- |02 29| -> VO
CIV -> |03 28| <- YIM
BIPASS -- |04 27| -> YOM
/BEP -- |05 26| <- YS
TINT_C -> |06 25| <- YM
VC ?- |07 24| <- YIV
VB ?- |08 23| -? /PCP
VA ?- |09 22| -- VCC
PDO -- |10 21| <- YIC
R-YO <- |11 20| -> YOC
B-YO <- |12 19| <- RI
R-YI -> |13 18| <- GI
B-YI -> |14 17| <- BI
GND -- |15 16| <- COLOR-C
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