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TMS9918
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==Product family== All of the ICs in this family are usually referred to by the TMS9918 name, sometimes with an 'A' postfix. The 'A' indicates a second version of the chip which added new features, most prominently the addition of a [[bitmap]] mode (Graphic II). {| class="wikitable sortable" style="margin-left: auto; margin-right: auto; border: none;" |+ Texas Instruments TMS9918 Product Family Summary |- ! Chip Variant ! Video Out ! Video In ! Video Frequency ! Mode 2 Support |- | 9918 | [[Composite video|Composite]] | Composite | [[525 lines|60 Hz]] | No |- | 9918A / 9118 | Composite | Composite | 60 Hz | Yes |- | 9928A / 9128 | [[YPbPr]] | (None) | 60 Hz | Yes |- | 9929A / 9129 | YPbPr | (None) | [[625 lines|50 Hz]] | Yes |} ===TMS9918=== The '''TMS9918''' was only used in the TI-99/4; the [[TI-99/4A]] and the other computers had the A version VDC. === TMS9918A, TMS9928A and TMS9929A === [[IMAGE:TMS9928A 01.jpg|thumb|VDP TMS9928A]] The '''TMS9918A''' and '''TMS9928A''' output a [[525 lines|60 Hz video signal]], while the '''TMS9929A''' outputs 50 Hz. The difference between '1' and the '2' in 'TMS9918A' and 'TMS9928A' is that the '1' version outputs [[composite video|composite]] [[NTSC]] video, while the '2' versions (including the TMS9929A) outputs analog Y [[luma (video)|luminance]] and R-Y and B-Y colour difference signals. The need for the latter was predominant in the [[625 lines|50 Hz world]], including Europe, due to the different video signal standards [[PAL]] and [[SECAM]]. It was more cost-effective to output Y, R-Y and B-Y and encode them into PAL or SECAM in the [[RF modulator]], than to try to have a different console for every different color standard. The '1' version also features an external composite video input which made it a handy chip to use in video "titlers" that could overlay text or graphics on video, while the '2' version does not. The original variants of the TMS9918 were depletion load NMOS and manufactured on a 4.5 μm process; it was one of the first depletion load NMOS chips Texas Instruments manufactured in contrast to the [[TMS9900]] microprocessor which used the older enhancement load NMOS process that required three supply voltages. Due to the large die size and relatively high internal speed, the TMS9918 ran warm enough to necessitate a heat sink; some devices such as the Taiwanese DINA console (a hybrid Colecovision/SG-1000) neglected to install sinks and suffered from malfunctions of the chip. By 1983 Texas Instruments had shrunk the die size to 3 μm which ran cooler and no longer required a sink; MSX machines and the Sega SG-1000 used the newer 3 μm TMS9918 while most Colecovisions had the original 4.5 μm variant (the final run of the consoles produced in 1985 had the newer model TMS9918). ===TMS9118, TMS9128 and TMS9129=== [[File:VDP TMP9118.png|thumb|VDP TMP9118NL prototype]] A later variant of the TMS9918 series chips, the '''TMS9118''', '''TMS9128''', and '''TMS9129''', were released in the mid-late 1980s, but were never very popular. The function of one pin is changed, and the mapping of the video memory allows two 16K×4-bit chips to be used instead of the eight 16K×1-bit chips the TMS99xx needs. Otherwise the chips are completely identical to the TMS9918A, TMS9928A and TMS9929A respectively.
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