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Reader claims breakthrough on S370 CuMine compatibility

Yah booh sucks Intel

A reader, Diego von Deschwanden, has claimed a breakthrough with the knotty problem of whether current Socket 370 mobos will support flip chip PGAs (that is, when you can get hold of them). Diego writes: When Intel launched the FC-PGA, we all asked ourselves if our present Socket 370 motherboards with PPGA Celerons would support the flip-chip Coppermine processor. A few points of compatibility are to be taken into consideration: physical, voltage, pinout, and Bios support. This page at the Intel site explains Motherboard Compatibility: And this paragraph is very interesting: "Current motherboards designed for Intel® Celeron™ processors in the 370-pin socket Legacy motherboards designed for the 370-pin socket will not support the Pentium III processor in the FC-PGA form factor. "Pentium III processors in the FC-PGA have two RESET pins, and require VRM 8.4 specifications. The existing motherboards are referred to as Legacy motherboard, and the newer motherboards supporting the second RESET pin and VRM 8.4 are referred to as flexible motherboards. Contact your PC manufacturer for motherboard information" What is important: two RESET pins and the VRM 8.4 specification. Let's talk about VRM 8.4 first: the PIII Coppermine processors use 1.60 to 1.65 core voltage. These voltages are already selectable in a lot of recent motherboards, especially the Abit ones, wich you can select in Bios manually. (voltages from 1.30 to 2.05+ are supported). So core voltage shouldn't be an incompatibility issue. Then the best part: The two RESET pins: Further statements are made over these public (free, available) Intel documents: Pinout and RESET information source: Pentium(r) III Processor for the PGA370 Socket at 500E MHz and 550E MHz Here and here.(This will be DOC 1) Celeron datasheet source: here and here Closely looking at the pinout of PIII FC-PGA compared to the PPGA Celeron, we can notice that they have the same pinout except for two pins: For the Celeron: AH4 is RESET#, X4 is reserved. For the PIII FC-PGA: X4 is RESET#, and AH4 is now RESET2# As you see the RESET# pin has moved from AH4 to X4. The RESET# pin is essential to the processor, it wouldn't boot at all if it was not supplied. So suppose you wanted to use a Celeron in an Coppermine motherbord, the RESET# pin has changed, how can a Celeron be supported?: Read in DOC 1, page 46: "RESET# signal must be connected to pins AH4 and X4 for backwards compatibility. Refer to the platform design guide and Section 7.1 for implementation details. If backwards compatibility is not required, then RESET2# (X4) should be connected to GND." It is clear that if a Celeron is inserted, the AH4 and X4 must be connected so the Celeron can have access to the RESET# supply. Also it is obvious that if the board is to be used with PIII FC-PGA processors only, then this connection is not needed. I would like to bring your attention on the fact that Slot 1 (now called SC242) Coppermine PIII's do not have this RESET2# implemented…So let's see what this new RESET2# pin is about: Read DOC 1, page 68: "RESET2# The RESET2# pin is provided for compatibility with other Intel Architecture processors. The Pentium III processor does not use the RESET2# pin. Refer to the platform design guide for the proper connections of this signal." So the RESET2# is not used! This is where you say: "Hey! Wait a minute!" Not only the RESET2# is not used, but also the only functional and important pin has been moved. Intel is tricking us badly! Obviously Intel wants us to buy i810, i820,etc motherboards. Of course, it is all not about pins and voltage. There may be other minor timing and voltage incompatibilities. Only testing will tell. But nether the less, the RESET2# pin is quite an invention! ® Diego can be contacted at this email address ®

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