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#1
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[P2B-D] -- question about connections
hello,
after some summer break I come back to the idea of modding my old p2b-d. I reviewed the document here http://tipperlinne.com/p2b-ds150.htm and want to make myself sure wheater the connections between pins are as follows: http://www.geocities.com/qroobas/ds-before.jpg I would use 2-pin FS3 instead of 3-pin if the third pin, the rightmost one, is unused. I would appreciate confirmation of these connections by the author or Paul or somebody, who has done such modification. thanks, geos |
#2
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geos wrote: hello, after some summer break I come back to the idea of modding my old p2b-d. I reviewed the document here http://tipperlinne.com/p2b-ds150.htm and want to make myself sure wheater the connections between pins are as follows: http://www.geocities.com/qroobas/ds-before.jpg No, that's incorrect. The leftmost pin (1) on all FSx jumpers is connected to Vio (3.3v) and the rightmost pin (3) to ground. The middle pin (2) is connected to the corresponding FSx input of the clock generator chip via a 10K ohm resistor, so you get a logic '1' applied to the clock generator's FSx pin when the jumper is set 1 - 2 and logic '0' when the jumper is set 2 - 3. I would use 2-pin FS3 instead of 3-pin if the third pin, the rightmost one, is unused. I would appreciate confirmation of these connections by the author or Paul or somebody, who has done such modification. thanks, geos The clock generator has an internal pull-down resistor to ground on FS3 (unlike FS[0-2], which have an internal pull-up), so a 2-pin jumper (pins 1 & 2 only) will work, but it leaves the 10K ohm programming resistor and attached wire floating when the jumper is removed - which could theoretically introduce noise on the PCI clock signal. Note that FS3 changes function from an input during reset to a clock output during operation. I follow the clock generator chip manufacturer's recommendation and install a 3-pin FS3 jumper. P2B |
#3
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In article , geos wrote:
hello, after some summer break I come back to the idea of modding my old p2b-d. I reviewed the document here http://tipperlinne.com/p2b-ds150.htm and want to make myself sure wheater the connections between pins are as follows: http://www.geocities.com/qroobas/ds-before.jpg I would use 2-pin FS3 instead of 3-pin if the third pin, the rightmost one, is unused. I would appreciate confirmation of these connections by the author or Paul or somebody, who has done such modification. thanks, geos This is my previous post: http://groups.google.com/groups?selm...0192.168.1.177 This is a schematic diagram of the wiring. +3.3V +3.3V ---X | 10K | X----/\/\/\---+ \ (Internal "strap" | / 240K GND ---X | \ Pullup ------------- | / Resistor) | | | | | | 22 ohm PCICLK0 |----+--+--/\/\/\--------- Clock to PCI slot | Series | Damping ------------- Resistor ("R99") Now, we redraw it physically: +------------------------------------- | | | | 10K ----------- | New Resistor | | X X X FS3 | | 9250 | | | ------R99---+-------Pin9| Clock | | | 22ohm PCICLK0| Gen | +----+ | | | | +----+ ----------- | | X X X FS0 X X X FS1 X X X FS2 (+3.3) (GND) All three pins of the new header are used. The end pins of FS3 are feeding from the end pins of FS0. All the left hand side FS pins are at 3.3V, and the right hand ones are at GND potential. The long wire goes from the center pin of FS3, to the end of the new 10K ohm resistor. The other end of the 10K ohm resistor is soldered to the junction of R99 (where the right hand side of R99 is soldered to its pad). This keeps the bottom end of the 10K resistor close to the circuit, keeping the stub length down. The wire going from the top of the 10K resistor isn't critical, so it doesn't have to be strung like a guitar string. Neither are the two wires running from the left and right header pins of FS3, when they connect to the left and right header pins on FS0. The photograph from Tipperlinne is deceptive and the photo should have been taken before the hot glue was added, or at least the solder joints should have been visible. HTH, Paul |
#4
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Paul wrote: In article , geos wrote: hello, after some summer break I come back to the idea of modding my old p2b-d. I reviewed the document here http://tipperlinne.com/p2b-ds150.htm and want to make myself sure wheater the connections between pins are as follows: http://www.geocities.com/qroobas/ds-before.jpg I would use 2-pin FS3 instead of 3-pin if the third pin, the rightmost one, is unused. I would appreciate confirmation of these connections by the author or Paul or somebody, who has done such modification. thanks, geos This is my previous post: http://groups.google.com/groups?selm...0192.168.1.177 This is a schematic diagram of the wiring. +3.3V +3.3V ---X | 10K | X----/\/\/\---+ \ (Internal "strap" | / 240K GND ---X | \ Pullup ------------- | / Resistor) | | | | | | 22 ohm PCICLK0 |----+--+--/\/\/\--------- Clock to PCI slot | Series | Damping ------------- Resistor ("R99") The internal resistor is actually a pull-down - that's why FS3 defaults to logic 0 when FS3 is omitted entirely (i.e. as shipped by Asus). Now, we redraw it physically: +------------------------------------- | | | | 10K ----------- | New Resistor | | X X X FS3 | | 9250 | | | ------R99---+-------Pin9| Clock | | | 22ohm PCICLK0| Gen | +----+ | | | | +----+ ----------- | | X X X FS0 X X X FS1 X X X FS2 (+3.3) (GND) All three pins of the new header are used. The end pins of FS3 are feeding from the end pins of FS0. All the left hand side FS pins are at 3.3V, and the right hand ones are at GND potential. The long wire goes from the center pin of FS3, to the end of the new 10K ohm resistor. The other end of the 10K ohm resistor is soldered to the junction of R99 (where the right hand side of R99 is soldered to its pad). This keeps the bottom end of the 10K resistor close to the circuit, keeping the stub length down. The wire going from the top of the 10K resistor isn't critical, so it doesn't have to be strung like a guitar string. Neither are the two wires running from the left and right header pins of FS3, when they connect to the left and right header pins on FS0. The photograph from Tipperlinne is deceptive and the photo should have been taken before the hot glue was added, or at least the solder joints should have been visible. Fair comment - I'll try to get a better picture next time I do one. HTH, Paul |
#5
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In article , P2B
wrote: snip The photograph from Tipperlinne is deceptive and the photo should have been taken before the hot glue was added, or at least the solder joints should have been visible. Fair comment - I'll try to get a better picture next time I do one. HTH, Paul It is difficult to keep everyone happy when doing engineering change documentation :-) At my previous employer, the factory would always redo the documentation we sent them, so it is all par for the course. The problem is, showing the big picture (how to lay out the wire and components) and zooming in on the individual connections. I've looked at a few volt modding sites, and some of the pictures are bad (blurry, or don't show detail where it is needed). Part of the problem is, you need a good macro capability on the camera, to get in close enough. With the gear I own, I couldn't do any volt mod pictures. Keep up the good work :-) Paul |
#6
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thank you P2B and Paul for the answers. really appreciated, will go foe
3pin then. cheers, geos |
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