Date: Fri, 31 May 2002 08:21:13 +0800 From: Raymond <[EMAIL PROTECTED]> Subject: Re: [LIB] Info about the keyboard and mouse ports ...
Bleh ... OK I DID say I didn't know what I was doing! For some reason, when I was tracing the pins to the PS/2 controller, I somehow missed the fact that there WAS actually more than a negligible amount of resistance between the external ports and the pins on the controller. It turns out, there is about 150 ohms between the external ports and that PS/2 controller chip. It also turns out that the high density surface mount pins on that controller chip are REALLY hard to solder to if you're a student and can only afford a really cheap iron... So I did some more poking around and figured out where the pins come out onto a resistor array (single 8 pin SMD package with 4 resistors in it) on the back of the board which is, not surprisingly, marked 151 (15E1 or 150 ohms). Its possible to follow the PCB traces from the other side of that resistor array right to the docking connector (well OK you have to take a guess under the flatpack IC), plus I get about 0.2 ohms between THAT side of the resistor array and the docking connector, so I'm *pretty* sure I got the right one this time ;-) ... as a bonus, that resistor array looks to be a LOT easier to solder to than the pins on the controller array (its still surface mount but the 'legs' are set in to the packaging so I'd imagine it'd be a lot harder to bridge them). The resistor array I'm talking about appears on the underside of the board, just under the side of the battery connector that has the plastic spacer. There are 3 surface mount resistor arrays, one marked 151 (150 ohms) appears to have all of the terminals on one side tied, 1 to 1, to an array marked 104 (I'm guessing thats 10Kohms). I'm guessing the 10K array consists of tie-ups, which would make sense. The pins to solder to would be either of the pins on either side of the link between the 150 ohm array and the 10K array (ie. the side of the 150 ohm array furthest from the battery connector). From left to right (with the ROM chips on the left), the pins would be mouse data, mouse clock, keyboard data and keyboard clock. If anyone is interested (IS anyone interested?) I can see if I can figure out some way of posting the picture of this thing up (the place I used to have my pages on decided to disappear on me so I gotta find some place else ...) - Raymond --- /~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\ | | "Does fuzzy logic tickle?" | | ___ | "My HDD has no reverse. How do I backup?" | | /__/ +-------------------------------------------| | / \ a y b o t | [EMAIL PROTECTED] | | | Need help? Visit #Windows98 on DALNet! | | ICQ: 31756092 | Libretto IRC channel #Libretto on DALNet! | \~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~/ ************************************************************** http://libretto.basiclink.com - Libretto mailing list http://www.silverace.com/libretto/ - Archives -------TO UNSUBSCRIBE------- Reply to any of the list messages. The reply mail should be addressed to: [EMAIL PROTECTED] - Then replace any text on the message's subject line: cmd:unsubscribe --------TO UNSUBSCRIBE DIGEST------ Do above but with this on subject line: cmd:unsubscribe digest **************************************************************
