Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10 5/3/83; site intelca.UUCP Path: utzoo!watmath!clyde!burl!ulysses!mhuxj!ihnp4!zehntel!dual!amd!intelca!glen From: glen@intelca.UUCP (Glen Shires) Newsgroups: net.micro Subject: IBM-PC Hardware RESET kluge -> Re: Turning machines on/off frequently Message-ID: <412@intelca.UUCP> Date: Mon, 24-Sep-84 21:30:29 EDT Article-I.D.: intelca.412 Posted: Mon Sep 24 21:30:29 1984 Date-Received: Wed, 26-Sep-84 07:49:47 EDT References: <13366@sri-arpa.UUCP> <189@dataio.UUCP> Organization: Intel, Santa Clara, Ca. Lines: 31 . Yes, While developing software for the PC, one often runs a program that has bugs that send the PC into never-never land and the only way to restart the system is to power it off/on. Using an XT with a hard disk, power cycling made me cringe. So, I added my own hardware reset switch by connecting a normally open pushbutton switch in series with a 300 ohm resistor to pins 1 and 6 of P1. P1 is one of the two plugs that connect the motherboard to the power supply, it is the rear plug and marked "P1". Pins 1 and 6 are at opposite ends of this 6 connector plug. This configuration grounds the PWRGOOD signal of the PC and thus resets the CPU. Now, not only can I reset the PC without powering on/off, but also if I tap the switch quickly enough, the PC will do a quick warm-boot rather than a time-consuming cold-boot that tests all the RAM. This is because the PC ROMs leave the value 1234h in a special location in RAM. After RESET, if this location contains 1234h, the memory tests are skipped. If this new RESET switch is not held down long enough that the DRAMs lose their contents, this value remains and a warm-boot is performed. NOTE: Sure, I invented this kluge, but neither I nor my company take any responsibility for it or any affects it causes! -- ^ ^ Glen Shires, Intel, Santa Clara, Ca. O O Usenet: {ucbvax!amd,pur-ee,hplabs}!intelca!glen > ARPA: "amd!intelca!glen"@BERKELEY \-/ --- stay mellow