Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!uwm.edu!rpi!zaphod.mps.ohio-state.edu!mips!daver!bungi.com!news From: dlr@daver.bungi.com (Dave Rand) Newsgroups: comp.sys.nsc.32k Subject: Re: pc532 power use Message-ID: Date: 13 Jul 90 20:48:59 GMT Sender: news@daver.bungi.com Lines: 31 Approved: news@daver.bungi.com [In the message entitled "pc532 power use" on Jul 13, 13:40, Jon Buller writes:] > Just a couple of quick questions as my board nears completion. Can > +5V be applied without +12 and -12? Yes - although you must connect the +/-12 before trying to use the board with a terminal. These voltages power only the 145406's (RS232 level shifters). > And about how much current does > it draw? It must be less than 2A, but that seems like a lot to me. The board running at 25 Mhz draws about 2.5 Amps of +5 (2.1 if you are using 2692 CMOS DUARTs). The +/-12 V supply only requires a few milliamps. Note that some switching power supplies will refuse to come up without additional load on the +12V rail - such as a disk drive. A typical IBM AT style power supply provides 20 to 25 Amps of +5, and 10 Amps or so of +12. -12 is usually 500 mA. Besides 2.5 A is about 12.5 watts - not back for a 12 MIPS machine! > And one other thing, does the monitor speak on any port that it gets > some data, or on connector 3 first (or some other arrangement, and what > speed too)? The monitor will talk on CONN3. Be sure to have _ALL_ of the DUARTs installed (or at least U60), as the 3.6864 Mhz clock is shared between all of the DUARTs. -- Dave Rand {pyramid|mips|sun|vsi1}!daver!dlr Internet: dlr@daver.bungi.com