Thread View: comp.sys.acorn.tech
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Started by Mark D Smith
Sun, 08 Nov 1992 12:50
Re: real time and IIC
Author: Mark D Smith
Date: Sun, 08 Nov 1992 12:50
Date: Sun, 08 Nov 1992 12:50
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In article <1992Nov5.192740.23514@cs.nott.ac.uk> Simon Burrows writes: >In article <Bx8x68.3ID@dcs.ed.ac.uk> gst@dcs.ed.ac.uk (George Taylor) writes: >>I would have thought that the newer machines might not suffer from this >>problem. An A3010 in Dixons suffered more severe symptoms though I didn't >>have the operrtunity to look at it in detail. > >Why didn't you get the opportunity? Were you chucked out of the shop for >damaging one of their computers..? Doesn't sound a good idea. This sounds a rather odd problem, why should the RTC only stop counting when it is being powered from the battery rather than the mains? Obviously, there is still battery power to the RTC, otherwise it would lose the time completely (possibly be reset to Jan 1st 1990). Sounds to me like it is something that has been purposely built in to the RTC chip for some reason, and that there must be some way (using IIC_Control) of restoring normal operation, possibly to keep a record of the total length of time a machine has been in use? Obviously this 'function' is not intended to be used on the Arc. But why should the effect be 'more severe' on an A3010? (I assume the same RTC hardware is used) -- ------------------------------------------------------------------------------- | M M AAA RRRR K K Janet email: ee91mds2@brunel.ac.uk | | MM MM A A R R K K Subject: Microelectronic Systems Design | | M MM M AAAAA RRRR KK Establishment: Brunel University, U.K. | | M M A A R R K K | | M M A A R RR K K |
Re: real time and IIC
Author: Professor Coypu
Date: Thu, 12 Nov 1992 16:35
Date: Thu, 12 Nov 1992 16:35
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In an earlier article ee91mds2@brunel.ac.uk (Mark D Smith) writes: >This sounds a rather odd problem, why should the RTC only stop counting when >it is being powered from the battery rather than the mains? The Arc reads the RTC when it powers up, but for speed it keeps a software copy of the clock in memory while it is turned on. So the clock could have `seized up' at a certain figure and this figure would be read at each power on, but counted forwards normally from then on under interrupt control. (What I think I mean is that *every* time the machine reboots it would start counting from the same point) Alun. -- +-------------------------------------------------------------------+ | Alun Jones, Computer Science Dept. | Email : auj@uk.ac.aber | | U.W. Aberystwyth, Wales | GW1URF (Packet coming soon!) | +--Hi, I'm a signature Virus :-) Copy me into your sig to join in.--+
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