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- Path: sparky!uunet!spool.mu.edu!agate!doc.ic.ac.uk!uknet!acorn!melbourne!AWilliams
- From: AWilliams@melbourne.uucp (Alan Williams)
- Newsgroups: comp.sys.acorn.tech
- Subject: Re: Driving the Real Time Clock
- Message-ID: <224@melbourne.uucp>
- Date: 11 Nov 92 14:50:09 GMT
- References: <721308024.4228@minster.york.ac.uk>
- Sender: alan@melbourne.uucp
- Distribution: comp
- Organization: Acorn Computers Ltd, Cambridge, England
- Lines: 25
-
- In article <721308024.4228@minster.york.ac.uk> mhw@minster.york.ac.uk
- writes:
-
- >Can someone tell me the part number of the real time clock/non-volatile
- >RAM chip used in the A3xx and A4xx series machines and suggest where I
- >might be able to get hold of data sheets from? Are the same parts used
- >in the newer machines (i.e. A5000 and co.)?
-
- Its a PCF 8583 and it comes from Philips, at least the data book I have does.
- The whole IIC chipset fills two hefty volumes and includes some quite
- remarkable devices. It makes fascinating reading. I have done a bit of work
- driving IIC from my Model B if you ever want 6502 code to do it!
-
- I am interested by the suggestion made recently in this news group, that this chip
- may have a mode where it becomes an 'engine hours' counter rather than a RTC.
- I have a customer who is reporting exactly these symptoms for his machine I
- will be rather pleased if I can find a soft fix. Power on R sounds like a good
- start. I am going home to night to read the data book!
-
- I think that its the same chip in all machines ( except being in an smd pack these
- days) , the A4 loads a different IIC module so that may be the odd one out.
-
- Alan.
-
- The views expressed are my own and are not necessarily those of Acorn.
-