Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!utgpu!water!watmath!watdcsu!magore From: magore@watdcsu.UUCP Newsgroups: rec.audio,sci.electronics Subject: Re: "Remote Controller" Sony ... make your own Message-ID: <3935@watdcsu.waterloo.edu> Date: Thu, 8-Oct-87 15:42:55 EDT Article-I.D.: watdcsu.3935 Posted: Thu Oct 8 15:42:55 1987 Date-Received: Sun, 11-Oct-87 05:29:12 EDT References: <14770@linus.UUCP> <2152@ihlpe.ATT.COM> Reply-To: magore@watdcsu.waterloo.edu (Mike Gore, Institute Computer Research - ICR) Organization: U. of Waterloo, Ontario Lines: 50 Xref: utgpu rec.audio:3054 sci.electronics:1346 Summary: Making your own Hello Peter, In article <2152@ihlpe.ATT.COM> psfales@ihlpe.ATT.COM (Pete Fales) writes: [munch...] >Do you really need to know the signal format? I recently built a >mult-device IR controller (similar to the one recently described in Byte >magazine). No need to decode the format, just digitally "record" a >sample of the signal and play it back. The Byte article describes >the tricks to reducing this to a manageable volume of data. [munch...] >Peter Fales UUCP: ...ihnp4!ihlpe!psfales I have a few comments about the Byte article. The Byte article used a PC via serial interface to the 8031 for initial set-up of menus and such. If you drop the serial interface and have the controler do all the work you can use the internal shift register to sample at up to 1.25MHZ [ with 15Mhz version ] - thus dropping the need for an external shifter as in the article. I find that the 8031 has no problem generating the codes for my SONY VCR _without_ the external hardware timers used... This is obvious, the timings can only be as good as the original sample rate and the 8031 can surely put out at the same rate it samples in the first place! Using the internal 8 bit shifter mode is not really needed for output though. Most instructions take 12 clocks and this includes port bit invert instructions so an inline section of code can actually 'bit-bang' at 1MHZ or better depending on clock. As Peter implied if you want to save memory space by say storing just the time between transitions. Durring play back you can reconstruct the original bit stream and then play it back -or you can reconstruct the timings on the fly. In the latter case to avoid hard coding delay loops all one has to do is generate the delay code in place in RAM and branch to it ! [I know - ugh] This requires connecting (PSEN & RD) ] - So you then have self generating code which is a timing win over branch delays which are 24 clocks. With regards to Peters comment about just needing to sample store: The Byte article 'cheated' by _assuming_ a carrier coded data stream to save more space then the methods suggested here. Still I think if someone just samples and then use edge transition time compression alone I think they could get quite enough starage with only a few 32K CMOS RAMS for several remotes. Add to edge transition run-length compression of the edge data itself and you have something just as good as the Byte version but with far less wired in assumptions or complexity - which of course is what Peter is saying... Another point - the 8031 is also made in CMOS... Best Regards, # Mike Gore # Institute for Computer Research. ( watmath!mgvax!root - at home ) # These ideas/concepts do not imply views held by the University of Waterloo.