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Article #669Re: My hat is off to Microchip and their CEO!
From: Al Borowski
Date: Fri, 30 Oct 2009 11:57
Date: Fri, 30 Oct 2009 11:57
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2754 bytes
> Briefly, the Modified-Harvard architecture used in the PIC devices > separates the program memory from the data memory, in other words > separates the ROM/FLASH program memory from the RAM. [...] Yes, but there's more to to a uC core then choosing between Harvard or Von Neumann. I think most of the PICs quirks come from the other decisions made. The PIC (up to 16 bit cores anyway) is an accumulator architecture - you have to funnel everything through the W register. AVRs for instance have 32 registers which is nowhere near as clunky. The PIC has dedicated memory for the Stack and is a PITA to save/restore local variables. PICs have fun issues with banking and paging (not so much in the 16 bit core thankfully). Personally, I think the most annoying thing about programming PICs in assembly are the btfsc (test a bit in 'file', skip the next instruction if it's clear) and btfss (same thing but skip if set) instructions. Why they couldn't just call these ifbit and ifnbit, I don't know :-) Back to the OP, great job Microchip on the video. It's a nice contrast to TI, who recently sent misleading DMCA notices to people who tried installing after-market OSs on their graphics calculators ( http://news.cnet.com/8301-30685_3-10374284-264.html ) Cheers, A;
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X-Google-Thread: a5a6238865,3efb481b0f84bbd4 X-Google-Attributes: gida5a6238865,public,usenet X-Google-NewGroupId: yes X-Google-Language: ENGLISH,ASCII-7-bit Path: arc1-ca.pugleaf.net!g2news2.google.com!postnews.google.com!g22g2000prf.googlegroups.com!not-for-mail From: Al Borowski <al.borowski@gmail.com> Newsgroups: sci.electronics.design,aus.electronics Subject: Re: My hat is off to Microchip and their CEO! Date: Fri, 30 Oct 2009 04:57:29 -0700 (PDT) Organization: http://groups.google.com Lines: 33 Message-ID: <d1f9f3c6-0d75-429d-9c19-6d23b72b7997@g22g2000prf.googlegroups.com> References: <a7nGm.354$hJ2.98@newsfe13.iad> <74a52943-f086-451d-bb24-99783529b1bc@d5g2000yqm.googlegroups.com> <72uGm.50908$ze1.32966@news-server.bigpond.net.au> <_NSdndVPsfmd83fXnZ2dnUVZ_sudnZ2d@westnet.com.au> <G1vGm.50913$ze1.9795@news-server.bigpond.net.au> NNTP-Posting-Host: 123.243.237.83 Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 X-Trace: posting.google.com 1256903850 1610 127.0.0.1 (30 Oct 2009 11:57:30 GMT) X-Complaints-To: groups-abuse@google.com NNTP-Posting-Date: Fri, 30 Oct 2009 11:57:30 +0000 (UTC) Complaints-To: groups-abuse@google.com Injection-Info: g22g2000prf.googlegroups.com; posting-host=123.243.237.83; posting-account=5H4S7goAAACAnc69KWfuDSHJrozAlaBU User-Agent: G2/1.0 X-HTTP-UserAgent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-GB; rv:1.9.0.6) Gecko/2009011913 Firefox/3.0.6,gzip(gfe),gzip(gfe)