🚀 go-pugleaf

On Fri, 30 Oct 2009 15:43:58 +0000, Raveninghorde
<raveninghorde@invalid> wrote:

>On Fri, 30 Oct 2009 06:52:49 -0700 (PDT), MooseFET
><kensmith@rahul.net> wrote:
>
>>On Oct 30, 4:57�am, Al Borowski <al.borow...@gmail.com> wrote:
>>> > 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.
>>
>>Going with accumulator model allowed Microchip to make the processor
>>with fewer transistors. It is a trade off that can break either way.
>>If you have a limit on the chip size you can make a higher performance
>>processor that is harder to program.
>>
>>
>>[....]
>>> 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 :-)
>>
>>Does ifbit mean skip if the bit is set or do the instruction if the
>>bit is set?
>>
>>>
>>> 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;
>>
>>I still prefer the 8051.  It is way better.
>>[ducks]
>
>So do I. The 8051 family was/is great. 
>
>But I found the varients of 8051 I used were obsolete on more than one
>occassion causing problems. I'm still sourcing SAB80C517 at silly
>prices for example.

8051s, in several performance varieties (parallel one-clock to the
original serial 12-clock ALU), are now available as FPGA soft cores.
Obsolete chip?  Just synthesize. Haven't quite figured out why I want
to buy FPGA fabric to do an 8051, though.  ;-)

>I first used the PIC for very low cost apps around 1990 and found that
>there was always an upgrade path which didn't obsolete my designs.
>
>Secondly Microchip always have product available.  I recall one rep
>trying to convert me to the ST6. Then he said ST are behind on
>production and delivery was 4-6 months.
>
>There are better micros than the PIC from an engineering perspective
>but they are hard to beat from a production view point.

I don't see much use for the larger PICs.  We're using a PIC-24 but
it's more than overkill and just too weird.