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temtronic
Joined: 01 Jul 2010
Posts: 9633
Location: Greensville,Ontario
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 Posted: Mon Jun 22, 2015 7:06 am |
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hmm.. well their goes 'early retirement' for someone ! No sense in reinventing the wheel about a PIC FPU then..
One of those 'sounds good' ideas that just isn't a money maker.
Jay |
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Ttelmah
Joined: 11 Mar 2010
Posts: 20061
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| Posted: Mon Jun 22, 2015 9:02 am |
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| RF_Developer wrote: | | temtronic wrote: | | I assume using SPI as the interface so that every PIC could use it. |
SPI and I2C FPUs already exist, such as the Micromega uM-FPU V3.1. Apparently they aren't particularly popular or well-known. The problem with these is mainly the interface. FP co-processors get a lot of their speed by being tightly integrated with the main processor. SPI or I2C gives far looser coupling with much higher overheads, making the performance gains much less. |
However with something like a DsPIC, using DMA, the transfers can be handled without involving the actual CPU.
This FPU, is actually a dsPIC30F3012, with a FP library.....
Rather makes the point about using another PIC!..... |
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drolleman
Joined: 03 Feb 2011
Posts: 116
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| Posted: Mon Jun 22, 2015 9:18 am |
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External processing of data has very limited performance gains as the older 286 days proved. the co-processor must be internal. When the Pentium chip came out its claim to fame was pipelines. Then they went to multicores. the biggest gains of these chips is in server applications. Because the tools are not very good.
The biggest problem with multicore applications is the compiler and then debugging them. I have had to build a application to debug windows multithread applications because native debugging is horrible on all compilers / ide. I then ported some of this into my pic os. I usually overbuild my first prototype to accommodate debugging the new project. having in-house pcb manufacturing, makes one-of boards is quick and easy. Then down sizing as the development continues, I can minimize component count as project moves along. Even small projects will have 5 boards, before it goes to production.
david |
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