[Coco] FPGA VS Software Emulators

[Dave Philipsen]

Actually I believe that the CoCo3FPGA uses SRAM @ 10ns access time. I'm 
not 100% sure on this but I believe the CoCo on a chip is based upon the 
DE0 Nano which does not have SRAM but uses SDRAM instead.

Dave

On 7/25/2017 8:50 AM, Bill Nobel wrote:
> Hi Walter good points to bring up.
>
> The Coco on a chip project uses SRAM @ 10ns access time. The CocoFPGA uses a faster SRAM which is why the speed difference.  The reason software emulators can do a lot better speed is just that. Its a Software emulation, no speed limitations as it is a software clock that is changeable based on the CPU it’s being run on.  FPGA’s still have to communicate to real hardware which will pass a limitation to the speeds they run, depending on what is being interfaced. Each hardware device will have a different speed rating.  Both FPGA projects run on an internal clock of 50mhz which is then divided down to to a speed for each device connected (whether it’s internally programmed or physically attached).
>
> There are many other factors that affect speeds as well, but in this case the FPGA is not really the limitation, it’s the hardware that attaches to it.
>
> Bill Nobel
> b_nobel at hotmail.com<mailto:b_nobel at hotmail.com>
>
>
>
> On Jul 25, 2017, at 1:02 AM, Walter Zambotti <zambotti at iinet.net.au<mailto:zambotti at iinet.net.au>> wrote:
>
> Before I start this is not a one is better than the other debate.
>
>
>
> This is about better understanding each technology.
>
>
>
> Ok so my initial thoughts regarding FPGA (as I really know nothing) were
> hardware simulation should
> provide an end product that is more efficient and faster than a general
> CPU/software emulator.
>
>
>
> However this does not appear to be the case.
>
>
>
> The CoCo on a chip project emulates an 8mhz CoCo.
>
> The CoCoFPGA project a 25mhz CoCo.
>
> And VCC on my i5 (3.3 ghz) a 133mhz CoCo.
>
>
>
> What causes these differences in end speed?
>
>
>
> Why are the two FPGA projects so different in speed?
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>
>
> Why are both FPGA solutions slower than a CPU/software solution?
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>
>
> Is it the particular FPGA hardware itself?
>
>
>
> Would high end FPGAs provide a different result?
>
>
>
> I've just download the FPGA for Dummies eBook from Altera so I'm starting my
> education process.
>
>
>
> Walter
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>
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