Re: FPGA for PCI based servo control board

[Jon Elson <elson-at-pico-systems.com>]

John Sheahan wrote:

>On Fri, Apr 04, 2003 at 08:52:03AM -0500, jmkasunich-at-ra.rockwell.com wrote:
>  
>
>>NO. Raw packets.  Point-to-point connection, no
>>switches, hubs, or collisions.  Still need protection
>>against noise corrupted packets (CRC errors).
>>    
>>
>
>Agree.  8019 class devices do crc. 
>
>now the question of what happens when a packet is lost 
>arises.  Its equivilant to what happens when the 
>parallel port (choose favourite interface) glitches.
>(this is the root cause of my parallel port phobia)
>  
>
Well, why do you think the parallel port glitches?  I have run tests for 
hours
writing pseudo-random data into registers on my boards and the reading 
it back,
and checking for errors.  I haven't seen ANY errors, ever, on properly 
running
boards.

And, you should not have errors on a 2-node ethernet in a master/slave 
operation.
Really, the only errors are when more than one node tries to send at the 
same
time.

Jon