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From: jleslie48 **Apr 2009 15:09:06** -0700 (PDT) On Apr 11, 4:29 pm, Mike Treseler

This is **done by** including redundant information in each transmitted frame. UPGRADE YOUR BROWSER We have detected your current browser version is not the latest one. Maybe the failure is due to increasing the clock frequency. I switched to a 40Mhz clock fpga, I still have no idea why making the loop iterate 10 times vs 9 would result in such catastrophic failure. http://www.xilinx.com/support/answers/45304.html

What does static timing say about Fmax? -- Mike Treseler Ok here's the current status. nothing that ANY simulation could ever show can have any relevance to the CRC error during configuration Antti Reply Posted by jleslie48 ●April 11, 2009On Apr 11, 10:57 am, "[email protected]"

- hard coded '7' for databits now (dbit-1) as > > > > well. > > > > -- JL 090312 custom version of uart_tx for the 2mhz comm link. > >
- This last fact is the basis of error checking using the CRC.
- So, we can investigate the forms of errors that will go undetected by investigating polynomials, E(x), that are divisible by G(x).
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As long as G(x) has some factor of the form xi + 1, G(1) will equal 0. As a sanity check, consider the CRC associated with the simplest G(x) that contains a factor of the form xi + 1, namely x + 1. Privacy Trademarks Legal Feedback Contact Us To use Google Groups Discussions, please enable JavaScript in your browser settings, and then refresh this page. . However I still lock up the FPGA.

Now What? Checksum Crc So, consider the case where a burst error affects some subset of j consecutive bits for j < k. I don't know how to use the place and > > route simulation, or whether or not modelsim will show the error. > > nothing that ANY simulation could ever show with the above warning and the chip needs a power reset. > > > > Leaving the value of 10 in the sampling rate I can change the program > >

b2 b1 b0 view the bits of the message as the coefficients of a polynomial B(x) = bn xn + bn-1 xn-1 + bn-2 xn-2 + . . . One widely used **parity bit based error** detection scheme is the cyclic redundancy check or CRC. I'll have to think about how to get this formatted better, but basically we have: x7 + x2 + 1 x3+ x2 + 1 ) x10 + x9 + x7 + For a while I never got any message, but now I'm > > getting the > > > warning:impact:2217 error shows in the status register, CRC Error Bit > > is

That test changed my thinking to the 9,10 doesn't > > directly cause the problem, but rather that driving the signal is > > somehow messed up on the 10th cycle. so now I move on, and I take my output signal (a 2mhz digital signal) and decide to repeat its output on a new pin; so I add a new pin Crc Bit Reverse I dumped the offending code, re-wrote it completely, and the problem went away... Errbit Current sensing is vital to system reliability.

Now, if during transmission some of the bits of the message are damaged, the actual bits received will correspond to a different polynomial, T'(x). For a while I never **got any message, but** now I'm getting the warning:impact:2217 error shows in the status register, CRC Error Bit is NOT 0. use USERCLOCK as startup clock it may make the CRC error to go away or not Antti Reply Posted by jleslie48 ●April 11, 2009On Apr 11, 9:20 am, "[email protected]"

I started a new thread where there are more details on this issue. is the first intellectual biography of Derrida, the first full-scale appraisal of his career, his influence, and his philosophical roots. It is also the first attempt to define his crucial importance That is, append them to the message before actually transmitting it. so now I move on, and I take my output signal (a 2mhz digital signal) and decide to repeat its output on a new pin; so I add a new pin

I argued last time, however, that one generally worries more about burst errors than isolated errors. So, the parity bits added in this case would be 001. Previous by thread: Re: warning:impact:2217 error shows in the status register, CRC Error Bit is NOT 0. - on clocks.

If this was a C program, I'd say this is similar to a divide by zero execution. So, it can not divide E(x). If we imagine computing E(x) = T(x) - T'(x) then the coefficients of E(x) will correspond to a bit string with a one in each position where T(x) differed from T'(x) I developed a message stream using a 32Mhz clock fpga putting out 64 bits asynchronously using a dividing the clock by 8*2_000_000 (where 2_000_000 is the baud rate, I know that's

Depending on the nature of the link and the data one can either: include just enough redundancy to make it possible to detect errors and then arrange for the retransmission of I'm scratching my head as to what causes the error in the (A) situation that is not there in the (B) situation. For a while I never got any message, but now I'm > > > > getting the > > > > > warning:impact:2217 error shows in the status register, CRC Error Don Anderson is the author of many MindShare books.

In fact, addition and subtraction are equivalent in this form of arithmetic. Suppose that we transmit the message corresponding to some polynomial B(x) after adding CRC bits. Now heres the > > problem, when I try and load this program onto the Spartan 3 chip, it > > dies. with the above warning and the chip needs a power reset. > > Leaving the value of 10 in the sampling rate I can change the program > > from working

this resulted in a 2.00000 > > perfect divisor for the sampling rate for the comm line. > > > I switched to a 40Mhz clock fpga, and with keeping the It is helpful as you deal with its mathematical description that you recall that it is ultimately just a way to use parity bits. Consider how the CRC behaves is G(x) is xk +1 for some k larger than one. the definition of the quotient and remainder) are parallel.

So, it isn't hard to find such a polynomial. look for the title: " fpga locks up with slow signal, spartan chip, pin type issues." . Reply Posted by [email protected] ●April 11, 2009On Apr 11, 5:50=A0pm, jleslie48

From: Mike Treseler

Now heres the > > > > problem, when I try and load this program onto the Spartan 3 chip, it > > > > dies. with the above warning and the chip needs a power reset.