If I understand Kumar correctly a clock_times returned by the getWave call can take on 3 possible meanings
* # # # # # # # -1 o Indicates sample points with a final point ...
* a single value of -1
o Indicates that the clock is not yet valid for a sampled receiver
* a single value of -1
o Indicates that the clock is not valid for a non-sampled receiver
An interesting problem for the EDA tool is that there is no way to
distinguish between a model where the clock is not yet locked, or a
model that does not have a CDR clock whatsoever. A fundamental
assumption of the IBIS-AMI spec is that the receiver does contain a
clock recovery circuit.
Another question, what meaning, if any, does clock_times in a getwave call have for a transmitter?
Scott -- Scott McMorrow Teraspeed Consulting Group LLC 121 North River Drive Narragansett, RI 02882 (401) 284-1827 Business (401) 284-1840 Fax http://www.teraspeed.com Teraspeed® is the registered service mark of Teraspeed Consulting Group LLC I think that Muranyi, Arpad wrote:
Kumar,So are you saying that the vector can beginwith a bunch of -1 and then have valid number later in the vector? Lie this:-1 -1 -1 -1 # # # # # # # # -1 -1 -1 -1 If this is true, is it also true that you canhave alternating -1 and good values in the vector? Like this?-1 -1 -1 -1 # # # # # # # # -1 -1 -1 -1 -1 -1 -1 -1 # # # # # # # # -1 -1 -1 -1 Arpad============================================== ------------------------------------------------------------------------ *From:* C. Kumar [mailto:kumarchi@xxxxxxxxx] *Sent:* Friday, March 26, 2010 3:29 PM *To:* Muranyi, Arpad *Subject:* Re: [ibis-macro] Question on clock_times arpad: let me take shot at this 1. Yes -1 indicates end of clock vector2. clock vector is the clocks associated with the particular wave vector in the particular getwave call.3. some models can have delayed start for returning a clock vector.Once a legitimate clock vector is returned , the eda tool is expected to use that information to sample the wave returned by the getwave call. Other wise the eda tool may rely on its own devices to sample the wave, (usually this is an 'ideal' clock)4. some models may modify the wave form but may never return a clock vector. (i.e -1 in the first position)------------------------------------------------------------------------ *From:* "Muranyi, Arpad" <Arpad_Muranyi@xxxxxxxxxx> *To:* ibis-macro@xxxxxxxxxxxxx *Sent:* Fri, March 26, 2010 4:08:16 PM *Subject:* [ibis-macro] Question on clock_times Hello AMI experts, I would like to ask a question about the clock_times vector. The spec says that "The last clock in indicated by putting a value of -1 at the and of clocks for the current wave sample". We got a DLL from a vendor which seems to fill the vector for the first few GetWave calls with -1 and then it starts filling it with good numbers. What is the interpretation of the specification? First, does the above text refer to the entire vector, or each little section independently that a single GetWave call returns? If it is for the entire vector, then having -1 in the first few thousand locations would mean that everything else after that is garbage, correct? If it is per GetWave call, is the EDA tool expected to assemble something from bits and pieces that are returned by the various GetWave calls? Thanks, Arpad =============================================================== --------------------------------------------------------------------- IBIS Macro website : http://www.eda.org/pub/ibis/macromodel_wip/ IBIS Macro reflector: //www.freelists.org/list/ibis-macro To unsubscribe send an email:To: ibis-macro-request@xxxxxxxxxxxxx <mailto:ibis-macro-request@xxxxxxxxxxxxx>Subject: unsubscribe
-- Scott McMorrow Teraspeed Consulting Group LLC 121 North River Drive Narragansett, RI 02882 (401) 284-1827 Business (401) 284-1840 Fax http://www.teraspeed.com Teraspeed® is the registered service mark of Teraspeed Consulting Group LLC
