BIRD ID#: 14.3 ISSUE TITLE: Adding four new sub-parameters to [Model] REQUESTER: John Keifer at Intel DATE SUBMITTED: April 26, 1994 DATE REVISED: May 18, 1994, May 20, 1994 DATE ACCEPTED BY IBIS OPEN FORUM: May 20, 1994 (A portion of BIRD14.1, BIRD14.2 resubmitted as BIRD16) ************************************************************************* ************************************************************************* STATEMENT OF THE ISSUE: It is desirable to have four new sub-parameters added to a [Model] in order to fully represent the characteristics of a given component's I/O cells. These sub-parameters are desirable for the user of the IBIS [Models] who wishes to perform board level simulations. ************************************************************************* STATEMENT OF THE RESOLVED SPECIFICATIONS: Four new sub-parameters, Cref (a reference specload), Rref (a reference resistance), Vref (a reference voltage), and Vmeas (a test voltage), are added to a [Model]. These sub-parameters are also optional. The [Model] section should be changed as shown below, only changes are listed. |************************************************************************* | | Keyword: [Model] | . | . | Sub-Params: ..., Vmeas, Rref, Vref, Cref | | Other Notes: ... Component timings are usually specified into a | reference capacitance that can be listed as Cref, or into | a reference resistance, Rref, pulled to a reference voltage, | Vref. Vmeas is the test voltage at a driver that timings are | specified to. (This is usually around the 50% level of the | voltage thresholds. For example, TTL=1.5V, CMOS=2.5V.) | |************************************************************************* Example: [Model] IB080812 Model_type I/O Polarity Non-Inverting Enable Active-High | Signals A[2-17] Vinl = 0.8V Vinh = 2.0V Vmeas=1.5V |Test voltage timings are specified to Rref=NA |Reference resistance Vref=NA |Reference voltage Cref=50pF |Reference capacitance timings are specified into The Vmeas, Rref, Vref, and Cref sub-parameters would be placed inside each [Model] file, after Vinh. Pictorial description: _________ | | | |\ | Rref |Driver| \|------|----/\/\/----o Vref | | /| _|_ | |/ | --- Cref --------- | --- ************************************************************************* ANALYSIS PATH/DATA THAT LED TO SPECIFICATION: All of these added [Model] sub-parameters, Vmeas, Rref, Vref, and Cref are standard data available in data books. Allowing the specification of Vmeas, Rref, Vref, and Cref enhances the usability of an IBIS model by providing key parameters for simulation. ************************************************************************* ANY OTHER BACKGROUND INFORMATION: ************************************************************************* To IBIS Committee: The only real problems I have heard that anybody has with this Bird is that it will be difficult for simulation vendors to implement quickly, and that those just starting to make and use IBIS [Model]s might presently get confused with this new keyword. However, everyone, at the same time, seems to agree that this is a good Bird for those making and using IBIS [Model]s from the perspective of having a smaller .IBS file therefore making it quicker to create, more efficient, and using up less disk space. Am I correct in assuming that everyone would generally agree that this would be a good BIRD to pass for the next IBIS version, but IBIS version 2.0 is too soon? If this is true, this BIRD should just be held out until the final IBIS 2.0 is official, and then passed for the next IBIS version instead of getting thrown out completely. John Buffer Issue Resolution Document (BIRD) BIRD ID#: 16 ISSUE TITLE: Adding an override section for [Model] sub-parameters REQUESTER: John Keifer at Intel DATE SUBMITTED: May 23, 1994 DATE ACCEPTED BY IBIS OPEN FORUM: ************************************************************************* ************************************************************************* STATEMENT OF THE ISSUE: It is desirable to have a new optional keyword added to the top of an .IBS file in order to parameterize the sub-parameters of a [Model] so that each time a [Model] is used with a different sub-parameter a new [Model] would not have to be made. ************************************************************************* STATEMENT OF THE RESOLVED SPECIFICATIONS: A new keyword, [PIN EXTENSION 1], is added to the .IBS file. The keyword [PIN EXTENSION 1] and all of its sub-parameters are optional. The sub-parameters under this keyword override the sub-parameters of a [Model]. Only those pins should be listed in the [PIN EXTENSION 1] section which need to override the default sub-parameters of a [Model]. All sub-parameters must be filled in on a line either with NA or a value. |************************************************************************* | | Keyword: [PIN EXTENSION 1] | Required: No |Description: Used to list pin-level specifications that differ from | the more global sub-params listed under [Model] below. | Sub-Params: Vinl, Vinh, Vmeas, Rref, Vref, Cref, C_comp |Usage Rules: Only pins that have values different from the default | values specified in [Model] sub-parameters should be | listed. Sub-parameters not used on a line must be | filled in with NA. | The [PIN EXTENSION 1] section consists of five characters | for a pin number, six for Vinl, six for Vinh, six for Vmeas, | five for Rref, five for Vref, five for Cref, and six | for each of the three sub-parameters in C_comp. These | three sub-parameters represent the following: typ, min, | and max. All sub-parameters must be separated by at | least one blank space. This comes to a total of | sixty-six characters. | |************************************************************************* Example: Pin1 = I/O, Pin4 = Output/3-state, Pin9 = Input [PIN EXTENSION 1] | C_comp Pin Vinl Vinh Vmeas Rref Vref Cref typ min max 1 0.8V 2.0V 1.5V NA NA 50pF 4.5pF 3.0pF 6.0pF 4 NA NA 2.5V NA NA 30pF NA NA NA 9 1.5V 3.5V NA NA NA NA NA NA NA 12 NA NA NA NA NA NA NA NA NA 13 NA NA NA 50 5V NA NA NA NA This section will be placed directly underneath the pin list (the [Pin] keyword section). ************************************************************************* ANALYSIS PATH/DATA THAT LED TO SPECIFICATION: Presently if a particular [Model] needs to be used for a couple of buffers in which the only differences are in the Vinl, Vinh, or C_comp sub-parameters, separate [Model]s have to be made. With the [PIN EXTENSION 1] keyword, only one [Model] has to be made with the sub-parameters being passed down from the [PIN EXTENSION 1] section. This feature will reduce the size of the .IBS file. The [PIN EXTENSION 1] section allows separating the details from the core of a [Model], and at the same time, gives the user the sub-parameters he needs. The [PIN EXTENSION 1] keyword is also optional and hence fully backward compatible. ************************************************************************* ANY OTHER BACKGROUND INFORMATION: ************************************************************************* ------- End of Unsent Draft