****************************************************************************** ********************* IBIS GOLDEN PARSER BUG REPORT FORM ********************* ****************************************************************************** INSTRUCTIONS To report a bug in the IBIS golden parser. Please fill out the top part of the following form and send the complete form to ibischk-bug@vhdl.org. A list of reported bugs will be maintained on vhdl.org. ****************************************************************************** PARSER VERSION NUMBER: 3.2.6 PLATFORM (SPARC, HP700, PC, etc.): PC OS AND VERSION: Windows 2000 REPORTED BY: Michael Mirmak, Intel Corp. DATE: February 23, 2001 DESCRIPTION OF BUG: Section 6 of the IBIS specification states, under the [Pulldown], [Pullup], [GND Clamp] and [Power Clamp] description: "All four [voltage and current data] columns are required under these keywords. However, data is only required in the typical column. If minimum and/or maximum current values are not available, the reserved word 'NA' must be used." Allowing the reserved word "NA" to represent "no data" in the V-I curves of an IBIS model means a model can contain no data whatsoever for the min and max corner V-I sections. For some types of models, the parser still attempts to read and check the drive capability of V-I corners where V-I data is entirely missing, replaced by "NA" keywords. Warnings are generated, telling the user that the buffer is incapable of driving the Rref-to-Vref load through the specified Vmeas value for the missing corners. Note that this problem only occurs for models missing a [Pullup] section. The use of different Model_type keywords does not appear to affect the generation of incorrect warnings. No such warnings should be generated for models where the V-I data has been entirely removed for either the min or max corner. This bug applies to both parser v3.2.5 and v3.2.6. INSERT IBIS FILE DEMONSTRATING THE BUG: |*********************************************************************** | [IBIS Ver] 3.2 [File Name] bug54.ibs [File Rev] 0.0 [Date] 22-February-2001 [Source] File created from specification [Notes] Using the IBISCHK3 v3.2.5 & v3.2.6 parsers, the following file will show two misleading warnings related to the buffer delay fixture. | [Disclaimer] (C) Copyright 2001 Intel Corp. All rights reserved This model is for demonstration purposes only, | [Component] GENERIC_IBIS [Manufacturer] Intel Corp. | [Package] | typ min max R_pkg 6.0mO 5.0mO 7.0mO L_pkg 5.0nH 2.0nH 8.0nH C_pkg 1.0pF 0.5pF 1.5pF | | [Pin] signal_name model_name R_pin L_pin C_pin 1 TestSignal1 TestModel1 | |************************************************************************ | [Model] TestModel1 Model_type I/O_open_sink |Model_type I/O Polarity Non-Inverting Enable Active-Low | Vinl = 800mV Vinh = 2.0V | Cref = 0F Rref = 25ohms Vref = 5.0V Vmeas = 2.5V | C_comp 5.00pF 4.00pF 6.00pF | | [Temperature Range] 27.00 100.00 0.00 [Voltage Range] 5.0V 4.75V 5.25V | |[Pullup] || voltage I(typ) I(min) I(max) || | -5.0000 0.0m NA NA | -4.0000 0.0m NA NA | 0.0000 0.0m NA NA | 5.0000 0.0m NA NA | 10.0000 0.0m NA NA | | [Pulldown] | voltage I(typ) I(min) I(max) | -5.0000 -40.0m NA NA -4.0000 -39.0m NA NA 0.0000 0.0m NA NA 5.0000 200m NA NA 10.0000 400m NA NA | | [GND Clamp] | voltage I(typ) I(min) I(max) | -5.0000 -3900.0mA NA NA -0.7000 -80.0m NA NA -0.6000 -22.0m NA NA -0.5000 -2.4m NA NA -0.4000 0.0A NA NA 5.0000 0.0A NA NA | [Power Clamp] | voltage I(typ) I(min) I(max) | -5.0000 4450.00m NA NA -0.7000 95.0m NA NA -0.6000 23.0m NA NA -0.5000 2.4m NA NA -0.4000 0.0m NA NA 0.0000 0.0m NA NA | [Ramp] |variable typ min max dV/dt_r 2.20/1.06n 1.92/1.28n 2.49/650p dV/dt_f 2.46/1.21n 2.21/1.54n 2.70/770p R_load = 300ohms | | |************************************************************************ [End] | | The 3.2.6 parser gives the following spurious output: | |IBISCHK3 V3.2.6 | |Checking bug54.ibs for IBIS 3.2 Compatibility... | |WARNING - Model 'TestModel1': MIN VI curves cannot drive through Vmeas=2.5V | given load Rref=25 Ohms to Vref=5V |WARNING - Model 'TestModel1': MAX VI curves cannot drive through Vmeas=2.5V | given load Rref=25 Ohms to Vref=5V |WARNING - [Model] TestModel1 has no description of the buffer's high state | DC drive characteristics (no [Pullup] table). This warning | can be silenced by changing the Model_type or by adding a | [Pullup] table. | |Errors : 0 |Warnings: 3 | |File Passed | |Note that the third warning above is a separate issue, addressed in BUG53. | |Un-commenting the [Pullup] section results in the following output: | |IBISCHK3 V3.2.6 | |Checking bug54.ibs for IBIS 3.2 Compatibility... | |Errors : 0 | |File Passed | |Changing the Model_type to I/O has no effect. | ****************************************************************************** ******************** BELOW FOR ADMINISTRATION AND TRACKING ******************* ****************************************************************************** BUG NUMBER: 54 SEVERITY: [FATAL, SEVERE, MODERATE, ANNOYING, ENHANCEMENT] ANNOYING PRIORITY: [HIGH, MEDIUM, LOW] LOW STATUS: [OPEN, CLOSED, WILL NOT FIX, NOT A BUG] CLOSED FIXED VERSION: Version 3.2.8 FIXED DATE: November 20, 2001 NOTES ON BUG FIX: Classified at the March 2, 2001 IBIS Meeting. The example did not have all min and max column entries as NA, so this test is needed. If and how to fix this may depend on what combinations of NA information are considered sufficient. Discussed at the April 20, 2001 IBIS Meeting. The consensus was to fix this bug. It was clarified that the main problem to be fixed was to eliminate the false Warning messages when the [Pullup] table with 0 ma entries was not included. BUG54 may not deal with the general problem of deciding when NA entries mean no entries. ****************************************************************************** ******************************************************************************