Computer program and apparatus for evaluating signal propagation delays
AssigneeFujitsu Semiconductor Limited
InventorMitsuru Onodera
Life of this patent
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Abstract
A computer executes a signal delay evaluation program to determine whether reference levels used to define slew rates of a first circuit block are different from those used for a second circuit block that receives an output signal from the first circuit block. The computer corrects an output slew rate of the output signal supplied from the first circuit block to the second circuit block, based on a difference in the reference levels that is found between the first and second circuit blocks.
Claims14
A non-transitory computer-readable storage medium storing a computer program for evaluating signal propagation delays in an electronic device including a plurality of circuit blocks, the computer program, when executed on a computer, causing the computer to perform a method comprising:
- determining whether first reference voltage levels used to define a first output slew rate of an output signal supplied from a first circuit block is different from second reference voltage levels used to define an input slew rate of an input signal supplied to a second circuit block from the first circuit block, the first reference voltage levels comprising a first start threshold voltage level and a first end threshold voltage level to determine a start point and an end point, respectively, of rising or falling edges of the output signal, the second reference voltage levels comprising a second start threshold voltage level and a second end threshold voltage level to determine a start point and an end point, respectively, of rising or falling edges of the input signal;
- and
- correcting the first output slew rate based on slew rate errors corresponding to the differences between the first reference voltage levels and the second reference voltage levels, wherein:
- the first start threshold voltage level and the first end threshold voltage level are higher than a minimum voltage level of the output signal and are lower than a maximum voltage level of the output signal;
- and
- the second start threshold voltage level and the second end threshold voltage level are higher than a minimum voltage level of the input signal and are lower than a maximum voltage level of the input signal.
A non-transitory computer-readable storage medium storing a computer program for evaluating signal propagation delays in an electronic device including a plurality of circuit blocks, the computer program, when executed on a computer, causing the computer to execute a method comprising:
- determining whether a first reference voltage level used to define terminal-to-terminal delay data of cells in a first circuit block are different from a second reference voltage level used to define terminal-to-terminal delay data of cells in a second circuit block that receives an output signal from the first circuit block;
- and
- calculating an error of the terminal-to-terminal delay data of cells based on the difference between the first reference voltage level and the second reference voltage level and outputting that error as a terminal-to-terminal delay correction value.
An apparatus for evaluating signal propagation delays in an electronic device including a plurality of circuit blocks, the apparatus comprising:
- a platform discriminator to determine whether first reference voltage levels used to define an output slew rate of an output signal supplied from a first circuit block is different from second reference voltage levels used to define an input slew rate of an input signal supplied to a second circuit block from the first circuit block, the first reference voltage levels comprising a first start threshold voltage level and a first end threshold voltage level to determine a start point and an end point, respectively, of rising or falling edges of the output signal, the second reference voltage levels comprising a second start threshold voltage level and a second end threshold voltage level to determine a start point and an end point, respectively, of rising or falling edges of the input signal;
- and
- a slew rate corrector to correct the output slew rate based on the difference between the first reference voltage levels and the second reference voltage levels, wherein:
- the first start threshold voltage level and the first end threshold voltage level are higher than a minimum voltage level of the output signal and are lower than a maximum voltage level of the output signal;
- and
- the second start threshold voltage level and the second end threshold voltage level are higher than a minimum voltage level of the input signal and are lower than a maximum voltage level of the input signal.
Dependencies are inferred from the claim text.