Method, article, and apparatus for dynamic phase delay compensator

Abstract

An apparatus, method, and article to dynamically adjust a data signal using a regenerated clock signal in an emulator to increase communication speed between the emulator and the evaluation board is disclosed. In one embodiment, this is achieved by applying a reference clock signal at a predetermined frequency to a digital circuit. A delayed return data signal is then sampled from the digital circuit. The sampled delayed return data signal is then compared to an expected return data signal. The delayed return data signal is then adjusted as a function of the comparison to increase the communication speed between the emulator and the evaluation board.

1 - 12 . (canceled) 
   
   
       13 . A method of communicating between an emulator and an evaluation board including a digital circuit comprising:
 applying a reference clock signal to the digital circuit and a delayed reference clock generator contained in the emulator;   sampling a delayed return data signal from the digital circuit by the delayed reference clock generator;   comparing, by the delayed reference clock generator, the sampled delayed return data signal to an expected return data signal generated by the delayed reference clock generator;   if the delayed return data signal is equal to the expected return data signal, then using the applied reference clock signal in the digital circuit to communicate between the digital circuit and the emulator; and   if the delayed return data signal is not equal to the expected return data signal, then adjusting a delay in the delayed return data signal by varying a delay of the reference clock signal until the delayed return data signal is equal to the expected return data signal.   
   
   
       14 . The method of  claim 13 , wherein adjusting the delay in the delayed return data signal by varying the delay of the reference clock signal until the delayed return data signal is equal to the expected return data signal comprises:
 adjusting the reference clock signal using a predetermined amount of time;   applying the adjusted reference clock signal to the digital circuit and the delayed reference clock generator;   sampling the delayed return data signal from the digital circuit by the delayed reference clock generator;   comparing, by the delayed reference clock generator, the sampled delayed return data signal to the expected return data signal generated by the delayed reference clock generator;   if the delayed return data signal is equal to the expected return data signal, then using the applied reference clock signal in the digital circuit to communicate between the digital circuit and the emulator;   if the delayed return data signal is not equal to the expected return data signal, then computing a delay between the reference clock signal and the adjusted reference clock signal;   determining that the computed phase delay exceeds a threshold phase delay; if so, then adjusting the reference clock signal by decrementing the reference clock signal using the predetermined amount of time and using the adjusted reference clock signal to communicate between the emulator and the digital circuit; and   if not, then repeating the above adjusting, applying, sampling, comparing and determining steps until the delayed return data signal is equal to the expected return data signal and using the adjusted reference clock signal to communicate between the emulator and the digital circuit.   
   
   
       15 . The method of  claim 14 , wherein adjusting the reference clock signal using a predetermined amount of time comprises:
 initializing the reference clock signal to a zero delay;   adjusting the referenced clock signal by incrementing the initialized reference clock by about 250 picoseconds;   computing the delay between the reference clock signal and the adjusted reference clock signal;   comparing the computed phase delay to the threshold phase delay;   if the computed phase delay is greater than or equal to the threshold phase delay, then decrementing the reference clock signal by about 5 MHz; and   repeating the adjusting, comparing, and decrementing steps until the computed phase delay is equal to or greater than the threshold phase delay, if the computed phase delay is less than the threshold phase delay.   
   
   
       16 . The method of  claim 13 , wherein the digital circuit comprises components selected from the group comprising cables and connectors connecting between the emulator and the evaluation board, PC board circuitry, and buffers on the evaluation board. 
   
   
       17 . An article comprising:
 a storage medium having instructions that, when executed by a computing platform, result in execution of a method comprising:   applying a reference clock signal at a predetermined frequency to a digital circuit and a delayed reference clock generator contained in the emulator;   sampling a delayed return data signal from a digital circuit by the delayed reference clock generator;   comparing, by the delayed reference clock generator, the sampled delayed return data signal to an expected return data signal generated by the delayed reference clock generator;   if the delayed return data signal is equal to the expected return data signal, then using the applied reference clock signal in the digital circuit to communicate between the digital circuit and an emulator; and   if the delayed return data signal is not equal to the expected return data signal, then adjusting a delay in the delayed return data signal by varying a delay of the reference clock signal until the delayed return data signal is equal to the expected return data signal.   
   
   
       18 . The article of  claim 17 , wherein adjusting the delay in the delayed return data signal by varying the delay of the reference clock signal until the delayed return data signal is equal to the expected return data signal comprises:
 adjusting the reference clock signal using a predetermined amount of time;   applying the adjusted reference clock signal to the digital circuit and the delayed reference clock generator;   sampling the delayed return data signal from the digital circuit by the delayed reference clock generator;   comparing, by the delayed reference clock generator, the sampled delayed return data signal to the expected return data signal generated by the delayed reference clock generator;   if the delayed return data signal is equal to the expected return data signal, then using the applied reference clock signal in the digital circuit to communicate between the digital circuit and the emulator;   if the delayed return data signal is not equal to the expected return data signal, then computing a delay between the reference clock signal and the adjusted reference clock signal;   determining that the computed phase delay exceeds a threshold phase delay;   if so, then adjusting the reference clock signal by decrementing the reference clock signal using the predetermined amount of time and using the adjusted reference clock signal to communicate between the emulator and the digital circuit; and   if not, then repeating the above adjusting, applying, sampling, comparing and determining steps until the delayed return data signal is equal to the expected return data signal and using the adjusted reference clock signal to communicate between the emulator and the digital circuit.   
   
   
       19 . The article of  claim 18 , wherein adjusting the reference clock signal using a predetermined amount of time comprises:
 initializing the reference clock signal to a zero delay;   adjusting the referenced clock signal by incrementing the initialized reference clock by about 250 picoseconds;   computing the delay between the reference clock signal and the adjusted reference clock signal;   comparing the computed phase delay to the threshold phase delay;   if the computed phase delay is greater than or equal to the threshold phase delay, then decrementing the reference clock signal by 5 MHz; and   repeating the adjusting, comparing, and decrementing steps until the computed phase delay is equal to or greater than the threshold phase delay, if the computed phase delay is less than the threshold phase delay.   
   
   
       20 . The article of  claim 17 , wherein the digital circuit comprises components selected from the group comprising cables and connectors connecting between the emulator and an evaluation board, PC board circuitry, and buffers on the evaluation board. 
   
   
       21 . An apparatus, comprising:
 a digital circuit; and   an emulator coupled to the digital circuit, wherein the emulator further comprising:
 a reference clock generator that generates and applies a reference clock signal at a predetermined frequency to the digital circuit; 
 a sample block coupled to a delayed reference clock generator, wherein the sample block samples a delayed return data signal from the digital circuit, wherein the delayed reference clock generator determines whether the delayed return data signal is equal to an expected return data signal generated by the delayed reference clock generator; and 
 a serial protocol generator that uses the applied reference clock signal in the digital circuit to communicate between the digital circuit and the emulator, if the delayed return data signal is equal to the expected return data signal, and wherein the serial protocol generator adjusts a delay in the delayed return data signal by varying a delay of the reference clock signal until the delayed return data signal is equal to an expected return data signal, if the delayed return data signal is not equal to the expected return data signal. 
   
   
   
       22 . The apparatus of  claim 21 , wherein the serial protocol generator adjust the reference clock signal using a predetermined amount of time, wherein the serial protocol generator applies the adjusted reference clock signal to the digital circuit, wherein a sample block coupled to a delayed reference clock generator samples the delayed return data signal from the digital circuit, wherein the delayed reference clock generator compares the sampled delayed return data signal to the expected return data signal,
 wherein the serial protocol generator uses the applied reference clock signal, if the delayed return data signal is equal to the expected return data signal to communicate between the digital circuit and the emulator,   wherein the serial protocol generator computes a delay between the reference clock signal and the adjusted reference clock signal, if the delayed return data signal is not equal to the expected return data signal,   wherein the serial protocol generator determines whether the computed phase delay exceeds a threshold phase delay, wherein the serial protocol generator adjusts the reference clock signal by decrementing the reference clock signal using the predetermined amount of time and uses the adjusted reference clock signal, if the computed phase delay exceeds the threshold phase delay to communicated between the emulator and digital circuit, and   wherein the serial protocol generator repeats the adjusting of the reference clock signal until the delayed return data signal is equal to the expected data signal and uses the adjusted reference clock signal, if the computed phase delay does not exceed the threshold phase delay to communicate between the emulator and the digital circuit.   
   
   
       23 . The apparatus of  claim 22 , wherein the serial protocol generator initializes the reference clock signal to a zero delay, wherein the serial protocol generator adjusts the reference clock signal in increments of about 250 picoseconds, wherein the serial protocol generator compares the computed phase delay to the threshold phase delay, wherein serial protocol generator decrements the reference clock signal by 5 MHz, if the computed phase delay is greater than or equal to the threshold phase delay, and wherein the serial protocol generator repeats adjusting of the reference clock signal until the computed phase delay is equal to or greater than the threshold phase delay, if the computed phase delay is less than the threshold phase delay. 
   
   
       24 . The apparatus of  claim 21 , wherein the digital circuit comprises components selected from the group comprising cables and connectors connecting between the emulator and an evaluation board, PC board circuitry, and buffers on the evaluation board.