Dynamic timing adjustment in a circuit device
View Patent ↗A method includes determining a first operational characteristic representative of an operational speed of a circuit device at a first time. The method further includes receiving an input signal at an input of a first latch of the circuit device and receiving an output signal at an input of a second latch of the circuit device. The method additionally includes delaying a clock signal by a first delay to provide a first adjusted clock signal and delaying the clock signal by a second delay to provide a second adjusted clock signal. In one embodiment, the first delay and the second delay are based on the first operational characteristic. The method further includes latching the input signal at the first latch responsive to the first adjusted clock signal and latching the output signal at the second latch responsive to the second adjusted clock signal.
1. A method comprising:
providing a bus interface coupled to a processing unit and coupled to a memory and at least one peripheral device via a bus, the bus interface comprising a first latch, a second latch, and a first logic, the first latch receiving a first signal and providing a first latched signal, the second latch receiving a second signal and providing a second latched signal, and the first logic receiving the first latched signal from the first latch and providing the second signal to the second latch;
determining an operational characteristic representative of an operational speed of the bus interface;
adjusting a latency of a first clock signal that controls a timing of the first latch based on the operational characteristic; and
adjusting a latency of a second clock signal that controls a timing of the second latch based on the operational characteristic.
2. The method of claim 1 , wherein determining the operational characteristic comprises:
generating a third clock signal via a ring oscillator at the bus interface;
determining a clock ratio based on a comparison of a frequency of the third clock signal with a frequency of a fourth clock signal, wherein the first clock signal and second clock signal are based on the fourth clock signal; and
wherein the operational characteristic is based on the clock ratio.
3. The method of claim 1 , wherein adjusting the latency of the first clock signal comprises increasing the latency of the first clock signal and wherein adjusting the latency of the second clock signal comprises decreasing the latency of the second clock signal when the operational characteristic indicates that the operational speed is below an identified value.
4. The method of claim 3 , wherein adjusting the latency of the first clock signal comprises decreasing the latency of the first clock signal and wherein adjusting the latency of the second clock signal comprises increasing the latency of the second clock signal when the operational characteristic indicates that the operational speed is above an identified value.
5. The method of claim 4 , wherein the identified value is representative of a previously determined operational speed of the bus interface.
6. The method of claim 4 , wherein the identified value is representative of an operational speed of the bus interface under expected operating conditions.
7. The method of claim 1 , wherein the latency of the first clock signal is adjusted via a first programmable delay cell and the latency of the second clock signal is adjusted via a second programmable delay cell.
8. The method of claim 1 , wherein the latency of the first clock signal and the latency of the second clock signal are adjusted substantially simultaneously.
9. A method comprising:
determining a first operational characteristic representative of an operational speed of a circuit device at a first time;
receiving an input signal at an input of a first latch of the circuit device;
receiving an output signal at an input of a second latch of the circuit device, the output signal based on an output of the first latch;
delaying a clock signal by a first delay to provide a first adjusted clock signal, the first delay based on the first operational characteristic;
delaying the clock signal by a second delay to provide a second adjusted clock signal, the second delay based on the first operational characteristic;
latching the input signal at the first latch responsive to the first adjusted clock signal; and
latching the output signal at the second latch responsive to the second adjusted clock signal.
10. The method of claim 9 , further comprising:
determining a second operational characteristic representative of the operational speed of the circuit device at a second time subsequent to the first time;
delaying the clock signal by a third delay to provide a third adjusted clock signal, the third delay based on the second operational characteristic;
delaying the clock signal by a fourth delay to provide a fourth adjusted clock signal, the fourth delay based on the second operational characteristic;
latching the input signal at the first latch responsive to the third adjusted clock signal; and
latching the output signal at the second latch responsive to the fourth adjusted clock signal.
11. The method of claim 9 , wherein the operational characteristic is determined based on a change in a frequency of a clock signal generated at the circuit device.
12. The method of claim 9 , wherein:
the first delay is greater than the second delay when the first operational characteristic indicates that the operational speed is greater than an identified operational speed; and
the second delay is greater than the first delay when the first operational characteristic indicates that the operational speed is less than the identified operational speed.
13. The method of claim 12 , wherein the identified operational speed comprises a second operational speed of the circuit device at a second time prior to the first time.
14. The method of claim 12 , wherein the first delay is substantially equal to the second delay when the first operational characteristic indicates that the operational speed is substantially equal to the identified operational speed.
15. A system comprising:
first logic having an input to receive a first signal and an output;
second logic having an input to receive a second signal and an output;
a first latch having an input operably coupled to the output of the first logic, a clock input to receive a first clock signal, and an output to provide a first latched signal responsive to the first clock signal, wherein the second signal is based on the first latched signal;
a second latch having an input operably coupled to the output of the second logic, a clock input to receive a second clock signal, and an output to provide a second latched signal responsive to the second clock signal;
a first programmable delay cell having an input to receive a third clock signal, a plurality of delay paths having different delays, a select input to receive a signal indicating a selected delay path of the plurality of delay paths, and an output selectively coupled to the input via the selected delay path, wherein the output of the first programmable delay cell is to provide the first clock signal;
a second programmable delay cell having an input to receive the third clock signal, a plurality of delay paths having different delays, a select input to receive a signal indicating a selected delay path of the plurality of delay paths, and an output selectively coupled to the input via the selected delay path, wherein the output of the second programmable delay cell is to provide the second clock signal; and
an operational speed monitor having a first output coupled to the select input of the first programmable delay cell and a second output coupled to the select input of the programmable delay cell, wherein the operational speed monitor is to provide a first value via the first output and a second value via the second output based on an operational characteristic representation of an operational speed of the first logic and the second logic.
16. The system of claim 15 , wherein operational speed monitor comprises:
a ring oscillator having an output to provide a fourth clock signal; and
a counter having a first input coupled to the output of the ring oscillator, a second input to receive the third clock signal, and an output to provide a counter value representative of a ratio of a frequency of the fourth clock signal to a frequency of the third clock signal, wherein the operational characteristic comprises the counter value.
17. The system of claim 16 , further comprising:
a lookup table comprising a plurality of entries indexed by the counter value, each entry comprising a value for output via the first output of the operational speed monitor and a value for output via the second output of the operational speed monitor.
18. The system of claim 15 , wherein the input of the first logic comprises an input of the circuit device and the output of the second logic comprises an output of the circuit device.
19. The system of claim 15 , wherein the circuit device comprises a bus interface.
20. The system of claim 19 , wherein the first logic comprises input logic of the bus interface and the second logic comprises output logic of the bus interface.