Mechanism for data generation in data processing systems
View Patent ↗An integrated circuit includes enable circuitry coupled to receive transmit data and configured to set a clock enable to a first logic state when a data value of the transmit data changes to a different logic state. The circuit also includes clock control circuitry coupled to receive the clock enable and a data rate clock and configured to provide a filtered data rate clock, wherein the data rate clock is provided as the filtered data rate clock while the clock enable is the first logic state. The circuit also includes a flip flop having a clock input coupled to receive the filtered data rate clock, a data output coupled to provide final transmit data in response to the filtered data rate clock, and an inverting data input coupled to the data output, wherein the final transmit data corresponds to a first delayed version of the transmit data.
1. An integrated circuit, comprising:
enable circuitry coupled to receive transmit data and configured to set a clock enable to a first logic state when a data value of the transmit data changes to a different logic state;
clock control circuitry coupled to receive the clock enable and a data rate clock and configured to provide a filtered data rate clock, wherein the clock control circuitry is configured to provide the data rate clock as the filtered data rate clock while the clock enable is the first logic state; and
a flip flop having a clock input coupled to receive the filtered data rate clock, a data output coupled to provide final transmit data in response to the filtered data rate clock, and an inverting data input coupled to the data output, wherein the final transmit data corresponds to a first delayed version of the transmit data received by the enable circuitry.
2. The integrated circuit of claim 1 , wherein the enable circuitry comprises:
a delay unit coupled to receive the transmit data and configured to provide a second delayed version of the transmit data received by the enable circuitry; and
a comparator having a first input coupled to the transmit data and a second input coupled to receive the second delayed version of the transmit data, and an output to provide the clock enable based on comparisons between data values of the transmit data and the second delayed version of the transmit data.
3. The integrated circuit of claim 2 , wherein the transmit data and the second delayed version of the transmit data are delayed with respect to each other by a predetermined number of clock cycles of the data rate clock.
4. The integrated circuit of claim 1 , wherein the clock control circuitry is configured to delay the clock enable prior to using the clock enable to provide the filtered data rate clock.
5. The integrated circuit of claim 1 , wherein the enable circuitry is configured to set the clock enable to a second logic state, different from the first logic state, when the data value of the transmit data does not change.
6. The integrated circuit of claim 1 , wherein the clock control circuitry is configured to provide a predetermined logic state as the filtered data rate clock while the clock enable is negated.
7. The integrated circuit of claim 1 , further comprising:
a delay chain coupled between the clock control circuitry and the flip flop, wherein the delay chain is configured to delay the filtered data rate clock prior to providing the filtered data rate clock to the clock input of the flip flop.
8. The integrated circuit of claim 7 , wherein the delay chain affects a duty cycle of the filtered data rate clock provided to the clock input of the flip flop.
9. The integrated circuit of claim 7 , wherein the flip flop is configured to provide values of the final transmit data in response to one of rising or falling edges of the filtered data rate clock provided to the clock input of the flip flop.
10. A method, comprising:
comparing transmit data to a first delayed version of the transmit data to generate a clock enable signal;
generating a filtered data rate clock signal based on a data rate clock signal and the clock enable signal, wherein the data rate clock signal is provided as the filtered data rate clock signal when the clock enable signal has a first logic state and a predetermined logic state is provided as the filtered data rate clock signal when the clock enable signal has a second logic state; and
generating final transmit data in response to one of rising or falling edges of the filtered data rate clock signal, wherein the final transmit data corresponds to a second delayed version of the transmit data.
11. The method of claim 10 , wherein the comparing the transmit data to the first delayed version of the transmit data to generate the clock enable signal comprises:
setting the clock enable signal to the first logic state when compared values are different logic states; and
setting the clock enable signal to the second logic state when compared values are a same logic state.
12. The method of claim 11 , wherein the transmit data and the first delayed version of the transmit data are delayed with respect to each other by a predetermined number of clock cycles of the data rate clock signal.
13. The method of claim 10 , further comprising:
delaying the filtered data rate clock signal through a delay chain prior to generating the final transmit data.
14. The method of claim 10 , further comprising:
delaying the clock enable signal prior to generating the filtered data rate clock signal based on the data rate clock signal and the clock enable signal.
15. The method of claim 10 , wherein the generating the final transmit data in response to the one of the rising or falling edges of the filtered data rate clock signal comprises:
providing the filtered data rate clock signal to a clock input of a flip flop; and
providing a data output of the flip flop to an inverting data input of the flip flop, wherein the data output of the flip flop provides the final transmit data.
16. An integrated circuit, comprising:
a first delay unit having an input to receive transmit data and an output to provide a first delayed version of the transmit data;
a comparator having a first input coupled to receive the transmit data, a second input coupled to receive the first delayed version of the transmit data, and an output coupled to provide a clock enable signal;
clock control circuitry coupled to receive the clock enable and a data rate clock and coupled to provide a filtered data rate clock, wherein the clock control circuitry is configured to provide the data rate clock as the filtered data rate clock while the clock enable has a first logic state;
a delay chain having an input to receive the filtered data rate clock and an output coupled to provide a delayed filtered data rate clock; and
a flip flop having a clock input coupled to receive the delayed filtered data rate clock, a data output coupled to provide final transmit data in response to the filtered data rate clock, and an inverting data input coupled to the data output, wherein the final transmit data corresponds to a second delayed version of the transmit data received by the first delay unit.
17. The integrated circuit of claim 16 , wherein the comparator is configured to set the clock enable signal to the first logic state when values at the first and second inputs are different logic states and set the clock enable signal to a second logic state, different from the first logic state, when values at the first and second inputs are a same logic state.
18. The integrated circuit of claim 16 , wherein the transmit data and the first delayed version of the transmit data are delayed with respect to each other by a predetermined number of clock cycles of the data rate clock.
19. The integrated circuit of claim 16 , wherein the delay chain affects a duty cycle of the delayed filtered data rate clock provided to the clock input of the flip flop.
20. The integrated circuit of claim 16 , wherein the flip flop is configured to provide values of the final transmit data in response to one of rising or falling edges of the delayed filtered data rate clock.