Method and apparatus for a self-timed and self-enabled distributed clock

A distributed clock system for a digital circuit, comprising:

• a first self clock that provides first output clock pulses when enabled, the first self clock comprising:
• an output, a first input coupled to the output and a second input;
• wherein the first self clock is enabled by each clock pulse received at the second input and synchronizes the first output clock pulses with respective clock signals received at the second input;
• and
• a second self clock that provides second output clock pulses when enabled, the second self clock comprising:
• an output, a first input coupled to the output of the second self clock, and a second input coupled to the output of the first self clock;
• wherein the second self clock is enabled by each clock pulse received at the second input and synchronizes the second output clock pulse with respective clock signals received at the second input of the second self clock.

A processor, comprising:

• a plurality of functional blocks, each comprising:
• a queue buffer having a data input and a data output, the data input being the data input of the respective functional block;
• an execution unit that has an input coupled to the data output of the queue buffer and an execution data output, the execution output being the data output of the respective functional block;
• a self clock that has an output, a first clock input, a feedback input coupled to the output of the self clock, and an enable input;
• the self clock, when enabled, providing output clock pulses that are synchronized with clock pulses received at the first clock input;
• and
• a control block, coupled to the queue buffer, the execution unit and self clock, that has an enable output coupled to the enable input of the self clock;
• the control block enabling the self clock while the execution unit is processing data and while clock pulses are received at the first clock input of the self clock;
• and
• the plurality of functional blocks including a first and second functional blocks coupled together;
• wherein a first clock input of the second functional block is coupled to a clock output of the first functional block, and wherein the data output of the first functional block is coupled to the data input of the second functional block.

A method of operating each of a plurality of coupled functional blocks of a digital system, comprising:

• receiving input data and corresponding first input clock pulses;
• activating a self clock to provide an output clock pulse for each first input clock pulse;
• processing the input data and generating output data;
• generating, by the self clock, an output clock pulse to correspond with each output data;
• and
• deactivating the self clock while first input clock pulses are not received or during a stall condition.