Method and apparatus for determining actual write latency and accurately aligning the start of data capture with the arrival of data at a memory device

A memory device comprising:

• an input pad for receiving input data;
• a deserializer having a first input coupled to said input pad;
• and
• a delay circuit having an output coupled to a second input of said deserializer, said delay circuit providing an output signal to said deserializer, said deserializer in response to said output signal starting to capture said input data,
• wherein said delay circuit delays said start time of said capture of said input data to align said start time with arrival of said input data at said memory device.

A processor system comprising:

• a processing unit;
• and
• a memory device connected to said processing unit, said memory device comprising:
• a first circuit to determine a difference between an actual arrival time of test data and an expected arrival time of said test data at said memory device;
• and
• a delay circuit coupled to said first circuit, said delay circuit delaying a start time for capture of input data to said memory device based on said determined difference to align said start time for capture of said input data with an actual arrival time of said input data at said memory device.

A processor system comprising:

• a processing unit;
• and
• a memory device connected to said processing unit, said memory device comprising:
• an input pad for receiving input data;
• a deserializer having a first input coupled to said input pad;
• and
• a delay circuit having an output coupled to a second input of said deserializer, said delay circuit providing an output signal to said deserializer, said deserializer in response to said output signal starting to capture said input data,
• wherein said delay circuit delays said start time of said capture of said input data to align said start time with arrival of said input data at said memory device.

A method for writing input data to a memory device comprising the steps of:

• determining a difference between an actual receipt time of test data by said memory device and an expected receipt time of said test data by said memory device;
• receiving a write command to write said input data to said memory device;
• and
• delaying a start time of capture of said input data based on said determined difference to align said start time of capture with receipt of said input data.

A method for writing data to a memory device comprising the steps of:

• sending a write command to said memory device;
• sending said data to said memory device after waiting a specified amount of time, said specified amount of time based on a specified write latency of said memory device;
• and
• delaying a start of capture of said data a predetermined amount of time, said predetermined amount of time based on an actual write latency of said memory device, to align said start of capture of said data with receipt of said data by said memory device.