Flash with consistent latency for read operations

1. A synchronous memory device comprising:

a pipeline data buffer having an input connection and an output connection, the pipeline data buffer has a plurality of selectable propagation paths to route data from the input connection to the output connection wherein each propagation path requires a predetermined number of clock cycles;

a multiplex circuit coupled to the input of the pipeline data buffer, the multiplex circuit having a first and second input;

a data register circuit coupled to the first input of the multiplex circuit; and

a data read circuit coupled to the second input of the multiplex circuit, the data read circuit provides output data read from a memory array of the synchronous memory device.

2. The synchronous memory device of claim 1 wherein the pipeline data buffer has three propagation paths that can be selected to provide one, two or three clock latency during read operations.

3. The synchronous memory device of claim 1 wherein the data register circuit comprises a status register to provide status data.

4. The synchronous memory device of claim 3 wherein the status data comprises

one of an active status of a state machine of the synchronous memory device, a memory array bank status, or an operation error data.

5. The synchronous memory device of claim 1 wherein the array of memory cells comprises an array of non-volatile memory cells.

6. A synchronous flash memory device comprising:

an array of non-volatile memory cells;

a pipeline data buffer having an input connection and an output connection, the pipeline data buffer has a plurality of selectable propagation paths to route data from the input connection to the output connection wherein each propagation path requires a predetermined number of clock cycles;

a multiplex circuit coupled to the input of the pipeline data buffer, the multiplex circuit having a first and second input;

a data register circuit coupled to the first input of the multiplex circuit; and

a data read circuit coupled to the second input of the multiplex circuit, the data read circuit provides output data read from the array of non-volatile memory cells, such that data from the data register circuit and the data read circuit propagate through the pipeline data buffer circuit using one of the plurality of selectable propagation paths.

7. The synchronous memory device of claim 6 wherein the pipeline data buffer has three propagation paths that can be selected to provide one, two or three clock latency during read operations.

8. A processing system comprising:

a memory controller; and

a synchronous flash memory device coupled to the memory controller and comprising:

an array of non-volatile memory cells,

a pipeline data buffer having an input connection and a data output connection, the pipeline data buffer has a plurality of selectable propagation paths to route data from the input connection to the data output connection wherein each propagation path requires a predetermined number of clock cycles, the data output connection is coupled to the memory controller via a data bus,

a multiplex circuit coupled to the input of the pipeline data buffer, the multiplex circuit having a first and second input,

a status register circuit coupled to the first input of the multiplex circuit, and

a memory read circuit coupled to the second input of the multiplex circuit, the data read circuit provides data read from the array of non-volatile memory cells, such that data from the status register circuit and the memory read circuit propagate through the pipeline data buffer circuit using one of the plurality of selectable propagation paths.

9. The processing system of claim 8 wherein the plurality of selectable propagation paths comprise one, two and three clock cycle propagation delays.

10. A method of reading data from a synchronous memory device, the method comprising:

coupling either memory cell data or status data to an input connection of a pipeline data buffer;

propagating the memory cell data or the status data through the pipeline data buffer; and

outputting either the memory cell data or the status data on external data connections.

11. The method of claim 10 wherein coupling either the memory cell data or the status data comprises:

reading the memory cell data and coupling the memory cell data to a first input of a multiplex circuit;

reading the status data and coupling the status data to a second input of the multiplex circuit; and

selectively coupling either the first or second input to the pipeline data buffer through the multiplex circuit.

12. The method of claim 10 wherein the pipeline data buffer has a plurality of selectable propagation paths.

13. The method of claim 12 wherein the plurality of selectable propagation paths have a time delay of one, two or three clock cycles.

14. A method of reading data from a synchronous memory device, the method comprising:

reading memory cell data and coupling the memory cell data to a first input of a multiplex circuit;

reading status data from a status register and coupling the status data to a second input of the multiplex circuit;

selectively coupling either the first or second input to an input of a pipeline data buffer through the multiplex circuit, wherein the pipeline data buffer has a plurality of selectable propagation paths;

propagating the memory cell data or the status data through the pipeline data buffer; and

outputting either the memory cell data or the status data on external data connections.

15. The method of claim 14 wherein the plurality of selectable propagation paths have a time delay of either one, two or three clock cycles.