Memory controller for strobe-based memory systems
An integrated circuit (IC) memory controller is disclosed. The memory controller includes a receiver to receive a strobe signal and provide an internal strobe signal. An adjustable delay circuit delays an enable signal to generate a delayed enable signal. A gate circuit generates a gated strobe signal using the delayed enable signal that masks transitions of the internal strobe signal that occur prior to a valid region of the internal strobe signal. A sample circuit samples data using the gated strobe signal.
1. An integrated circuit (IC) memory controller comprising:
a timing signal pin to receive a timing signal having first timing information;
a delay circuit to delay an enable signal by a selectable delay to generate a delayed enable signal having second timing information, the enable signal corresponding to transitions of the timing signal that indicate the presence of valid data;
a mask circuit to generate a masked timing signal using the first timing information and the second timing information; and
a sampler to sample data using the masked timing signal.
2. The IC memory controller according to claim 1 , wherein the mask circuit masks at least a portion of the timing signal in generating the masked timing signal.
3. The IC memory controller according to claim 2 , wherein the timing signal is a strobe signal having preamble transitions and postamble transitions, and wherein the mask circuit masks at least one of the preamble transitions or the postamble transitions in generating the masked timing signal.
4. The IC memory controller according to claim 1 , embodied as a dynamic random access memory (DRAM) memory controller.
5. The IC memory controller according to claim 1 , wherein the delay circuit is responsive, during an initialization mode, to programming of a value representing the selectable delay.
6. The IC memory controller according to claim 5 , further comprising storage to store the value corresponding to the selectable delay determined during the initialization mode, the storage accessible by the delay circuit during an operation mode.
7. The IC memory controller according to claim 6 , wherein the storage comprises a programmable register.
8. A method of operation in a memory controller, the method comprising:
receiving a timing signal having first timing information;
delaying an enable signal by a selectable delay to generate a delayed enable signal having second timing information, the enable signal corresponding to transitions of the timing signal that indicate the presence of valid data;
generating a masked timing signal using the first timing information and the second timing information; and
sampling data using the masked timing signal.
9. The method according to claim 8 , wherein generating a masked timing signal comprises:
masking at least a portion of the timing signal.
10. The method according to claim 9 , wherein the timing signal is a strobe signal having preamble transitions and postamble transitions, and wherein the masking comprises:
masking at least one of the preamble transitions or the postamble transitions in generating the masked timing signal.
11. The method according to claim 8 , further comprising receiving the enable signal from a memory device.
12. The method according to claim 8 , further comprising:
during an initialization mode, programming of a value representing the selectable delay.
13. The method according to claim 12 , further comprising:
storing the value; and
during an operation mode, retrieving the value for use as the selectable delay.
14. An integrated circuit (IC) chip comprising:
memory control circuitry including
means for receiving a timing signal having first timing information;
means for delaying an enable signal by a selectable delay to generate a delayed enable signal having second timing information, the enable signal corresponding to transitions of the timing signal that indicate the presence of valid data;
means for generating a masked timing signal using the first timing information and the second timing information; and
means for sampling data using the masked timing signal.
15. The IC chip according to claim 14 , embodied as a dynamic random access memory (DRAM) memory controller.
16. The IC chip according to claim 14 , wherein the means for generating a masked timing signal comprises:
a mask circuit to mask at least a portion of the timing signal in generating the masked timing signal.
17. The IC chip according to claim 16 , wherein the timing signal is a strobe signal having preamble transitions and postamble transitions, and wherein the mask circuit masks at least one of the preamble transitions or the postamble transitions in generating the masked timing signal.
18. The IC chip according to claim 14 , wherein the means for delaying comprises a delay circuit, and wherein the delay circuit is responsive, during an initialization mode, to programming of a value representing the selectable delay.
19. The IC chip according to claim 18 , further comprising:
storage to store the value corresponding to the selectable delay determined during the initialization mode, the storage accessible by the delay circuit during an operation mode.
20. The IC chip according to claim 19 , wherein the storage comprises a programmable register.