SDRAM DIMM presence detect interface
AssigneeCirrus Logic, Inc.
InventorsPete Edward Nelsen, Douglas Michael Berk, Kenneth Ma
Life of this patent
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Abstract
A keyboard controller is used to drive the PDEN pins on DIMMs. A PC has a keyboard controller with a plurality of programmable input/output (I/O) pins. The state of the programmable I/O pins can be set by software. The pins are coupled to individual PDEN pins on the DIMMs. When the programmable I/O pins are activated, the PDEN pins are driven active and each DIMM outputs a signal indicating its characteristics. The signals are latched and stored for use by a memory controller.
Claims24
A method of determining characteristics of a memory module in a computer system, comprising the steps of:
- sending a first signal directly from a programmable input/output pin to a presence detect enable input on a DIMM, wherein the first signal is sent by a keyboard controller;
- and
- receiving a second signal from the DIMM, wherein the second signal is generated by the DIMM in response to the first signal, and wherein the second signal is utilized in determining the characteristics of the DIMM.
A system for detecting the presence of a memory module in a computer system, comprising:
- first means for sending a first signal directly from a programmable input/output pin on a keyboard controller to a presence detect enable input on a DIMM, wherein means within the DIMM generates a second signal in response to the first signal;
- second means independent from the first means for receiving the second signal, wherein the detecting the presence of the DIMM is a function of said second signal.
A system for detecting characteristics of a memory in a computer system, wherein the memory comprises at least one DIMM having a first input and a plurality of outputs and wherein the at least one DIMM generates an output signal on the plurality of outputs in response to an input signal on the first input, comprising:
- a keyboard controller having at least one programmable I/O pin, the at least one programmable I/O pin coupled directly to the first input, wherein said first input is a presence detect enable pin on a DIMM;
- and
- a memory controller having a plurality of second inputs coupled to the plurality of outputs.
Dependencies are inferred from the claim text.