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US 12,602,173 B2Granted
Serial presence detect logging
AssigneeRambus Inc.
InventorsAws Shallal, Chen Chen
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Abstract
A serial presence detect (SPD) device includes a region of nonvolatile memory for SPD data and an additional region for other (e.g., vendor) use. The additional region may be subdivided into write protect regions that can be individually and independently write protected. To configure the write protection, a password key scheme is used to enter a mode whereby the write protection attributes may be configured. Another password key scheme is used to exit the write protection configuration mode.
Claims20
A controller, comprising:
- a serial presence detect device interface to communicate commands and data to a serial presence detect device;
- the controller to access, via the serial presence detect device interface, a first plurality of nonvolatile memory locations storing serial presence detect information according to a serial presence detect standard;
- the controller to access, via the serial presence detect device interface, a second plurality of nonvolatile memory locations subject to configurable write access protection enforced by the serial presence detect device;
- and
- the controller to configure the serial presence detect device to change the write access protection to be not configurable by transmitting, to the serial presence detect device and via the serial presence detect device interface, a first write command to write a first value stored in a password register of the serial presence detect device and by transmitting, in succession to the first write command, a second write command to write a second value that is not stored in the password register.
2 more elements
A controller, comprising:
- a first interface to communicate commands and addresses with a plurality of volatile memory devices disposed on a module;
- a second interface to communicate data with the plurality of volatile memory devices disposed on the module;
- a serial presence detect device interface to communicate with a serial presence detect device, the serial presence detect device comprising:
- a password register;
- a first plurality of nonvolatile memory locations to store serial presence detect information about the plurality of volatile memory devices disposed on the module;
- and
- a second plurality of nonvolatile memory locations to store first data, the second plurality of nonvolatile memory locations subject to write access protection;
- and
- the controller to configure the write access protection to be not configurable by transmitting, to the serial presence detect device via the serial presence detect device interface, a first write command to write a first value stored in the password register and by transmitting, in succession to the first write command, to the serial presence detect device, and via the serial presence detect device interface, a second write command to write a second value that is not stored in the password register.
6 more elements
A method, comprising:
- accessing, by a controller, serial presence detect information stored in a first plurality of nonvolatile memory locations of a serial presence detect device;
- accessing, by the controller and subject to write access protection enforced by the serial presence detect device, a second plurality of nonvolatile memory locations that store first data;
- and
- writing, by the controller and to the serial presence detect device, a first value stored in a password register of the serial presence detect device and in succession to writing the first value, writing, by the controller and to the serial presence detect device, a second value that is not stored in the password register of the serial presence detect device to cause the serial presence detect device to change the write access protection of the second plurality of nonvolatile memory locations to become not configurable.
1 more element
Dependencies are inferred from the claim text.