Abstract:
A memory subsystem enables per device addressability (PDA) to target configuration commands to one of multiple memory devices that share a select line or buffer devices that share an enable line. The system includes a host and multiple memory devices that can be coupled over a command bus and a data bus. The devices include a configuration or mode register to store a value to indicate whether PDA enumeration is enabled. When enabled, the host can provide an enumeration identifier (ID) command via the command bus with a signal via the data bus to assign an enumeration ID. After assignment of the enumeration ID, the host can send PDA commands via the command bus with the enumeration ID, without a signal on the data bus. Devices only process PDA commands that match their assigned enumeration ID, enabling the setting of device-specific configuration settings without needing to use the data bus on every PDA command.
Abstract:
Error correction in a memory subsystem includes a memory device generating internal check bits after performing internal error detection and correction, and providing the internal check bits to the memory controller. The memory device performs internal error detection to detect errors in read data in response to a read request from the memory controller. The memory device selectively performs internal error correction if an error is detected in the read data. The memory device generates check bits indicating an error vector for the read data after performing internal error detection and correction, and provides the check bits with the read data to the memory controller in response to the read request. The memory controller can apply the check bits for error correction external to the memory device.
Abstract:
Provided are a method and apparatus for performing error handling operations using error signals A first error signal is asserted on an error pin on a bus to signal to a host memory controller that error handling operations are being performed by a memory module controller in response to detecting an error. Error handling operations are performed to return the bus to an initial state in response to detecting the error. A second error signal is asserted on the error pin on the bus to signal that error handling operations have completed and the bus is returned to the initial state.
Abstract:
Provided are a method and apparatus for providing a host memory controller write credits for write commands. A host memory controller coupled to a memory module over a bus determines whether a read data packet returned from the memory module indicates at least one write credit and increments a write credit counter in response to determining that the read data packet indicates at least one write credit.
Abstract:
Provided are a method and apparatus for a memory module to accept a command in multiple parts. A first half of a command is placed on a bus for a memory module in a first clock cycle. A chip select signal is placed on the bus for the memory module for the first half of the command. A second half of the command is placed on the bus in a second clock cycle following the first clock cycle, wherein the memory module accepts the second half of the command a delay interval from accepting the first half of the command.
Abstract:
Provided are a method and apparatus for determining a timing adjustment of output to a host memory controller in a first memory module coupled to a host memory controller and a second memory module over a bus. A determination is made of a timing adjustment based on at least one component in at least one of the first memory module and the second memory module. A timing of output to the host memory controller is adjusted based on the determined timing adjustment to match a timing of output at the second memory module.
Abstract:
Self-test and repair of memory cells is performed in a memory integrated circuit by two separate processes initiated by a memory controller communicatively coupled to the memory integrated circuit. To ensure that the repair process is completed in the event of an unexpected power failure, a first process is initiated by the memory controller to perform a memory Built-in Self Test (mBIST) in the memory integrated circuit and a second process is initiated by the memory controller after the mBIST has completed to perform repair of faulty memory cells detected during the MBIST process. The memory controller does not initiate the repair process if a power failure has been detected. In addition, a repair time associated with the repair process is selected such that the repair time is sufficient to complete the repair process while power is stable, if a power failure occurs after the repair process has been started.
Abstract:
A memory device with internal row hammer mitigation couples to a memory controller. The memory controller or host can assist with row hammer mitigation by sending additional refresh cycles or refresh commands. In response to an extra refresh command the memory device can perform refresh for row hammer mitigation instead of refresh for standard data integrity. The memory controller can keep track of the number of activate commands sent to the memory device, and in response to a threshold number of activate commands, the memory controller sends the additional refresh command. With the extra refresh command the memory device can refresh the potential victim rows of a potential aggressor row, instead of simply refreshing a row that has not been accessed for a period of time.
Abstract:
A memory device can internally track row address activates for perfect row hammer tracking, incrementing an activate count for each row when an access command is received for a row. Instead of incrementing the count for each activate, the memory controller can indicate a number greater than one for the memory device to increment the count, and then indicate not to increment the count for subsequent accesses up to the number indicated. The memory controller can determine whether the row address of an activate command is one of N recent row addresses that received the access command. The memory controller can indicate an increment of zero if the row address is one of the N recent addresses, and indicate an increment of a number higher than one if the row address is not one of the N recent addresses.
Abstract:
A memory chip is described. The memory chip includes storage cells along a row of the memory chip's storage cell array to store a count value of the row's activations and error correction code (ECC) information to protect the count value. The memory chip includes ECC read logic circuitry to correct an error in the count value. The memory chip includes a comparator to compare the count value against a threshold. The memory chip includes circuitry to increment the count value if the count value is deemed not to have reached the threshold and ECC write logic circuitry to determine new ECC information for the incremented count value, and write driver circuitry to write the incremented count value and the new ECC information into the storage cells. The memory chip includes circuitry to cause the row to be refreshed if the count value is deemed to have reached the threshold.