Abstract: Memory devices and methods for operating the same are provided. A memory device can include at least one command contact and at least one data contact. The memory device can be configured to detect a condition in which the at least one command contact is connected to a controller and the at least one data contact is disconnected from the controller, and to enter, based at least in part on detecting the condition, a first operating mode with a lower nominal power rating than a second operating mode. Memory modules including one or more such memory devices can be provided, and memory systems including controllers and such memory modules can also be provided.

Abstract: Methods, systems, and devices for self-refresh exit detection for memory devices are described. The described techniques provide for a memory system to indicate whether the memory system is in a self-refresh mode or not. The memory system may initiate a self-refresh operation for one or more memory cells of the memory system. The memory system may set a mode register to a first value based on initiating the self-refresh operation. The first value of the mode register may indicate that the self-refresh operation is being executed. The memory system may determine whether to reset the mode register to a second value based on a status of the self-refresh operation. The second value of the mode register may indicate that the self-refresh operation is complete. A host system may poll the mode register to determine the status of the self-refresh operation at the memory system.

Abstract: Methods, systems, and devices for memory operations are described. A command may be received by a memory device and from a device. Both the device and the memory device may maintain counters of valid operations. A request for a value associated with a counter at the memory device may be received from the device. Based on receiving the request, a value of the counter may be transmitted to the device. The values of the counters may be compared to determine whether invalid data has been obtained by the device. Also, a pin associated with communicating error correction information may be coupled with a voltage source based on receiving a signal. The pin may remain coupled with the voltage source until a command is processed or an end of the signal. Whether the pin is coupled with the voltage source may indicate a validity of associated data.

Abstract: Methods, systems, and devices are described herein for using codewords to detect or correct errors in data (e.g., data stored in a memory device). A host device may generate one or more codewords associated with data to be stored in the memory device. In some cases, the host device may generate one or more codewords for error detection and correction (e.g., corresponding to data transmitted by the host device to the memory device). In some cases, the host device may transmit the codewords and the associated data using an extended (e.g., adjustable) burst length such that the one or more codewords may be included in the burst along with the data. Additionally or alternatively, the host device may transmit one or more of the codewords over one or more channels different than the one or more channels used to transmit the data.

Abstract: Methods, systems, and devices for differential strobe fault indication are described. A memory device may be configured to indicate a fault using a read strobe signal. The read strobe signal may be a read data strobe (RDQS) signal, such as a true RDQS (RDQS_t) signal or a complement RDQS (RDQS_c) signal. In some examples, the memory device may indicate the fault based on a characteristic of the read strobe signal, such as a pattern of the read strobe signal, a voltage level of the read strobe signal, a difference between a first read strobe signal and a second read strobe signal, or any combination thereof. In some examples, a host device may indicate to the memory device which characteristic of the read strobe signal the memory device is to use to indicate the fault.

Abstract: Implementations described herein relate to command address fault detection using a parity bit. A memory device may receive, from a host device via a command address (CA) bus and during a unit interval, a set of CA bits associated with a CA word. The memory device may receive, from the host device via a parity bus and during the unit interval, a first parity bit that is based on the set of CA bits and a parity generation process. The memory device may generate a second parity bit based on the set of CA bits and the parity generation process. The memory device may compare the first parity bit and the second parity bit. The memory device may selectively transmit an alert signal to the host device based on a result of comparing the first parity bit and the second parity bit.

Abstract: Methods, systems, and devices for error detection and classification at a host device are described. A host device may communicate a read command for a codeword stored at a memory device. In response to communicating the read command, the host device may receive the codeword and an error indication bit that indicates whether the memory device detected an error in the codeword. The host device may use the codeword to generate a set of syndrome bits. The host device may determine an error status of the codeword based on the error indication bit for the codeword and the set of syndrome bits for the codeword.

Abstract: Methods, systems, and devices for a memory device with status feedback for error correction are described. For example, during a read operation, a memory device may perform an error correction operation on first data read from a memory array of the memory device. The error correction operation may generate second data and an indicator of a state of error corresponding to the second data. In one example, the indicator may indicate one of multiple possible states of error. In another example, the indicator may indicate a corrected error or no detectable error. The memory device may output the first or second data and the indicator of the state of error during a same burst interval. The memory device may output the data on a first channel and the indicator of the state of error on a second channel.

Abstract: Methods, systems, and devices for bit retiring to mitigate bit errors are described. A memory device may retrieve a set of bits from a first row of an address space and may determine that the set of bits includes one or more errors. The memory device may remap at least a portion of the first row from a first row index to a second row index, where the second row index, before the remapping, corresponds to a second row within the address space addressable by the host device. Additionally or alternatively, the memory device may receive a first command to access a first logical address of a memory array that is associated with a first row index. The memory device may determine that the first row includes one or more errors and may transmit a signal indicating that the first row includes the one or more errors.

Abstract: Methods, systems, and devices for targeted command/address parity low lift are described. A memory device may receive a command (e.g., a write command or a read command) from a host device over a first set of pins and may perform data transfer over a second set of pins with the host device during a set of time intervals according to the command. The memory device may exchange a parity bit associated with the command with the host device over a third set of pins during a first time intervals of the set of time intervals. In some cases, the third memory device may exchange at least one additional bit associated with the command with the host device during at least one time interval of the set of time intervals.

Abstract: Methods, systems, and devices for metadata storage at a memory device are described to support storage of metadata information and error control information at a memory device. The metadata information and error control information may be received at the memory device via a sideband channel and corresponding pin. For example, a set of bits received via the pin may include a subset of error control bits and a subset of metadata bits. Circuitry at the memory device may receive the set of bits via the pin and may identify metadata information and error control information within the set of bits. The circuitry may route the metadata information to a corresponding subset of memory cells and the error control information to an error control circuit, where the error control circuit may route the error control information to a corresponding subset of memory cells.

Abstract: Methods, systems, and devices for host error control matrix are described. A host device may implement a parity check matrix for generating error control information with a relatively low likelihood that a multi-bit error in a codeword associated with the error control information is mistaken for a single-bit error. The host device may implement a parity check matrix patterned such that when the error control information is generated, there is a relatively low likelihood that an error code resulting from a comparison of the error control information will yield an indication of a single-bit error when a multi-bit error occurs. For example, the host device may compare first error control information generated for a codeword and transmitted to a memory device with second error control information generated after receiving the codeword from the memory device, and generate an error code using the results of the comparison.

Abstract: Implementations described herein relate to performing a memory built-in self-test and indicating a status of the memory built-in self-test. A memory device may read one or more bits, associated with a memory built-in self-test, that are stored in a mode register of the memory device. The memory device may identify, based on the one or more bits, that the memory built-in self-test is enabled. The memory device may set a DMI bit of the memory device to a first value and perform the memory built-in self-test based on identifying that the memory built-in self-test is enabled. The memory device may set the DMI bit of the memory device to a second value based on a completion of the memory built-in self-test.

Abstract: Implementations described herein relate to command address fault detection using a parity bit. A memory device may receive, from a host device via a command address (CA) bus and during a unit interval, a set of CA bits associated with a CA word. The memory device may receive, from the host device via a parity bus and during the unit interval, a first parity bit that is based on the set of CA bits and a parity generation process. The memory device may generate a second parity bit based on the set of CA bits and the parity generation process. The memory device may compare the first parity bit and the second parity bit. The memory device may selectively transmit an alert signal to the host device based on a result of comparing the first parity bit and the second parity bit.

Abstract: Methods, systems, and devices for internal error correction for memory devices are described. A memory device may perform a read operation at a memory array having a data partition and an error check partition and may obtain a first set of bits from the data partition and a second set of bits from the error check partition. The memory device may determine a first error detection result based on a value of a determined syndrome. The memory device may obtain a parity bit from the first set of bits and determine a second error detection result based on a comparison of the parity bit with a second function of the subset of the first set of bits. The memory device may transmit the first set of bits to a host device based at least in part on the first and second error detection results.

Abstract: Implementations described herein relate to refresh rate selection for a memory built-in self-test. A memory device may read one or more bits, associated with the memory built-in self-test, that are stored in a mode register of the memory device. The memory device may identify, based on the one or more bits, a refresh rate to be used while performing the memory built-in self-test. The refresh rate may indicate a rate at which memory cells, to be tested by the memory built-in self-test, are to be refreshed while the memory built-in self-test is being performed. The memory device may perform the memory built-in self-test while refreshing the memory cells according to the refresh rate.

Abstract: Methods, systems, and devices for error detection and classification at a host device are described. A host device may communicate a read command for a codeword stored at a memory device. In response to communicating the read command, the host device may receive the codeword and an error indication bit that indicates whether the memory device detected an error in the codeword. The host device may use the codeword to generate a set of syndrome bits. The host device may determine an error status of the codeword based on the error indication bit for the codeword and the set of syndrome bits for the codeword.

Abstract: Methods, systems, and devices for memory operations are described. A read command may be received at a memory device from a host device. As part of an error control operation, a first set of error control bits may be generated for the set of data. Based on the first set of error control bits, a failure of a matching operation associated with the error control operation may be determined. Based on determining the failure of the matching operation, a second set of error control bits that is different than the first set of error control bits may be transmitted to the host device. The second set of error control bits may indicate that the matching operation failed at the memory device.

Abstract: Methods, systems, and devices for syndrome check functionality to differentiate between error types are described. A host system, a memory system, or some combination of both may include syndrome check circuitry to provide enhanced error diagnostic capabilities for data communicated between the host system and the memory system. The syndrome check circuitry may receive a first signal from the memory system indicating whether the memory system detected and attempted to correct an error in the data and may receive a second signal from the host system indicating whether the host system detected an error in the received data. The syndrome check circuitry may compare the first signal and the second signal using a set of logic gates to differentiate between different combinations of errors detected at one or both of the memory system or the host system.

Abstract: Methods, systems, and devices for metadata storage at a memory device are described to support storage of metadata information and error control information at a memory device. The metadata information and error control information may be received at the memory device via a sideband channel and corresponding pin. For example, a set of bits received via the pin may include a subset of error control bits and a subset of metadata bits. Circuitry at the memory device may receive the set of bits via the pin and may identify metadata information and error control information within the set of bits. The circuitry may route the metadata information to a corresponding subset of memory cells and the error control information to an error control circuit, where the error control circuit may route the error control information to a corresponding subset of memory cells.