Abstract: Methods, systems, and devices for strategic power mode transition in a multi-memory device are described. A controller may receive, from a host device, a command indicating that the controller is to transition a volatile memory and a non-volatile memory from respective deep sleep modes. In a first example, the controller may respond to the command by transitioning the volatile memory to a standby power mode for the volatile memory and transitioning the non-volatile memory to an intermediate power mode for the non-volatile memory that consumes less power than a standby mode for the non-volatile memory. In a second example, the controller may respond to the command by transitioning the volatile memory to the standby power mode for the volatile memory and maintain the non-volatile memory in the deep sleep mode until a condition, such as a miss, occurs.

Abstract: Methods, systems, and devices for power mode control in a multi-memory device are described. An apparatus may include a non-volatile memory and a volatile memory. The apparatus may operate the volatile memory in a first power mode and the non-volatile memory in a second power mode. The apparatus may transition the volatile memory from the first power mode to a third power mode based on a power mode command from a host device. The apparatus may transition the non-volatile memory from the second power mode to a fourth power mode that consumes less power than the second power mode irrespective of the command from the host device and based on a quantity of queued commands for the non-volatile memory being less than a threshold quantity.

Abstract: Methods, systems, and devices for scratchpad memory in a cache are described. A device may operate a portion of a volatile memory in a cache mode having non-deterministic latency for satisfying requests from a host device. The device may monitor a register with an output pin that is associated with the portion and indicative of an operating mode of the portion. Based on or in response to monitoring the output pin, the device may determine whether to change the operating mode of the portion from the cache mode to a scratchpad mode having deterministic latency for satisfying requests from the host device.

Abstract: Methods, systems, and devices for hazard detection in a multi-memory device are described. A device may receive a first command that indicates a first bank address, a first row address, and a first column address. Based on the first bank address, the device may select a buffer for a hazard detection procedure that detects hazardous commands. The device may compare, as part of the hazard detection procedure, the first row address and the first column address from the first command with a second row address and a second column address from a second command in the buffer. The device may determine whether the first command and the second command are hazardous commands based on comparing the first row address and the first column address from the first command with the second row address and the second column address from the second command.

Abstract: Methods, systems, and devices for post error correction code (ECC) registers for cache metadata are described. A device may read metadata from a memory array included in the device. The metadata may include information for operating a volatile memory as a cache for a non-volatile memory. The device may perform an ECC operation on the metadata based on reading the metadata from the memory array. After performing the ECC operation on the metadata, the device may write the metadata to a register that is coupled with the memory array. The device may then write the metadata from the register to the memory array.

Abstract: Methods, systems, and devices for memory wear management are described. A device may include an interface controller and a non-volatile memory. The interface controller may manage wear-leveling procedures for memory banks in the non-volatile memory. For example, the interface controller may select a row in a memory bank for the wear-leveling procedure. The interface controller may store data from the row in a buffer in the interface controller. The interface controller may then transfer the data to the non-volatile memory so that the non-volatile memory can write the data to a second row of the memory bank.

Abstract: Methods, systems, and devices for transaction management using metadata are described. In some examples, a memory device may include a volatile memory, and a non-volatile memory, which may have different access latencies. The memory device may receive from a host device a read command for data located at an address of the non-volatile memory. In response to the read command, the memory device and may determine whether the data is stored in the volatile memory. The memory device may then transmit, to the host device data and according to an expected latency, a set of data and an indication of whether the set of data was previously requested by the host device or unrequested by the host device. In some examples, the memory device may also transmit an identifier associated with the read command and a hash of the address.

Abstract: Methods, systems, and devices for transaction management based on metadata are described. A host device may transmit a read command to a memory device. Based on the read command, the host device may receive a set of data from the memory device. The host device may also receive metadata associated with the set of data. Based on the metadata, the host device may determine whether the set of data is the data requested by the read command, data requested by a previous read command, or data unrequested by the host device, or some combination. If the set of data is the data requested by the read command or a previous read command, the host device may process the set of data accordingly. If the set of data is data unrequested by the host device, the host device may discard the set of data and retransmit the read command.

Abstract: Methods, systems, and devices for post error correction code (ECC) registers for cache metadata are described. A device may read metadata from a memory array included in the device. The metadata may include information for operating a volatile memory as a cache for a non-volatile memory. The device may perform an ECC operation on the metadata based on reading the metadata from the memory array. After performing the ECC operation on the metadata, the device may write the metadata to a register that is coupled with the memory array. The device may then write the metadata from the register to the memory array.

Abstract: Methods, systems, and devices for hazard detection in a multi-memory device are described. A device may receive a first command that indicates a first bank address, a first row address, and a first column address. Based on the first bank address, the device may select a buffer for a hazard detection procedure that detects hazardous commands. The device may compare, as part of the hazard detection procedure, the first row address and the first column address from the first command with a second row address and a second column address from a second command in the buffer. The device may determine whether the first command and the second command are hazardous commands based on comparing the first row address and the first column address from the first command with the second row address and the second column address from the second command.

Abstract: Methods, systems, and devices for cache management in a memory subsystem are described. A device may determine to perform an eviction procedure for a bank of a volatile memory that operates as a cache for a non-volatile memory. The eviction procedure may save data from the bank of the volatile memory to the non-volatile memory. The device may determine an activity status for at least one buffer in a pool of buffers that are coupled with the volatile memory and the non-volatile memory. The device may select the at least one buffer in the pool of buffers for the eviction procedure for the bank of the volatile memory based at least in part on the activity status for that buffer.

Abstract: Methods, systems, and devices for direct testing of in-package memory are described. A memory subsystem package may include non-volatile memory, volatile memory that may be configured as a cache, and a controller. The memory subsystem may support direct access to the non-volatile memory for testing the non-volatile memory in the package using a host interface of the memory subsystem rather than using dedicated contacts on the package. To ensure deterministic behavior during testing operations, the memory subsystem may, when operating with a test mode enabled, forward commands received from a host device (such as automated test equipment) to a memory interface of the non-volatile memory and bypass the cache-related circuitry. The memory subsystem may include a separate conductive path that bypasses the cache for forwarding commands and addresses to the memory interface during testing.

Abstract: Methods, systems, and devices for metadata management for a cache are described. An interface controller may include a first array and a second array that store metadata for a cache memory. The interface controller may receive an activate command associated with a row of the cache memory. In response to the activate command, the interface controller may communicate storage information for the row of the volatile memory from a first array to a first register. The interface controller may receive an access command associated with the row of the cache memory. In response to the access command and based on the storage information in the first register, the interface controller may communicate validity information for the row from a second array to the first register or dirty information for the row from the second array to a second register.

Abstract: Methods, systems, and devices for quality-of-service information for a multi-memory system are described. An interface controller may receive a first command from a host device during a set of clock cycles. The first command may be received over a command bus that includes a pin, such as a command select pin configured for double data rate signaling. The interface controller may decode the first command based on a state of the command select pin during at least one clock cycle of the set of clock cycles. And the interface controller may determine quality-of-service information for a second command based on decoding the first command and on information, such as a plurality of bits, included in the first command.

Abstract: Methods, systems, and devices for power mode control in a multi-memory device are described. An apparatus may include a non-volatile memory and a volatile memory. The apparatus may operate the volatile memory in a first power mode and the non-volatile memory in a second power mode. The apparatus may transition the volatile memory from the first power mode to a third power mode based on a power mode command from a host device. The apparatus may transition the non-volatile memory from the second power mode to a fourth power mode that consumes less power than the second power mode irrespective of the command from the host device and based on a quantity of queued commands for the non-volatile memory being less than a threshold quantity.

Abstract: Methods, systems, and devices for strategic power mode transition in a multi-memory device are described. A controller may receive, from a host device, a command indicating that the controller is to transition a volatile memory and a non-volatile memory from respective deep sleep modes. In a first example, the controller may respond to the command by transitioning the volatile memory to a standby power mode for the volatile memory and transitioning the non-volatile memory to an intermediate power mode for the non-volatile memory that consumes less power than a standby mode for the non-volatile memory. In a second example, the controller may respond to the command by transitioning the volatile memory to the standby power mode for the volatile memory and maintain the non-volatile memory in the deep sleep mode until a condition, such as a miss, occurs.

Abstract: Methods, systems, and devices for scratchpad memory in a cache are described. A device may operate a portion of a volatile memory in a cache mode having non-deterministic latency for satisfying requests from a host device. The device may monitor a register with an output pin that is associated with the portion and indicative of an operating mode of the portion. Based on or in response to monitoring the output pin, the device may determine whether to change the operating mode of the portion from the cache mode to a scratchpad mode having deterministic latency for satisfying requests from the host device.

Abstract: Methods, systems, and devices for centralized error correction circuit are described. An apparatus may include a non-volatile memory disposed on a first die and a volatile memory disposed on a second die (different than the first die). The apparatus may also include an interface controller disposed on a third die (different than the first die and the second die). The interface controller may be coupled with the non-volatile memory and the volatile memory and may include an error correction circuit that is configured to operate on one or more codewords received from the volatile memory.

Abstract: Methods, systems, and devices for opportunistic data movement are described. A memory device may include a non-volatile memory and a volatile memory that operates as a cache for the non-volatile memory. The memory device may receive a write command from a host device. The write command may be associated with a row of a bank in a volatile memory. The memory device may write data associated with the write command to a buffer that is associated with the bank and that is coupled with the volatile memory. And the memory device may communicate the data from the buffer to the volatile memory based on the write command and before a pre-charge command for the row of the bank is received from the host device.

Abstract: Methods, systems, and devices for improved techniques for partial writes are described. A memory device may include a non-volatile memory and a volatile memory configured to operate as a cache for the non-volatile memory. The memory device may receive, from a host device, a write command for a first data set provided by the host device. Based on the write command, the memory device may store the first data set in a buffer coupled with a volatile memory. After storing the first data set in the buffer, the memory device may communicate to the volatile memory a set of data that includes the first data set and a second data set. The first data set and the second data may be associated with adjacent addresses for the volatile memory and may each have sizes smaller than a threshold size associated with the volatile memory.