摘要:
Phase-change memory (PCM) cells store data using alloy resistors in high-resistance amorphous and low-resistance crystalline states. The memory cell's reset current can be double a set current, causing peak currents to depend on write data. When all data bits are reset to the amorphous state, a very high peak current is required. To reduce this worst-case peak current, the data is encoded before storage in the PCM cells. An 8/10 encoder adds 2 bits but ensures that no more than half of the data bits are reset. An 8/9 encoder adds an indicator bit, and inverts the 8 bits to ensure that no more than half of the bits are reset. The indicator bit indicates when the 8 bit are inverted, and when the 8 bits are uninverted. Peak currents are thus reduced by encoding to reduce reset data bits.
摘要:
Phase-change memory (PCM) cells store data using alloy resistors in high-resistance amorphous and low-resistance crystalline states. The memory cell's reset current can be double a set current, causing peak currents to depend on write data. When all data bits are reset to the amorphous state, a very high peak current is required. To reduce this worst-case peak current, the data is encoded before storage in the PCM cells. An 8/10 encoder adds 2 bits but ensures that no more than half of the data bits are reset. An 8/9 encoder adds an indicator bit, and inverts the 8 bits to ensure that no more than half of the bits are reset. The indicator bit indicates when the 8 bit are inverted, and when the 8 bits are un-inverted. Peak currents are thus reduced by encoding to reduce reset data bits.
摘要:
Peripheral devices store data in non-volatile phase-change memory (PCM). PCM cells have alloy resistors with high-resistance amorphous states and low-resistance crystalline states. The peripheral device can be a Multi-Media Card/Secure Digital (MMC/SD) card. A PCM controller accesses PCM memory devices. Various routines that execute on a CPU in the PCM controller are activated in response to commands in the host-bus transactions. The PCM system increases the throughput of one or more phase-change memory devices by performing one or more of a read-ahead memory operation, a write-ahead memory write operation, a larger page memory write operation, a wider data bus memory write operation, a multi-channel concurrent multi-bank interleaving memory read or write operation, a write-cache memory write operation, and any combination thereof.
摘要:
Phase-change memory (PCM) cells store data using alloy resistors in high-resistance amorphous and low-resistance crystalline states. The time of the memory cell's set-current pulse can be 100 ns, much longer than read or reset times. The write time thus depends on the write data. The very long write-1 time may require wait states. To eliminate wait states for sequential accesses, the PCM cells are divided into 16 banks. Each bank has its own bank write latch that stores data locally at the bank while the bank is being written. Data lines to the banks are freed up to transfer data to other banks once the data is written into the local bank write latch, allowing the long set-current pulse to be applied locally to slowly grow crystals in the alloy resistors. External host data are buffered and applied to the data lines by an array data mux.
摘要:
Peripheral devices store data in non-volatile phase-change memory (PCM). PCM cells have alloy resistors with high-resistance amorphous states and low-resistance crystalline states. The peripheral device can be a Serial AT-Attachment (SATA) or integrated device electronics (IDE) PCM solid-state disk or a Multi-Media Card/Secure Digital (MMC/SD) card. A peripheral PCM controller accesses PCM mass storage devices containing PCM memory chips that form a mass-storage device that is block-addressable rather than randomly-addressable. SATA, IDE, or MMC/SD transactions from a host bus are read by a bus transceiver on the peripheral PCM controller. Various routines that execute on a CPU in the peripheral PCM controller are activated in response to commands in the host-bus transactions. A PCM controller in the peripheral controller transfers data from the bus transceiver to the PCM mass storage devices for storage.
摘要:
Phase-change memory (PCM) cells store data using alloy resistors in high-resistance amorphous and low-resistance crystalline states. The time of the memory cell's set-current pulse can be 100 ns, much longer than read or reset times. The write time thus depends on the write data. The very long write-1 time may require wait states. To eliminate wait states for sequential accesses, the PCM cells are divided into 16 banks. Each bank has its own bank write latch that stores data locally at the bank while the bank is being written. Data lines to the banks are freed up to transfer data to other banks once the data is written into the local bank write latch, allowing the long set-current pulse to be applied locally to slowly grow crystals in the alloy resistors. External host data are buffered and applied to the data lines by an array data mux.