摘要:
A system comprising a storage location to store information representing a timing parameter pertaining to a random access memory device. An integrated circuit device generates a value that is representative of a period of time that elapses between the random access memory device exiting from a power down mode and a time at which the random access memory device is capable of receiving a command. The integrated circuit device generates the value from the information representing the timing parameter pertaining to the random access memory device.
摘要:
Methods of operation of a memory device and system are provided in embodiments. Initialization operations are conducted at a first frequency of operation during an initialization sequence. Memory access operations are then performed at a second frequency of operation. The second frequency of operation is higher than the first frequency of operation. Also, the memory access operations include a read operation and a write operation. In an embodiment, information that represents the first frequency of operation and the second frequency of operation is read from a serial presence detect device.
摘要:
A lock detection circuit operatively associated with a phase-locked loop indicates when a feedback clock signal is locked to a reference clock signal. The lock detection circuit counts the number of rising and falling edges of the feedback clock signal that are detected between rising edges of the reference clock cycle. The lock detection circuit counts the number of consecutive valid cycles of the reference clock signal during which a single rising edge and a single falling edge of the feedback clock signal are detected. Lock detection circuit asserts a lock signal when the number of consecutive valid cycles counted exceeds a predetermined number. Where the lock detection circuit indicates locked signals and then detects a reference clock cycle that is not valid, lock detection circuit continues to indicate lock if the next reference clock cycle is valid relative to a skewed feedback clock signal.
摘要:
A memory device including an array of memory cells, and a register circuit to store a value representative of a period of time to elapse before the memory device is ready to receive a command when recovering from a power down mode is provided in an embodiment. The command specifies an access to the array of memory cells. A delay lock loop circuit synchronizes data transfers using an external clock signal. The delay lock loop circuit reacquires synchronization with the external clock signal during the period of time.
摘要:
A lock detection circuit operatively associated with a phase-locked loop indicates when a feedback clock signal is locked to a reference clock signal. The lock detection circuit counts the number of rising and falling edges of the feedback clock signal that are detected between rising edges of the reference clock cycle. The lock detection circuit counts the number of consecutive valid cycles of the reference clock signal during which a single rising edge and a single falling edge of the feedback clock signal are detected. Lock detection circuit asserts a lock signal when the number of consecutive valid cycles counted exceeds a predetermined number. Where the lock detection circuit indicates locked signals and then detects a reference clock cycle that is not valid, lock detection circuit continues to indicate lock if the next reference clock cycle is valid relative to a skewed feedback clock signal.
摘要:
The disclosed embodiments related to a clocked memory system which performs a calibration operation at a full-rate frequency to determine a full-rate calibration state that specifies a delay between a clock signal and a corresponding data signal in the clocked memory system. Next, the clocked memory system uses the full-rate calibration state to calculate a sub-rate calibration state, which is associated with a sub-rate frequency (e.g., ½, ¼ or ⅛ of the full-rate frequency). The system then uses this sub-rate calibration state when the clocked memory system is operating at the sub-rate frequency. This calculation of the sub-rate state calibration states eliminates the need to perform an additional time-consuming calibration operation for each sub-rate.
摘要:
A circuit, such as a CDR circuit, includes a sampler to receive a data signal having a variable data bit-rate responsive to a clock signal in an embodiment of the present invention. A clock circuit is coupled to the sampler and generates the clock signal responsive to a selectable update rate and a selectable phase adjust step-size. In a second embodiment of the present invention, the clock circuit includes a Stall logic that is coupled to first, second and third stages and is capable to hold the phase adjust signal responsive to the first and second stage output signals. In a third embodiment of the present invention, an indicator detects the variable data bit-rate and a counter provides the selectable phase adjust step-size for the adjust signal. In a fourth embodiment of the present invention, the clock circuit includes the Stall logic, the indicator and the counter. In a fifth embodiment of the present invention, the clock circuit includes an Averaging circuit to output a phase adjust signal responsive to the averaging of a first and second adjust signals for a predetermined period of time.
摘要:
A lock detection circuit operatively associated with a phase-locked loop indicates when a feedback clock signal is locked to a reference clock signal. The lock detection circuit counts the number of rising and falling edges of the feedback clock signal that are detected between rising edges of the reference clock cycle. The lock detection circuit counts the number of consecutive valid cycles of the reference clock signal during which a single rising edge and a single falling edge of the feedback clock signal are detected. Lock detection circuit uses a state machine to assert a lock signal when the number of consecutive valid cycles counted exceeds a predetermined number. Where the lock detection circuit indicates locked signals and then detects a reference clock cycle that is not valid, the lock detection circuit continues to indicate lock if the next reference clock cycle is valid relative to a skewed feedback clock signal.
摘要:
A lock detection circuit operatively associated with a phase-locked loop indicates when a feedback clock signal is locked to a reference clock signal. The lock detection circuit counts the number of rising and falling edges of the feedback clock signal that are detected between rising edges of the reference clock cycle. The lock detection circuit counts the number of consecutive valid cycles of the reference clock signal during which a single rising edge and a single falling edge of the feedback clock signal are detected. Lock detection circuit uses a state machine to assert a lock signal when the number of consecutive valid cycles counted exceeds a predetermined number. Where the lock detection circuit indicates locked signals and then detects a reference clock cycle that is not valid, lock detection circuit continues to indicate lock if the next reference clock cycle is valid relative to a skewed feedback clock signal.
摘要:
A circuit, such as a CDR circuit, includes a sampler to receive a data signal having a variable data bit-rate responsive to a clock signal in an embodiment of the present invention. A clock circuit is coupled to the sampler and generates the clock signal responsive to a selectable update rate and a selectable phase adjust step-size. In a second embodiment of the present invention, the clock circuit includes a Stall logic that is coupled to first, second and third stages and is capable to hold the phase adjust signal responsive to the first and second stage output signals. In a third embodiment of the present invention, an indicator detects the variable data bit-rate and a counter provides the selectable phase adjust step-size for the adjust signal. In a fourth embodiment of the present invention, the clock circuit includes the Stall logic, the indicator and the counter. In a fifth embodiment of the present invention, the clock circuit includes an Averaging circuit to output a phase adjust signal responsive to the averaging of a first and second adjust signals for a predetermined period of time.