摘要:
A method is disclosed comprising detecting an edge-transition of a strobe signal using hysteresis, the strobe signal originating in a first clock domain. A count is controlled in a first direction in response to the detected edge-transition. The count is controlled in a second direction in response to an edge-transition of a clock signal, the clock signal originating in a second clock domain. Data is interfaced between the first and second clock domains in response to the count.
摘要:
Self-timed interfaces and methods for interfacing different timing domains. These self-timed interfaces receive a strobe signal from a component operating under a first clock domain. A first signal path of the self-timed interface couples the strobe signal to a receiver that samples data of data line under control of the strobe signal. A second signal path of the self-timed interface couples the strobe signal to an interface circuit through a hysteresis-based element. The interface circuit, under control of an output of the hysteresis-based element along with a clock signal that originates under a second clock domain, generates an interface enable signal for use in controlling data transfers between the different clock domains.
摘要:
A method is disclosed comprising detecting an edge-transition of a strobe signal using hysteresis, the strobe signal originating in a first clock domain. A count is controlled in a first direction in response to the detected edge-transition. The count is controlled in a second direction in response to an edge-transition of a clock signal, the clock signal originating in a second clock domain. Data is interfaced between the first and second clock domains in response to the count.
摘要:
A receiver includes a continuous-time equalizer, a decision-feedback equalizer (DFE), data and error sampling logic, and an adaptation engine. The receiver corrects for inter-symbol interference (ISI) associated with the most recent data symbol (first post cursor ISI) by establishing appropriate equalization settings for the continuous-time equalizer based upon a measure of the first-post-cursor ISI.
摘要:
A memory controller for strobe-based memory systems is disclosed. The memory controller includes a circuit to generate a control signal having a predetermined timing relationship with respect to a first clock signal, a circuit to receive the control signal, and a receiver to sample the read data in response to the qualified read strobe signal. The receiving circuit includes an input to receive an external read strobe signal transmitted by a semiconductor memory device, circuitry to synchronize the control signal and the received read strobe signal to have a common timing relationship with respect to each other, and circuitry to gate the read strobe signal based on the synchronized control signal.
摘要:
Embodiments of an apparatus that uses unused masked data bits during an access to a memory are described. This apparatus includes a selection circuit, which selects data bits to be driven on data lines during the access to the memory. This selection circuit includes a control input that receives a data mask signal, which indicates whether a set of data bits is to be masked during the access to the memory. During the access to the memory, the selection circuit selects either the set of data bits to be driven when the data mask signal is not asserted, or an alternative set of values to be driven when the data mask signal is asserted.
摘要:
A memory system includes a memory controller that issues command signals and a reference-clock signal to a memory device. The edge rate of the reference-clock signal is lower than the bit rate of the command signals, so the memory device multiplies the reference clock signal to develop a command-recovery clock signal with which to sample the incoming command signals. The memory controller issues the command signals as a series of multi-bit command words aligned with edges of the reference-clock signal so that the memory device can use edges of the reference clock signal for command-word alignment.
摘要:
A system and method for performing clock and data recovery. The system sets the phase of a recovered clock signal 30 according to at least three estimates of the rate of change of an offset between the frequency of the data transmitter clock and the frequency of a receiver clock 15.
摘要:
Embodiments of a system that communicates bidirectional data between two devices via shared links is described. In this system, data is transmitted on the shared links by one of the devices using single-ended drivers, and corresponding symbols are received on the shared links by the other device using differential comparison circuits. The data may be encoded as a series of parallel codewords prior to transmission. Each shared link may communicate a respective symbol in each codeword, which can have one of two possible logical values (e.g., a logic 0 or a logic 1). The corresponding symbols received by the other device may comprise a parallel symbol set, and each of the differential comparison circuits may compare symbols received on pairs of the shared links. A decoder in the other device may decode a respective parallel symbol set from the outputs of the differential comparison circuits to recover the encoded data.
摘要:
A method and apparatus for transferring data across a clock domain boundary is described. In one embodiment, a fixed relationship between a faster clock and a slower clock is maintained in the process of phase alignment to allow great flexibility in allowable combinations of slower clock and faster clock frequencies. In one embodiment, an encoded edge select word is generated once at system initialization and used thereafter to select edges of the faster clock on which to sample data that comes from the clock domain of the slower clock. The value of the encoded edge select word is based, in part, on the fixed relationship between the faster clock and the slower clock.