摘要:
A method and apparatus for automated calibration of I/O over a multi-variable eye window is provided. A transmitter may conduct data transmissions to a receiver of an integrated circuit (IC) over a plurality of signal lines. The data transmissions may be conducted according to a certain parameters or sets of parameters. Parameters may include voltage levels at which signals are transmitted or timing delays. The receiver may determine whether the correct data value was received over each signal line. The results may be recorded in a storage mechanism in the same IC as the receiver. The storage mechanism may, for each signal line, store a pass/fail result corresponding to the particular parameters for the data transmission. The system may select the parameters which subsequent transmissions are to be conducted over each of the plurality of signal lines from the storage mechanism.
摘要:
A method and apparatus for automated calibration of I/O over a multi-variable eye window is provided. A transmitter may conduct data transmissions to a receiver of an integrated circuit (IC) over a plurality of signal lines. The data transmissions may be conducted according to a certain parameters or sets of parameters. Parameters may include voltage levels at which signals are transmitted or timing delays. The receiver may determine whether the correct data value was received over each signal line. The results may be recorded in a storage mechanism in the same IC as the receiver. The storage mechanism may, for each signal line, store a pass/fail result corresponding to the particular parameters for the data transmission. The system may select the parameters which subsequent transmissions are to be conducted over each of the plurality of signal lines from the storage mechanism.
摘要:
A method and apparatus for automated calibration of I/O over a multi-variable eye window is provided. A transmitter may conduct data transmissions to a receiver of an integrated circuit (IC) over a plurality of signal lines. The data transmissions may be conducted according to a certain parameters or sets of parameters. Parameters may include voltage levels at which signals are transmitted or timing delays. The receiver may determine whether the correct data value was received over each signal line. The results may be recorded in a storage mechanism in the same IC as the receiver. The storage mechanism may, for each signal line, store a pass/fail result corresponding to the particular parameters for the data transmission. The system may select the parameters which subsequent transmissions are to be conducted over each of the plurality of signal lines from the storage mechanism.
摘要:
A method and apparatus for operating a source synchronous receiver. In one embodiment, a source synchronous receiver may include a clock receiver comprising a clock detector and a clock signal buffer. The clock detector may be configured to detect a first clock signal and assert a clock detect signal responsive to detecting the first clock signal. The clock buffer may receive the first clock signal and produce a second clock signal, which may be driven to a digital locked loop (DLL) circuit, where the second clock signal is regenerated and driven to a data buffer of the source synchronous receiver. The clock detect signal may be received by a clock verification circuit. The clock verification circuit may be configured to initiate a reset of the source synchronous receiver upon a failure to receive the clock detect signal. The resetting of the source synchronous receiver may be performed locally, and does not reset the core logic of the device in which it is implemented, nor any other source synchronous port on the device. Thus, other source synchronous ports on the device, as well as the core logic, may be able to continue operations as normal. The method and apparatus may include a source synchronous receiver that is hot-swappable.
摘要:
A source synchronous test methodology and apparatus. In one embodiment, an integrated circuit (IC) configured for source synchronous I/O transactions may be a device under test (DUT) and may be mounted to a load board for testing. The load board may be electrically coupled to a test system. The test system may shift first test data into a first IC on the load board. The first chip may then transmit the first test data through a source synchronous line, or a source synchronous link having a plurality of lines, to a second IC. Second test data produced responsive to the source synchronous transmission is then shifted from the second IC to the tester. The second test data is then analyzed. The analysis may comprise comparing the second data to expected data, and/or may also comprise analyzing the second data with respect to an eye window.
摘要:
A clock divider circuit having a fifty per cent duty cycle and multiple integer ratios for dividing an input clock signal. In one embodiment, a clock divider circuit may include a chain of serially-coupled flip-flops. The chain may include at least a first and a second flip-flop, both of which may be triggered by a first edge of an input clock signal. A third flip-flop, coupled to (but not part of) the chain may be configured to be triggered by a second edge of the input clock signal. The third flip-flop may be coupled to an output circuit. In addition to receiving the output signal from the third flip-flop, the output circuit may also receive signals from the chain of serially-coupled flip-flops. The output circuit may drive a second clock signal, which may be produced by dividing the first clock signal based upon the signals it receives. The first clock signal may be divided by an even or an odd integer ratio, or may be divided by an integer ratio (e.g. 2.5), although clock signals produced based on a decimal ratio may have a duty cycle that is not fifty per cent.