Apparatuses and methods for controlling access to a common bus including a plurality of memory devices coupled to a common bus, wherein individual ones of the plurality of memory devices are configured to access the common bus responsive to a strobe signal, and a strobe line driver programmed with a first delay associated with a combination of a first command type and a first one of the plurality of memory devices to provide a first strobe signal to the first one of the plurality of memory devices, and further programmed with a second delay associated with a combination of a second command type and a second one of the plurality of memory devices to provide a second strobe signal to the second one of the plurality of memory devices.

A system on chip is provided. The system on chip includes a bus including a data channel through which data is transmitted in at least one direction and a master interface configured to receive first data from the data channel, perform a bit operation on the first data and on second data input before input of the first data, determine an encoding operation for the first data based on a result of the bit operation, perform the encoding operation on the first data, to obtain encoded data, and provide the encoded data and a transformation signal indicating the encoding operation to the data channel.

Dynamic bus inversion (DBI) for programmable levels of a ratio of ones and zeros. A transmitting device identifies a number and/or ratio of ones and zeros in a noninverted version of a signal to be transmitted (noninverted signal) and a number and/or ratio of ones and zeros in an inverted version of the signal (inverted signal). The transmitting device can calculate whether a difference of ones and zeros in the noninverted signal or a difference of ones and zeros in the inverted signal provides a calculated average ratio of ones to zeros closer to a target ratio. The transmitting device sends the signal that achieves provides the calculated average ratio closer to the target ratio.

A system and method for conveying data include the capability to determine whether a transaction request credit has been received at a computer module, the transaction request credit indicating that at least a portion of a transaction request message may be sent. The system and method also include the capability to determine, of a transaction request message is to be sent, whether at least a portion of the transaction request message may be sent and to send the at least a portion of the transaction request message if it may be sent.

A communications control system is disclosed that includes a serial communications interface and a parallel communications interface for coupling a plurality of input/output modules with a control module. The serial communications interface is configured for connecting the plurality of input/output modules to the control module in parallel to transmit information between the plurality of input/output modules and the control module, and the parallel communications interface is configured for separately connecting the plurality of input/output modules to the control module to transmit information between the plurality of input/output modules and the control module, and to transmit information between individual ones of the plurality of input/output modules. The serial communications interface may comprise a multidrop bus, and the parallel communications interface may comprise a cross switch.

A method is provided that compensates for misalignment on a synchronous data bus. The method includes: replicating propagation path lengths, loads, and buffering of a radial distribution network for a strobe; receiving a first signal, and generating a second signal by employing the replicated propagation path lengths, loads, and buffering; when an update signal is asserted, when an update signal is asserted, measuring a propagation time beginning with assertion of the first signal and ending with assertion of the second signal by selecting one of a plurality of successively delayed versions of the first signal that coincides with the assertion of the second signal, wherein said selecting comprises incrementing and decrementing bus states of select inputs on a mux, wherein the plurality of successively delayed versions of the first signal comprises inputs to the mux; gray encoding a value on a lag bus that indicates the propagation time; and receiving one of a plurality of radially distributed strobes and a data bit, and delaying registering of the data bit by the propagation time. The receiving includes generating successively delayed versions of the data bit; receiving the value on the lag bus, and selecting one of the successively delayed versions of the data bit that corresponds to the value; and registering the state of the one of the successively delayed versions of the data bit upon assertion of one of a plurality of radially distributed strobe signals.

An apparatus is provided that compensates for misalignment on a synchronous data bus. The apparatus includes a replica radial distribution element, a bit lag control element, and a synchronous lag receiver. The replica radial distribution element is configured to receive a first signal, and is configured to generate a second signal, where the replica radial distribution element comprises replicated propagation path lengths, loads, and buffering of a radial distribution network for a strobe. The bit lag control element is configured to measure a propagation time beginning with assertion of the first signal and ending with assertion of the second signal, and is configured to generate a value on a lag bus that indicates the propagation time. The bit lag control element has delay lock control and a gray encoder. The delay lock control is configured to select one of a plurality of successively delayed versions of the first signal that coincides with the assertion of the second signal, where the delay lock control selects the one of a plurality of successively delayed versions of the first signal by incrementing and decrementing bus states of select inputs on a first mux, and where the plurality of successively delayed versions of the first signal comprises inputs to the first mux, and where the plurality of successively delayed versions comprises outputs of a first plurality of series-coupled matched inverter pairs. The gray encoder is configured to gray encode the propagation time to generate the value on the lag bus. The synchronous lag receiver is configured to receive one of a plurality of radially distributed strobes and a data bit, and is configured to delay registering of the data bit by the propagation time. The synchronous lag receiver includes a second plurality of series-coupled matched inverter pairs, a second mux, and a bit receiver. The second plurality of series-coupled matched inverter pairs is configured to generate successively delayed versions of the data bit. The second mux is coupled to the second plurality of series-coupled matched inverter pairs, is configured to receive the value on the lag bus, and is configured to select one of the successively delayed versions of the data bit that corresponds to the value. The bit receiver is configured to receive the one of the successively delayed versions of the data bit and one of a plurality of radially distributed strobe signals, and is configured to register the state of the one of the successively delayed versions of the data bit upon assertion of the one of a plurality of radially distributed strobe signals.

An apparatus is provided that compensates for misalignment on a synchronous data bus. The apparatus includes a replica radial distribution element, a Joint Test Action Group (JTAG) interface, and a bit lag control element. The replica radial distribution element is configured to receive a lag pulse signal, and is configured to generate a replicated strobe signal, where the replica radial distribution network includes replicated propagation path lengths, loads, and buffering of a radial distribution network for a strobe. The JTAG interface is configured to receive control information over a standard JTAG bus, where the control information indicates an amount to adjust a propagation time. The bit lag control element is configured to measure the propagation time beginning with assertion of the first signal and ending with assertion of the second signal, and is configured to generate a first value on a lag bus that indicates an adjusted propagation time. The bit lag control element includes delay lock control, adjust logic, and a gray encoder. The delay lock control is configured to select one of a plurality of successively delayed versions of the first signal that coincides with the assertion the second signal, and is configured to generate a second value on a lag select bus that indicates the propagation time, where the delay lock control selects the one of a plurality of successively delayed versions of the first signal by incrementing and decrementing bus states of select inputs on a mux, and where the plurality of successively delayed versions includes inputs to the mux, and where the plurality of successively delayed versions includes outputs a first plurality of series-coupled matched inverter pairs. The adjust logic is coupled to the JTAG interface and to the lag select bus, and is configured adjust the second value by the amount prescribed by the JTAG interface to yield a third value that is output to an adjusted lag bus. The gray encoder is configured to gray encode the third value to generate the first value on the lag bus.

An apparatus is provided that compensates for misalignment on a synchronous data bus. The apparatus includes a replica radial distribution element, a Joint Test Action Group (JTAG) interface, and a bit lag control element. The replica radial distribution element is configured to receive a lag pulse signal, and is configured to generate a replicated strobe signal, where the replica radial distribution network includes replicated propagation path lengths, loads, and buffering of a radial distribution network for a strobe. The JTAG interface is configured to receive control information over a standard JTAG bus, where the control information indicates an amount to adjust a propagation time. The bit lag control element is configured to measure, when an update signal is asserted, the propagation time beginning with assertion of the first signal and ending with assertion of the second signal, and is configured to generate a first value on a lag bus that indicates an adjusted propagation time. The bit lag control element includes delay lock control, adjust logic, and a gray encoder. The delay lock control is configured to select one of a plurality of successively delayed versions of the first signal that coincides with the assertion the second signal, and is configured to generate a second value on a lag select bus that indicates the propagation time, where the delay lock control selects the one of a plurality of successively delayed versions of the first signal by incrementing and decrementing bus states of select inputs on a mux, and where the plurality of successively delayed versions includes inputs to the mux, and where the plurality of successively delayed versions includes outputs a first plurality of series-coupled matched inverter pairs. The adjust logic is coupled to the JTAG interface and to the lag select bus, and is configured adjust the second value by the amount prescribed by the JTAG interface to yield a third value that is output to an adjusted lag bus. The gray encoder is configured to gray encode the third value to generate the first value on the lag bus.

An apparatus is provided that compensates for misalignment on a synchronous data bus. The apparatus includes a replica radial distribution element, a bit lag control element, and a synchronous lag receiver. The replica radial distribution element is configured to receive a lag pulse signal, and is configured to generate a replicated strobe signal, where the replica radial distribution network comprises replicated propagation path lengths, loads, and buffering of a radial distribution network for a strobe. The bit lag control element is configured to measure the time between assertion of the lag pulse signal and assertion of the replicated strobe signal when an update signal is asserted, and is configured to generate a first value on a lag bus that indicates the time. The bit lag control element has delay lock control that is configured to select one of a plurality of successively delayed versions of the lag pulse signal that coincides with the assertion the replicated strobe signal, and is configured to generate a second value on a lag select bus that indicates the propagation time, where the delay lock control selects the one of a plurality of successively delayed versions of the lag pulse signal by incrementing and decrementing bus states of select inputs on a mux, and where the plurality of successively delayed versions comprises inputs to the mux. The synchronous lag receiver is coupled to the bit lag control element, and is configured to receive a first one of a plurality of radially distributed strobes and a data bit, and is configured to delay registering of the data bit by the time.