Abstract: A circuit embodied in a single integrated circuit, which is connected through an asynchronous communication bus to a primary bus master and a permanent bus slave, cooperates with the master and slave in a multi-master transfer of a block of data having a leading sub-block of data followed by a trailing sub-block of data. The slave operates in accord with request/acknowledge protocol by applying at least one request signal to a conductor of the bus and responding to each of a consecutive sequence of acknowledge signals on a second conductor of the bus from the master in communication of each of a consecutive sequence of concurrently-applied parallel-by-bit data carried by multiple other conductors that define a data bus portion of the communication bus.