| 摘要 |
<p>A Class A node comprising a slave bus controller circuit (SBCC) operates as a remote input/output device for performing Class A communications for a master Class B node over an interconnecting SAE J1850 or similar network (104). The SBCC (102) receives messages from one or more Class B nodes to receive output data which appear at one or more output ports of the SBCC. Output data may be directly provided or may be combined with mask data such that only mask selected bits of the output data are passed to the one or more output ports of the SBCC. Input data directly connected to one or more input ports of the SBCC are transmitted back to a master node as an in-message response of the network. The SBCC provides inexpensive Class A communications using the SAE J1850 protocol which is primarily intended for Class B communications. The SBCC is inexpensive because of its simplified circuitry, its ability to operate without a controlling processor and, in some embodiments, the implementation of its master clock as an RC oscillator (182) which does not directly determine bit timing for the SBCC but is used to measure the bit timing of the master node from which it is receiving messages.</p> |
