The DP8216/DP8216M and DP8226/DP8226M are 4-bit bidirectional bus drivers to use in bus-oriented applications. The non-inverting DP8216/DP8216M and inverting DP8226/DP8226M drivers are provided for flexibility in system design. Each buffered line of the four-bit drivers consists of two separate buffers that are TRI-STATE… to achieve direct bus interface and bidirectional capability. On one side of the driver the output of one buffer and the input of another are tied together (DB); this side is used to interface to the system side components such as memories, I/O, etc. because its interface is TTL compatible and has a high drive capability (50mA). On the other side of the driver, the inputs and outputs are separated to provide maximum flexibility. Of course, they can be tied together so that the driver can be used to buffer a true bidirectional bus. The DO outputs on this side of the driver have a special high voltage output drive capability so that direct interface to the 8080 type CPUs is achieved with an adequate amount of noise immunity. The CS input is a device enable. When it is ‘‘high’’ the output drivers are all forced to their high-impedance state. When it is a ‘‘low’’ the device is enabled and the direction of the data flow is determined by the DIEN input. The DIEN input controls the direction of data flow, which is accomplished by forcing one of the pair of buffers into its high-impedance state and allowing the other to transmit its data. A simple two-gate circuit is used for this function.
