SN74ACT2440

• Designed for NuBusE Interface Applications
• Supports Master, Slave, and Master/Slave Applications
• Conforms to ANSI/IEEE Std 1196-1987
• Designed to Operate With SN74BCT2420 NuBus^TM Data/Address Interface Devices
• Supports NuBus^TM 1987 Block Transfers With the Addition of the SN74ALS2442
• EPIC^TM (Enhanced Performance Implanted CMOS) 1-m Process
• Fully TTL-Compatible
• Dependable Texas Instruments Quality and Reliability

The SN74ACT2440 NuBus^TM Controller handles NuBusE signaling protocol in compliance with ANSI/IEEE Std 1196-1987. The device allows a simple connection to the NuBus^TM; typical configurations include master-only, slave-only, and master/slave. Additionally, it provides extra status and control lines to facilitate more sophisticated approaches. With the addition of the SN74ALS2442, slave block transfers can be supported by this device. For additional details on block transfers, consult the SN74ALS2442 data sheet and the application note titled Supporting NuBusE Block Slave Transfers Using Texas Instruments 'ACT2440.

Figure 1 shows a typical NuBus^TM interface using the 'ACT2440. Data and address buffering is handled via two SN74BCT2420s. The SN74BCT2420s are BiCMOS buffers designed specifically for supporting NuBus^TM interfacing. The 'ACT2440 provides the buffer control signals needed to directly drive the SN74BCT2420s; however, in simpler applications, standard SSI and MSI buffers may be used in place of the 'BCT2420s.

The 'ACT2440 is comprised of five major signal groups: byte decode signals, data/address interface-control signals, master/slave input signals, NuBus^TM card-slot signals, and NuBus^TM status signals. Byte decode determines which type of NuBus^TM cycle is being performed. Data/address interface control provides the buffering signals required to multiplex and de-multiplex the NuBus^TM data/address lines. The master/slave inputs control the master- and slave-state machines. The NuBusE card-slot signals interface with the NuBus^TM. The NuBus^TM status signals indicate the status of the master/slave-state machines and provide buffered NuBus^TM signals. Refer to Table 1 for additional details.

The'ACT2440 is characterized for operation from 0°C to 70°C.