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| 74LCX16646 |
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 FAIRCHILD
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4 page 
www.fairchildsemi.com 4 Functional Description In the transceiver mode, data present at the HIGH imped- ance port may be stored in either the A or B register or both. The select (SABn, SBAn) controls can multiplex stored and real-time. The examples shown below demon- strate the four fundamental bus-management functions that can be performed. The direction control (DIRn) determines which bus will receive data when OEn is LOW. In the isolation mode (OEn HIGH), A data may be stored in one register and/or B data may be stored in the other register. When an output func- tion is disabled, the input function is still enabled and may be used to store and transmit data. Only one of the two busses, A or B, may be driven at a time. Real-Time Transfer Bus B to Bus A Real-Time Transfer Bus A to Bus B Transfer Storage Data to A or B Storage OE DIR CPAB CPBA SAB SBA LL X X X L OE DIR CPAB CPBA SAB SBA LH X X L X OE DIR CPAB CPBA SAB SBA LL X H or L X H LH H or L X H X OE DIR CPAB CPBA SAB SBA LH XL X LX X XL HX XX X HX X XX |
