GENERAL DESCRIPTION
The Enhanced SCSI-2 Controller (ESC) was designed to support Fast SCSI-2 transfer rates of up to 10 Mbytes/s in synchronous mode and up to 7 Mbytes/s in the asynchronous mode. The ESC is downward compatible with the Am53C94/96, combining its functionality with features such as Fast SCSI, programmable Active Negation, a 24-bit transfer counter, and a part-unique ID code containing manufacturer and serial # information.

DISTINCTIVE CHARACTERISTICS
■ Pin/function compatible with Emulex FAS216/236
■ AMD’s Patented programmable GLITCH EATERTM Circuitry on REQ and ACK inputs
■ 10 Mbytes/s synchronous Fast SCSI transfer rate
■ 20 Mbytes/s DMA transfer rate
■ 16-Bit DMA interface plus 2 bits of parity
■ Flexible three bus architecture
■ Single-ended SCSI bus supported by Am53CF94
■ Differential SCSI bus supported by Am53CF96
■ Selection of multiplexed or non-multiplexed address and data bus
■ High current drivers (48 mA) for direct connection to the single-ended SCSI bus
■ Supports Disconnect and Reselect commands
■ Supports burst mode DMA operation with a threshold of eight
■ Supports 3-byte tagged-queueing as per the SCSI-2 specification
■ Supports group 2 and 5 command recognition as per the SCSI-2 specification
■ Advanced CMOS process for lower power consumption
■ AMD’s exclusive programmable power-down feature
■ 24-Bit extended transfer counter allows for data block transfer of up to 16 Mbytes
■ Independently programmable 3-byte message and group 2 identification
■ Additional check for ID message during bus-initiated Select with ATN
■ Reselection has QTAG features of ATN3
■ Access FIFO Command
■ Delayed enable signal for differential drivers avoid contention on SCSI differential lines
■ Programmable Active Negation on REQ, ACK and Data lines
■ Register programmable control of assertion/deassertion delay for REQ and ACK lines
■ Part-unique ID code
■ Am53CF94 available in 84-pin PLCC package
■ Am53CF96 available in 100-pin PQFP package
■ Am53CF94 available in 3.3 V version
■ Supports clock operating frequencies from 10 MHz–40 MHz
■ Supports Scatter-Gather or Back-to-Back synchronous data transfers