FUNCTIONAL DESCRIPTION

The LH543611 and LH543621 contain two FIFO buffers, FIFO #1 and FIFO #2. These operate in parallel, but in opposite directions, for bidirectional data buffering. FIFO #1 and FIFO #2 each are organized as 512 or 1024 by 36 bits. The LH543611 and LH543621 are ideal either for wide unidirectional applications or for bidirectional data applications; component count and board area are reduced.

FEATURES

• Pin-Compatible and Functionally Upwards-Compatible with Sharp LH5420 and LH543601, but Deeper

• Expanded Control Register that is Fully Readable as well as Writeable

• Fast Cycle Times: 18/20/25/30/35 ns

• Improved Input Setup and Flag Out Timing

• Two 512 × 36-bit FIFO Buffers (LH543611) or Two 1024 × 36-bit FIFO Buffers (LH543621)

• Full 36-bit Word Width

• Selectable 36/18/9-bit Word Width on Port B; Selection May be Changed Without Resetting the BiFIFO

• Programmable Byte-Order Reversal – ‘Big-Endian ↔ Little-Endian Conversion’

• Independently-Synchronized (‘Fully-Asynchronous’) Operation of Port A and Port B

• ‘Synchronous’ Enable-Plus-Clock Control at Both Ports

• R/W, Enable, Request, and Address Control Inputs are Sampled on the Rising Clock Edge

• Synchronous Request/Acknowledge ‘Handshake’ Capability; Use is Optional

• Device Comes Up Into a Known Default State at Reset; Programming is Allowed, but is not Required

• Asynchronous Output Enables

• Five Status Flags per Port: Full, Almost-Full, Half-Full, Almost-Empty, and Empty

• All Flags are Independently Programmable for Either Synchronous or Asynchronous Operation

• Almost-Full Flag and Almost-Empty Flag Have Programmable Offsets

• Mailbox Registers with Synchronized Flags

• Data-Bypass Function

• Data-Retransmit Function

• Automatic Byte Parity Checking with Programmable Parity Flag Latch

• Programmable Byte Parity Generation

• Programmable Byte, Half-Word, or Full-Word Oriented Parity Operations

• 8 mA-IOL High-Drive Three-State Outputs with Built-In Series Resistor

• TTL/CMOS-Compatible I/O

• Space-Saving PQFP and TQFP Packages