مدار مجتمع (آی سی) آی سی‌کاربرد ویژه

Product Attributes

Introduction

AM29818A is a high-speed, general-purpose pipeline register with an onboard shadow register for performing Serial Shadow Register (SSR) diagnostics and/or Writable Control Store (WCS) loading. The D-to-Y path provides an 8-bit parallel data path pipeline register for normal system operation. The shadow register can load parallel data to or from the pipeline register and can output data through the D input port (as in WCS loading). The 8-bit shadow register features a multiplexed input that selects parallel input from either the Y port or an adjacent bit in the shadow register, enabling operation as a shift register. In serial shift mode, SDI is shifted into bit position "0" of the shadow register, and the contents of bit position "7" appear at the SDO output. The register can participate in a system-wide serial loop in which normal data address, status, and control registers are replaced by AM29818A diagnostic pipeline registers. This loop can be used to scan in a complete test program starting point (data, address, etc.). After a specified number of clock cycles, the clocked-out data can then be compared against expected results. WCS loading can be accomplished using the same technique. By enabling the D output, instruction words can be serially shifted into the shadow register and written to WCS RAM.

Features

• High-speed non-inverting 8-bit parallel register for any data path or pipeline application
• Writable control store (WCS) pipeline register
• Load WCS from serial register
• Read WCS via serial scan
• Drop-in replacement for SN54/74S818
• High-speed 8-bit "shadow register" with serial shift mode for serial shadow register (SSR) diagnostics
• Controllability: serial scan new machine state
• Observability: serial scan output diagnostic results
• Speed comparable to 'AS374 register

Applications

• Data path applications
• Pipeline applications
• Writable control store loading
• Serial shadow register diagnostics