M7270 LSI-11/2 microcomputer module user's guide

This user's guide provides comprehensive information for the Digital Equipment Corporation M7270 LSI-11/2 processor module, a variant of the KD11-HA. The module offers full LSI-11 instruction set, addressing modes, and bus compatibility. A key distinction of the M7270 is its lack of on-board (resident) memory and its inability to generate memory refresh bus signals; it includes a self-initialization circuit for system power-up.

The document details the module's specifications, including its compact physical dimensions and power requirements (+5 V, 1.2 A; +12 V, 0.22 A). It outlines installation procedures, emphasizing the configuration of processor module jumpers (Master Clock Enable, LTC Interrupt, Power-Up Mode Selection) and selection of system backplanes (H9281, H9270, DDV11-B). Four power-up modes are described, allowing for restart via power-up vector, ODT microcode, or a bootstrap program. Essential memory requirements are noted, including the need for "Bank 0" memory (locations 0-17777) for system response during power-up. A minimum system configuration requires the M7270, memory modules, and a console terminal/interface.

The technical description highlights differences from other LSI-11 processors, specifically the absence of resident memory and memory refresh. It delves into the clock pulse and charge pump circuits, the wake-up circuit for self-initialization, BDAL Bus Driver Enable Logic, and DMA arbitration logic. Maintenance instructions include initial checks, running diagnostic programs (requiring 4K R/W memory and a console), and a troubleshooting guide. Appendix A further details the H9281 backplane, covering its installation, power connections, bus signal connections, device priority, and bus terminations.