Browse Prior Art Database

Serial Link Communication Module for Local Work Station Attachments

IP.com Disclosure Number: IPCOM000047391D
Original Publication Date: 1983-Nov-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 2 page(s) / 57K

Publishing Venue

IBM

Related People

Stockwell, DA: AUTHOR

Abstract

This article describes a Serial Link Communication Module (SLM) with a number of modes that are used to select the level of link protocol and error recovery appropriate to primary stations, protocol interactive secondary stations and protocol transparent secondary stations. See Figs. 1 and 2. In the primary station use, the SLM 10 provides hardware assist to the primary microprocessor 12, consisting of auto poll from command list, SDLC (synchronous data link control) address generation and checking, frame count generation and checking, and idle detect time out. A variable number of devices can be polled under auto poll, and the auto poll can be terminated by either SLM 10 or microprocessor 12. The idle detect time out in SLM 10 provides for automatic retry of a frame transmission.

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Serial Link Communication Module for Local Work Station Attachments

This article describes a Serial Link Communication Module (SLM) with a number of modes that are used to select the level of link protocol and error recovery appropriate to primary stations, protocol interactive secondary stations and protocol transparent secondary stations. See Figs. 1 and 2. In the primary station use, the SLM 10 provides hardware assist to the primary microprocessor 12, consisting of auto poll from command list, SDLC (synchronous data link control) address generation and checking, frame count generation and checking, and idle detect time out. A variable number of devices can be polled under auto poll, and the auto poll can be terminated by either SLM 10 or microprocessor 12. The idle detect time out in SLM 10 provides for automatic retry of a frame transmission. Once the time-out register's value is loaded by microprocessor 12, it is used for all auto polled secondaries 14, 16, 18, 20. In non-intelligent secondary stations, the SLM 10' handles all of the link protocol, allowing attachment of devices without any processor. This allows attachment of very low cost peripherals. When used with a non-intelligent secondary, the SLM uses default internal register values at power-on.

These default values can be modified by the primary station at any time using a command over the serial link. An ordered register structure local and link grouping along with link address loading under hard...