Micro Channel Architecture

Micro Channel Architecture, also known as MCA, Microchannel, or Low-End Parallel Bus - Family 2 (LEPB) [1], is the expansion bus used in the Personal System/2 line of computers (Model 50 and up), its Japanese counterpart - the Personal System/55 line, older RS/6000 and PC Server machines and a few other IBM products. It was also used in selected computers manufactured by Tandy, Reply, ALR, NCR, Olivetti, Apricot, and other OEMs.

The links below cover various technical aspects of the architecture, compare it with competing bus designs, and provide other contextual information.

MCA Slot Types (16/32-bit, BVE, AVE, MME extensions)
MCA Slot Pinouts
Processor Complex Pinout
MCA Data Transfers (10, 20, 40, 80, 160 MB/s modes)
MCA Data Transfer Procedures
   Basic Transfer
   Streaming Transfer
   DMA Transfer
MCA Interrupt Procedures
MCA Features (Streaming, Address and Data Parity, Synchronous Exception Signaling)
Auxiliary Video Extension (AVE)
MCA Benefits Adapter mounting and grounding

Micro Channel Bus Tutorial (by Eric Schlaepfer)

Why MCA?
Bus Evolution
System Bus or System Bottleneck? Whatever happened to EISA and the Micro Channel?
How PC/XT/AT Cards Can Prohibit Interrupt Sharing
The Micro Channel versus the AT Bus
Comparing IBM's Micro Channel and Apple's NuBus
PC Bus Performance NuBus vs Micro Channel
PCI/Micro Channel White Paper (PCI/MCA comparison by IBM)
MCA: The Sacrificial Lion
IBM's Micro Channel
Programmable Device Masters the Art of High-Speed Data Transfers (Altera's EPLD w/ SDP)
PS/2 Model 50 - Under The Cover (BYTE article focused on MCA)
The 32-bit Micro Channel (BYTE, Oct 1987)
GUESS - The Network Is The Message (Chet's cluster computer card)

Subsystem Control Block (SCB) An Architecture for Micro Channel Bus Masters

System Setup (POS for Adapters and System Board)
Planar POS Registers (Server 95)
Programmable Option Select Operation
About ADF Files

Checking for Micro Channel Bus
Retrieving IDs of Installed Adapters
Finding an Adapter's Slot Number
Retrieving the Planar ID
List of Known Planar IDs

mca_32.c / mca.h MCA Support in Linux Kernel (C source files)
setup.S Obtains system data from BIOS; Linux Kernel (x86 ASM)

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Last update: 05 Oct 2022 - Changelog | Legal Info & Contact