MCA Data Transfer Procedures

Source: SA23-2647-00 RS/6000 Hardware Technical Reference - Micro Channel Architecture, 1st Ed., 1990

Note: Pat Bowld's book "Micro Channel Architecture - Revolution in Personal Computing" is NOT on the Internet Archive or Google Books. But... SA23-2647-00 looks to be the / a source document that she pulled quite a bit of text from. The PS/2 and RS/6000 both use MCA, but the RS/6000 system uses a byte-order that is the reverse of the PS/2, so it has to reverse the byte order when using the MCA bus. BUT... once the poodle-faking is done, both systems use the Holy Bus... v/r, LFO


The data transfer procedures are used to transfer data between a controlling master and the selected slave. The three types of data transfer procedures are:

Each procedure defines the signal sequences and the signal timing specifications used in the procedure. Data transfer occurs only during the data transfer cycle defined by the procedure. A cycle is one or more data transfers, occurring during the time between the leading edge of -CMD and the trailing edge of -CMD. The data transfer cycle address selects either an I/O-address-space address or a memory-address-space address, under the control of M/-IO.

A controlling master or a DMA slave can drive -BURST, to indicate to the central arbitration control point that one or more data transfer cycles will be used before the EOT occurs. Refer to "Burst Transfer" on page 1-25 for more information. This section describes each procedure, the signal sequence for each procedure and the signal timing specifications.

The system technical manuals contain the signal sequence and timing specifications for matched-memory signals and auxiliary-video signals.

Exception condition handling and reporting descriptions are contained in "Exception Condition Reporting and Handling" on page 1-83.

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