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Interface for Writing Subaddressing Data to Non-Volatile Random Access Memory through Setup

IP.com Disclosure Number: IPCOM000113421D
Original Publication Date: 1994-Aug-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 4 page(s) / 143K

Publishing Venue

IBM

Related People

Milling, D: AUTHOR [+2]

Abstract

Described are changes required in the Setup routine to access subaddressing data, which is passed to Setup through the Adapter Descriptor File (ADF), and to write this data to Non-Volatile Random Access Memory (NVRAM). To support subaddressing, two new keywords have been added to the ADF---SubAddr and SubAddrSize. These keywords are used to describe the Programmable Option Select (POS) bytes to be written to NVRAM. Setup takes the information passed through the keywords, verifies it, and writes it to NVRAM in the format expected by Power-On Self Test (POST). To provide this interface through Setup, first the code which parses the ADF file must be changed to accept and interpret the new addressing keywords.

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This is the abbreviated version, containing approximately 38% of the total text.

Interface for Writing Subaddressing Data to Non-Volatile Random Access
Memory through Setup

      Described are changes required in the Setup routine to access
subaddressing data, which is passed to Setup through the Adapter
Descriptor File (ADF), and to write this data to Non-Volatile Random
Access Memory (NVRAM).  To support subaddressing, two new keywords
have been added to the ADF---SubAddr and SubAddrSize.  These keywords
are used to describe the Programmable Option Select (POS) bytes to be
written to NVRAM.  Setup takes the information passed through the
keywords, verifies it, and writes it to NVRAM in the format expected
by Power-On Self Test (POST).  To provide this interface through
Setup, first the code which parses the ADF file must be changed to
accept and interpret the new addressing keywords.

Without this feature, a typical ADF file has the following structure:
  AdapterId 0FFFFh
  AdapterName "Typical Adapter"
  NumBytes 2
  NamedItem
         Prompt "Communications Port"
       choice "SDLC_1, Arb 1"   pos[0]=11110001b pos[1]=11110001b
                           io 0380h-038fh  int 3 4  arb 1
       choice "SDLC_1, Arb 7"   pos[0]=XXX1000Xb pos[1]=XXXX0111b
                           io 0380h-038fh  int 3 4  arb 7
                           .
                           .
                           .

      In this example, the NumBytes field indicates the number of POS
bytes used by the adapter, and the POS keywords shown under the
choice item indicate the possible POS values.

      Without the subaddressing feature, the Micro Channel*
architecture allows only four POS registers, limiting the number of
possible different adapter configuration options.  This limitation is
overcome by providing the subaddressing feature, with necessary
changes in the BIOS, POST, and Setup code.  For adapters using
subaddressing, the structure listed above changes as follows:
    AdapterId 0FFFFh
    AdapterName "Typical Adapter"
    SubAddrSize 24 1
    NamedItem
           Prompt "Communications Port"
         choice "SDLC_1, Arb 1"   pos[0]=11110001b pos[1]=11110001b
                             pos[2]=11110001b pos[1]=11110001b
                             subaddr[0]=0f2h
                             subaddr[1]=0f3h
                             subaddr[2]=11110100b
                             subaddr[3]=0f5h
                             .

      The SubAddrSize keyword in this example first lists the count
of subaddress bytes, including the flag byte.  The number of POS
bytes is always four when subaddressing is used, and thus is not
included in this count.  Th...