The ISAPNP.CONF.5 manual

Dated 15 Oct 1999


isapnp.conf - File format used by isapnp.




The isapnp.conf file is a configuration file for isapnp. isapnp.conf provides instructions for isapnp. This includes how to identify the cards present, and configuration information for each one.


The file consists of comments and instructions.

Comments start with a # character, and continue to the end of the line.

Instructions consist of keywords and parameters, enclosed in pairs of parentheses, with nesting as appropriate to show context. For example:

 (CONFIGURE DFX0000/1493 (LD 0 (IO 0 (BASE 0x3e8)) (ACT Y)))
Instructions can be spread across many lines, and include comments if required.


The file conceptually has three sections:
Which is the set of keywords associated with identifying the Plug-and-Play cards. These usually come at the beginning of the configuration file.
Which is the set of keywords used to select a card and write values to its configuration registers.
Tidy up
Which is the set of keywords used to finish the Plug and Play configuration process.

There are also some keywords for debugging purposes.


There are two ways to initialise the configuration mechanism, corresponding to using pnpdump with and without the two optional parameters.
This method assumes the BIOS has already carried out the isolation process, and allocated Card Select Numbers (CSNs) to each card.

The configuration file specifies the number of cards and the readport address, and then isapnp reads the serial identifier from the beginning of the resource data to find out the identity of each card.

A configuration file using this method will start like:

 (READPORT 0x3bb)
 (CSN 2)
Using this method, and PEEK instructions instead of the configuration setting instructions, it is possible to examine the configuration of the Plug-and-Play cards, without upsetting normal system operation. This can be useful for example to check how the BIOS has configured the hardware. (If you want to get really fancy, you could pipe the output through a script to configure the kernel driver(s) to match).

Note that some cards appear to be broken in that they don't follow the requirement in the second paragraph of section 4.5 of the PnP ISA Spec. (They start returning resource data immediately when entering the Config state from the Sleep state, rather than the 9 byte serial identifier). These cards may not be able to use this method.

Due to the difficulty of determining the correct READPORT address to use (which must be the same as the one the BIOS used), this method may be tricky to get working.

isapnp does ISOLATION
With this method, isapnp carries out the isolation process. This will be required for example on those systems without a Plug and Play BIOS, or with a broken BIOS.

The configuration file simply includes the line

which will scan for a suitable readport address and identify all the devices. You may still want to include (IDENTIFY *) however, as it will printout the names of the devices found. Putting a (READPORT xxx) before the (ISOLATE) will prevent the scanning process.

Note that as of the 1.12 release of isapnptools, ISOLATE can now take an optional parameter which determines whether the existing hardware configuration settings are preserved or not. The default is now to preserve the settings.


This is the core of the process. For each card to be configured (not all need to be), it is first selected using the CONFIGURE keyword. (Cards can be selected using the CSN keyword, but the CSN numbers will change when Plug and Play cards are added and removed, which could result in configuration register settings going to the wrong card).

After this, each logical device on the card is selected in turn using the LD keyword. The registers for that device are programmed using the IO, INT, DMA, MEM keywords and their subwords. Finally the logical device is enabled using the ACT keyword.

For debugging purposes, or to access non-standard configuration registers or vendor specific registers, the REG keyword may be used to directly access the configuration registers by address.

A couple of examples of this part of the configuration file look like this:

  # Card 1: (serial identifier 13 0e 1e 37 b4 19 01 89 14)
  # EDI0119 Serial No 236861364 [checksum 13]
  # Version 1.0, Vendor version 1.0
  # Logical device id EDI0119
  #     Device support I/O range check register
  (CONFIGURE EDI0119/236861364 (LD 0
  #     Compatible device id PNP80d6
  #     Logical device decodes 10 bit IO address lines
  #         Minimum IO base address 0x0240
  #         Maximum IO base address 0x03e0
  #         IO base alignment 32 bytes
  #         Number of IO addresses required: 32
  (IO 0 (BASE 0x0340))
  #     IRQ 3, 4, 5, 9, 10, 11, 12 or 15.
  #         High true, edge sensitive interrupt
  (INT 0 (IRQ 10 (MODE +E)))
  #     Memory is non-writeable (ROM)
  #     Memory is non-cacheable
  #     Memory decode supports high address
  #     memory is 8-bit only
  #     memory is shadowable
  #     memory is an expansion ROM
  #     Minimum memory base address 0x0c0000
  #     Maximum memory base address 0x0dc000
  #     Range base alignment mask 0xff4000 bytes
  #     Range length 16384 bytes
  # Choose UPPER = Range, or UPPER = Upper limit to suit hardware
  # (MEM 0 (BASE 0x0c0000) (MODE bu) (UPPER 0x0c4000))
  # (MEM 0 (BASE 0x0c0000) (MODE br) (UPPER 0x004000))
  (ACT Y)))
  # End tag... Checksum 0x00 (OK)
  (CONFIGURE DFX0000/1493 (LD 0 (IO 0 (SIZE 8)(BASE 0x3e8)) (INT 0 (IRQ 11 (MODE +E))) (NAME "DFX0000/1493[0] --- Modem and Fax") (ACT Y)))


This is just the keyword WAITFORKEY, which returns the Plug and Play configuration mechanism to the Wait for Key state.

The configuration file thus ends with



The following is a complete list of the keywords, showing the heirarchy of validity.


In alphabetical order. The ... in the parentheses implies that the instruction is merely a selector of some sort, and further instructions are required to do something useful.
(ACT arg)
Context: within (LD ...).

arg can be Y or N. Y will cause the logical device to be activated and respond to accesses. N will cause the logical device to be deactivated and isolated from the bus.

If a NAME has been specified, and VERBOSITY is greater than 1, a status message will be output to stdout, summarising the device configuration settings.

(BASE arg)
Context: within (IO ...) or (MEM ...).

arg specifies the base address of the region. Prefix a hex address with 0x.

Context: within (DMA ...).

arg specifies the DMA channel to use. Valid settings are 0..7. Channel 4 means no DMA used. Channels 0..3 are for 8 bit DMA, Channels 5..7 are for 16 bit DMA.

Context: within (IO ...).

Carry out an IO range check to ensure no bus contention with any other device. Only valid if the device supports it, and the device is not already activated.

(CONFIGURE arg ...)
Context: Global.

arg specifies the card Vendor Id and serial number in the form [A-Z][A-Z][A-Z][0-9A-F][0-9A-F][0-9A-F][0-9A-F]/[-#]?[1-9][0-9]*. For example "DFX0000/1493". The serial number -1 implies that the device does not have a serial number; in this case, only one card can of this type can be supported in the system. Some cards appear to include an underscore character as one of the initial three letters of the Vendor ID, this is outside the specification, though supported.

To allow the same configuration files on multiple machines, two additional features have been added from release 1.12:

If the specified device is not found, the device is skipped. Rather than the script aborting.

The serial number of the device may be specified as #n, meaning the nth device found with the given Vendor Id, independent of its actual serial number. Each card must still have a unique serial number to be separately identified.

Context: Global.

This keyword is used to select whether resource conflicts for each of DMA, MEM, IO or IRQ are a Warning or Fatal. Resource conflicts will cause a message to be output, but if the resource is set as Fatal on conflict, the program will immediately abort.

The default is equivalent to

(CSN arg ...)
Context: Global.

arg specifies the Card Select Number of the card to select for access. isapnp assumes you know what you are doing if you use this instruction, and will assume the card exists (and all the cards with lower CSNs). arg must be in the range 1..32, this is a compiled in limit.

Context: Global.

This turns on debugging immediately. Diagnostic messages will be produced as soon as this instruction is read in.

(DMA arg ...)
Context: within (LD ...).

arg specifies the DMA register to configure, in the range 0..1. Each logical device can use up to 2 DMA channels.

Note there is another DMA described in CONFLICT.

Context: Global.

arg specifies the Card Select Number of the card to identify. Identification consists of reading the card's resource data, updating internal tables so that CONFIGURE can find the card, and printing the results (the format of the results can be changed using IDENTIFY-FORMAT). arg must be in the range of valid CSNs (ie number of boards found), or can be specified as * to operate on each card in turn.

Note:VERBOSITY must be greater than 2 to see the results on stdout.

Context: Global.

arg specifies the format string to be used by IDENTIFY when outputting the data for each card, it must be a string enclosed in double quotes. The IDENTIFY-FORMAT command must precede IDENTIFY if it going to have any effect.

The default format string is:

"Board %b has Identity %8 %7 %6 %5 %4 %3 %2 %1 %0: %v Serial No %s [checksum %8]\n"

The following format escapes are recognised:

%b - Card Select (board) Number [Decimal number]

%s - Board serial number [Decimal number]

%v - Board vendor Id [7 character string]

%x - where x is 0..8 - Identification byte x, 8 is the checksum [2 Hex digits]

Context: Global.

Normally, cards which have a CRC error during the reading of the serial identifier in the isolation process are not counted, and the READPORT is assumed bad. Setting this flag means they will be treated as good, and you have to hope that IDENTIFY will fix the identifier. This must therefore come before ISOLATE if it is to have any effect.

(INT arg ...)
Context: within (LD ...).

arg specifies the INT register set to configure, in the range 0..1. Each logical device can use up to two interrupt lines.

(IO arg ...)
Context: within (LD ...).

arg specifies the IO register set to configure, in the range 0..7. Each logical device can use up to eight IO regions. The size of the IO region should be specified using the SIZE keyword. The size of the IO region can be found by examining the output of pnpdump.

Note there is another IO described in CONFLICT.

(IRQ arg ...)
Context: within (INT ...).

arg specifies the interrupt line to use for the interrupt, in the range 0..15. No interrupt is specified using 0. To use interrupts a value in the range 1..15 must be specified. Note that not all interrupt lines are connected, so the resource data must be consulted to get a list of valid settings.

Note there is another IRQ described in CONFLICT.

Context: Global.

This carries out the full isolation protocol. First it resets all the Card Serial Numbers, then isolates them one by one, allocating each one a Card Select Number. If a READPORT hasn't already been specified, it will also search for a valid readport address.

The optional arg may be PRESERVE, the default, in which case the existing configuration settings are preserved, or it may be CLEAR, in which case all the Plug and Play devices are reset to their power-on default configurations.

(LD arg ...)
Context: within (CONFIGURE ...) or (CSN ...).

arg specifies the logical device to configure, in the range 0..n, where n is one less than the number of logical devices on the card. After setting the register to select the logical device, it is read back and checked; an error is generated if there is a mismatch. This behaviour can be changed using the global command VERIFYLD. The number of logical devices on a card can be found by examining the output of pnpdump.

(MEM arg ...)
Context: within (LD ...).

arg specifies the memory register set to configure, in the range 0..3. The memory register sets are the normal range (24 bit addresses). Each logical device can support up to 4 memory regions. There is no direct support for the 32 bit memory descriptors, though POKE could be used if required.

Note there is another MEM described in CONFLICT.

(MODE arg)
Context: within (IRQ ...) or (MEM ...).

Within IRQ, arg specifies the interrupt line polarity and sensitivity using two characters [+-][EL] for [positive|negative][Edge|Level] sensitivity. In most ISA situations this will be +E.

Within MEM, arg specifies memory width and the meaning of the value written to the UPPER register. arg is of the form [BW][RU] for [Byte|Word][Range|Upper]. Note that often these values cannot be set, but they are checked with the hardware value and an error is generated if they don't match.

(NAME arg)
Context: within (LD ...).

arg specifies the name of the logical device to be output when the device is ACTivated. The arg is a string in double quotes.

Context: within most register access keywords.

This instruction causes the register value to be read and a suitable message output to stdout. VERBOSITY must be greater than 0 to see the output.

(POKE arg)
Context: within (REG ...).

arg specifies the value to write to the selected register in the range 0..255.

Context: Global.

arg specifies the address of the readport register to use in the range 0x203..0x3ff. The address chosen must be unused by any other hardware. The bottom two bits are set to ensure the port is on the correct address boundary. This should be the first instruction if used (except perhaps for DEBUG).

The Plug and Play specification specifies three registers. Two of them are write only, at images of the printer status port (so were previously read only), at addresses 0x279 and 0xA79. However, the protocol requires a single readable register. The location of this register cannot be standardised due to the impossibility of finding a single unused address which is common to all systems.

For this reason the address of the readable register is specified in one of the configuration registers, and an algorithm specified to find a suitable non-conflicting location. If you know a good value to use, it can be specified with this command to prevent having to try to discover it.

(REG arg ...)
Context: within (LD ...).

arg specifies the address of the register to configure, in the range 0..255. This may be used to access the various reserved and vendor defined registers on a logical device.

(SIZE arg)
Context: within (IO ...).

arg specifies the size of the region in bytes. Prefix a hex size with 0x. This keyword does not affect any PnP configuration registers, it is simply information for resource conflict checking. If the SIZE is unspecified, 8 will be assumed.

(UPPER arg)
Context: within (MEM ...).

arg specifies the memory range the device can use. The value is either an upper address, or a range (offset) value, depending on the device. Consult the resource data as dumped by pnpdump to find out what the device supports.

Context: Global.

arg is a number from 0 to 3, which represents the amount of status output the program should provide. 0 is mininum, 3 is maximum. The default is 3 for backwards compatibility.

Context: Global.

Normally, isapnp attempts to verify the logical device exists by reading back the the value in the logical device register after setting it. The standard seems rather vague on whether this is a requirement, and it would appear that some hardware fails to read back correctly, so this instruction allows the verification to be turned on and off.

Within VERIFYLD, arg may be [Y|N] to turn verification on and off respectively. If no parameter is supplied, verification will be turned on.

Context: Global.

Returns all cards to the Wait for Key state, as required by the specification.


Check for latest information and FAQ. If you think you have found a problem not mentioned in the latest version, please send a report to


isapnp.conf has been written by Peter Fox <>, the creator and maintainer of isapnptools.


The latest version of the sources may be obtained by ftp from

Or follow one of the pointers to various ftp sites carrying isapnptools from my web page at


Plug and Play ISA Specification, Version 1.0a, May 5, 1994. Available from


pnpdump(8), isapnp(8)