System for configuring an input/output board in a computer
Contents
1. An apparatus for configuring an input output board in a computer as described in claim 1 and further comprising a means for storing said address 4 An apparatus for configuring an input output board in a computer as described in claim 3 wherein said means for storing said address comprises an Appli cation Specific Integrated Circuit ASIC 5 An apparatus for configuring an input output board in a computer as described in claim 4 wherein said computer has a memory means and wherein said means for storing said address further comprises said memory means 6 An apparatus for configuring an input output board in a computer as described in claim 5 wherein said memory means comprises a hard disk b2. back on the computer 14 The invention software will appoint the parameter and configure or reconfigure the I O board In contrast many devices of the prior art required more action on the user s part For example to reconfigure an I O board it often was necessary to power down the com puter remove the cover on the system adjust the switches and or change jumpers which sometimes re quired removal of the board plug the board back into the system replace the cover restore power to the system and reboot the computer Obviously this was very time consuming and was prone to confusion and errors as users often found it difficult to match the hard ware setups configured by the jumpers or the switches to the parameters set in the configuration file on the hard drive To understand the various routines of the invention a review of the technique in the context of the installation mode is representative Referring to FIG 1 a flow chart of one possible installation sequence it can be seen that the present invention greatly simplifies this process from the user s perspective by accomplishing the key steps through software routines As FIG 1 shows the installation mode begins with the step of initiating the routine This can be done automatically or by user action When done automatically it is of course accom plished after the initiating operation of the computer 14 in the traditional manner Once initiated the inven tion acts
3. order to tristate them For efficiency the global sequence is a sequence which starts with the address read from base address with an offset of three Thus in operation the second read sequence routine performs two reads from base address with base offset of three For further effi ciency the global sequence and the unique activation sequence differ by only one value in the read sequence The specific orders of the two are only one different This simplifies circuitry required as one skilled in the art would readily recognize so that instead of having two separate state machines totally independent of each other the board may have one state machine with just two different options at a particular state In addition a board specific deactivation command can of course be provided if desired It should be understood that the process of activating an individual I O board does not involve either a re sponse from the board or the creation or change of any information on the board First avoiding any need for a response allows the state machine to monitor for the proper sequence without the I O board being activated Second the aspect of avoiding any creation or change 5 367 640 7 of information that is being substantially non destruc tive serves to avoid inappropriate responses within the system as discussed later in the context of the step of assessing if the chosen address is unique Either before activating aspects of one I O boa
4. these solutions are discussed herein Perhaps the most common solution and that referred to above is to provide physically changeable circuitry on the I O board itself The address or other character istic is thus personalized by switches or jumpers which the installer must know how to set The main drawback is that manual intervention is required at installation time which may lead to configuration errors This can also require more detailed customer documentation and as a practical matter often leads the user to enlist professional help A second solution in the prior art is to replace the I O bus Recently I O busses have been developed which can specifically select one of the slots available through a slot select line or other technique Naturally this has the undesirable consequence of increasing cost and possibly even making slot location an important installa tion criteria As an example of such a solution U S Pat No 4 755 934 to Inoue discloses a system which selects a board location by a slot select signal generated through the I O bus and then assigns the board in that 5 20 25 35 40 45 55 60 65 2 slot a specific address While such a solution can over come the need for installation decisions it does not meet the criteria of the present invention of accommodating existing designs Another solution is that proposed in U S Pat No 4 964 038 to Louis This proposes a system in which all I O b
5. 0 is in part configured by interruptable wiring 13 By merely interrupting one or more of the traces comprising wir ing 13 the user can physically change the sequence recognized This in turn changes the activation combi nation recognized Thus in the event a user desires to have two identical boards it can also be accomplished by the present invention Two traces are shown in FIG 2 by providing four traces sixteen combinations are 20 25 40 45 50 35 60 65 10 possible This would allow sixteen possible I O read sequences in a computer system for the same type of board Once the software now knows which board the user wants to configure it is likewise possible to select unique direct memory access or DMA channels and interrupt or IRQ channels In addition and inciden tally highlighting how features may or may not be com bined and still fall within the present invention the preferred embodiment does not use the full three level conflict check to assign these parameters Instead such are merely chosen from a prioritized table without a full conflict check since it is far less likely that a conflict will exist at this stage In addition manual selection is possi ble Once again the manual selection does the same thing for DMAs and IRQs as it did for base address As for the DMA channel parameters it is conflict checked only in the event a particular I O board type is in volved Recall that the type of
6. I O board was deter mined by the computer 14 as part of the initial address conflict check This information can then be used to trigger conflict checks only for particular board types further highlighting the flexibility of the present inven tion For the specific assignment of a compression DMA channel when a compression card is involved the routine merely checks for a conflict by using the channel A small block of data is sent to the I O board is passed through one of the chips on the board put back on the hard drive and compared to what was sent If it is identical uniqueness is assumed Again this is a specific routine which is presented only to highlight the flexibility offered by the present invention Naturally other such specific testing can be accomplished and still fall within the scope and spirit of the present invention As mentioned earlier avoiding inappropriate re sponses during the attempts to arrive at a unique address is an advantage of the present invention This is not only accomplished by using substantially non destructive commands and rebooting the system when appropriate but it is also accomplished by only activating certain aspects of the I O board Initially the present invention is configured to start out in a default condition having all important connections the specific connections es tablished by the board slot in the electrically discon nected or tristated condition The necessary lines must be unt
7. United States Patent m9 Hamilton et al 54 75 73 21 22 63 51 52 58 56 SYSTEM FOR CONFIGURING AN INPUT OUTPUT BOARD IN A COMPUTER Inventors Bradley W Hamilton John W Slattery Kerry J Monroe all of Fort Collins Colo Assignee Hewlett Packard Company Palo Alto Calif Notice The portion of the term of this patent subsequent to Dec 28 2010 has been disclaimed Appl No 96 196 Filed Jul 22 1993 Related U S Application Data Continuation of Ser No 932 919 Aug 20 1992 aban doned which is a continuation of Ser No 693 358 Apr 30 1991 abandoned Tit dasse G06F 15 08 G06F 9 00 G06F 13 00 MS o oss EAE E 395 275 395 800 364 284 2 364 238 3 364 280 2 364 DIG 1 Field of Search 395 275 325 800 425 370 17 93 340 825 07 825 52 364 490 514 371 11 1 References Cited U S PATENT DOCUMENTS Re 33 705 10 1991 Caprio etal os cescesscsseseees 364 900 4 268 901 5 1981 Subrizi et al oe 364 200 4 373 181 2 1983 Chisholm et al 2 0 364 200 4 556 953 12 1985 Caprio etal sseessesssessesscee 364 900 4 589 063 5 1986 Shah et al wee 364 200 4 660 141 4 1987 Ceccon et al ose 364 200 4 670 855 6 1987 Caprio et al ween 364 900 4 675 813 6 1987 Locke e sessserererersescsesessseses 364 200 4 730 251 3 1988 Aakre et al oe eeeeee 364 200 4 750 136 6 1988 Arpin etal eee 364 514 US005367640A 11 Patent Nu
8. and that any level of checking can be instituted While at present three levels have been found to be adequate as the configurations of systems encountered changes so too may the types or numbers of routines used change In addition the invention also offers an additional degree of protection against inappropriate responses In the event that a conflict is discovered anywhere in the pro cess not only does the routine act to select another address it also triggers the need to reboot the system after finally storing an appropriate address and other information This reboot acts to reset the entire com puter system or at least so much as might reasonably be affected and thus will act to avoid any inappropriately set values in the system Naturally if the address ini tially selected turns out to be unique no such reboot will be necessary Once a unique address has been chosen the setup or installation mode can be exited Again this can be ac complished by executing a standard command in this case a write at the base address with an offset of seven Notice that the board has not yet been operated Rather the unique parameter is saved for later use in the opera tion mode The entire routine can then be repeated to change other addresses other parameters other boards and the like As mentioned earlier there is the possibility of manu ally changing the activation sequence Referring to FIG 2 it can be seen that state machine 1
9. anges in conflicting I O boards by activating components on the board through use of a state machine by using non destructive commands for initial checks by tristating unnecessary lines and by re initializing registers whenever a conflict is encountered Additionally no address space is used to activate the board 6 Claims 3 Drawing Sheets U S Patent PRIORITIZED LIST ASSESS IF UNIQUE Nov 22 1994 Sheet 1 of 3 ACTIVATE 1 0 BOARD SELECT INITIAL PARAMETER LVL 2 UNIQUENESS ASSESSMENT CONDUCT LVL 3 UNIQUENESS ASSESSMENT STORE PARAMETER 5 367 640 U S Patent Nov 22 1994 Sheet 2 of 3 5 367 640 20 N FIG 2 5 367 640 Sheet 3 of 3 Noy 22 1994 U S Patent ns FIG 3 5 367 640 1 SYSTEM FOR CONFIGURING AN INPUT OUTPUT BOARD IN A COMPUTER CROSS REFERENCE TO RELATED APPLICATION This is a continuation of copending application Ser No 07 932 919 filed on Aug 20 1992 which in turn was a continuation of application Ser No 07 693 358 filed on Apr 30 1991 each now abandoned BACKGROUND OF THE INVENTION Generally this invention relates to the field of con trolling input output boards which are connected to an I O bus Specifically the invention focuses on tech niques to configure aspects such as address space of input output boards without needing to physically con nect or change jumpers on the card either at physical installation or after a syste
10. any use of address space during activation and requires a minimum in terms of specific I O board circuitry Once partially activated the technique selects an initial 5 367 640 3 address or other parameter in a fashion which is likely to result in a unique address The routine then assesses if this initial address is unique if not another address is selected If the address is unique the routine assigns the address to that I O board The technique can act to disable electrical connections so as to avoid any inap propriate responses After installation the technique can also act automatically to confirm proper installation each time the I O board is operated Thus it will even overcome address or other conflicts created unwit tingly even after the particular board has been installed correctly An object of the invention is to provide a device which simplifies installation needs Naturally it is an object to avoid any need for the installer to have any specialized knowledge or training in order to accom plish installation Additionally it is an object to mini mize the need for involved installation documentation It is thus an object to achieve assignment of address or other parameters automatically through operation of the computer In assigning such parameters it is an object to accomplish the task efficiently in a manner which prioritizes likely assignments and thus achieves the assignment as quickly as possible An important ob
11. are dis closed throughout the specification and claims BRIEF DESCRIPTION OF THE DRAWINGS FIG 1 is a flow chart diagram of the installation mode of the present invention with a variety of routines included FIG 2 is a schematic representation of the state ma chine portion of an I O board according to the present invention FIG 3 is a schematic representation of one embodi ment of the present invention showing internal elements of the computer DETAILED DESCRIPTION OF THE PREFERRED As can be seen from the drawings the present inven tion is relatively simple in nature and can be easily ac complished by those skilled in the art once its general nature is known Basically the technique uses an initial series of interactions between the computer 14 and the T O board to arrive at the appropriate configuration parameters These interactions can be but need not be accomplished in two modes an installation mode and an operation mode The first mode is installation This is when a periph eral is introduced to the computer system for the first time or when a user is reconfiguring the computer sys tem The second mode is normal operation of the I O device for example a tape drive This can include either a repetition of the interactions accomplished in the installation mode may include a more detailed interac tion than the installation mode or may be a more abbre viated interaction than that of the installation mode Thus
12. automatically to selectively activate an I O board and select an initial value for the I O board the order of these is not important The way in which the present invention individually activates an I O board offers many advantages First it does not require a separate line from the I O bus 15 Second it can be accomplished with relatively inexpen sive circuit additions to the I O board Essentially the activation operation is individualized to a single board by using a specific sequence of common operations The I O board is configured to recognize this unique se quence and then to activate some aspects of the board in response As an additional protection against inap propriate responses only so much of the I O board need be initially activated as is necessary to assess the uniqueness of the assigned parameter As mentioned a specific sequence is used which the I O board can recognize This is recognized by use of circuitry commonly referred to as a state machine 10 as those skilled in the art might readily understand once they are exposed to this unique use even though state machines are traditionally not used for such a routine While any sequence could be used under the concepts of the invention the preferred embodiment uses a read sequence referred to as the first read sequence The first read sequence activates the board to enter a setup mode This unique activation technique also has the advantage of allowing multipl
13. cation the identification code must be consistent with a list of acceptable codes contained in a table If the value read back is not in the software table on the computer 14 in other words if the contents received back from the address locations are not what should be expected from any of the known boards that could possibly reside in the system the routine assumes no board exists or that a possible conflict at that address exists If a conflict is indicated the routine returns to select the next most likely address and tries it Importantly such a technique is effective because in the event two boards respond at once i e both recognize the same address an unintelligible signal is produced This signal will thus be different from the identification code and will thus indicate that the initial address is not unique As an additional note it should be understood that the board identification code not only tells the software which board is being installed but it also tells it how may bytes to read since some boards use 8 bytes and others use 16 bytes etc The identification code can also indicate what hardware version is being installed This allows updates or revision to the board to be recognized by the software where necessary or desired 5 367 640 9 Earlier it was mentioned that the routine used to assess if the chosen address is unique is an escalating routine By this it is meant that the routine next executes commands wh
14. conducting the potentially destructive opera tion of writing to an address space the present inven tion significantly departs from this approach As mentioned state machine circuitry 10 as shown in FIG 2 is configured to react to a sequence specific to that I O board Referring to FIG 2 it can be seen that this circuitry is responsive to computer signals and actually includes one or more programmable array logic unit PAL 11 and counter 12 This is relatively inexpensive Also by placing such circuitry on the I O board itself the invention can meet its goal of being compatible with standard I O busses The actual se quence which state machine 10 recognizes may be set through interruptable wiring 13 State machine 10 has the inherent capability to automatically reset if the complete sequence is not received This means that any read sequence not matched in the read sequence de scribed above will reset state machine 10 If the se quence is followed each successive read in the se quence will move state machine 10 on to the next state If the state machine requires sequences to occur in a specific order any sequence outside the order will reset the state machine In addition state machine 10 is configured with a global sequence referred to as the second read se quence Thus each board may be configured to re spond to two specific sequences one to activate a spe cific board and one to activate all boards in
15. e boards to share ad dresses DMA channels and IRQ channels It thus acts to greatly increase I O board possibilities In order to allow individual activation the sequence needs to be unique It should act as a type of combina tion to unlock the board that other software or func tions will have a very very low probability of perform ing In the preferred embodiment a series of sixteen 20 25 30 35 40 45 50 35 60 65 6 properly chosen I O reads is used because it has been found that such a sequence rarely occurs in normal operation Naturally this number may vary based upon system configurations likely to be encountered At pres ent it is believed that less than four I O reads in the first read sequence would not present a sufficient number to properly serve as the combination lock desired Natu rally the number of reads can be increased as desired In addition to being a series composed of common commands the use of a read sequence in general offers the additional advantage of being substantially non destructive This is discussed later in the context of the step of assessing if the chosen address is unique Also the use of state machine 10 allows individual activa tion to occur without utilizing any address space on I O board 2 This can afford significant advantages not only in cost but also in functionality While the prior art teaches not only utilizing address space for activation but also
16. es additional information Third it uses a repetitive routine Referring to FIG 1 it can be seen how the step of assessing if the initial address is unique is accomplished in a multilevel escalating manner As shown in FIG 1 three levels of assessment are accomplished While nat urally any number is possible the important aspect is that at the end it be well known that the selected ad dress is in fact unique The first level starts by using 10 15 20 25 30 35 40 45 50 55 60 65 8 common commands which are substantially non destructive to avoid destroying any information which could be contained on other I O boards which might recognize the initial address by executing a write com mand or otherwise As with the commands chosen to activate and deactivate the I O board this step may use another such sequence referred to here as a read se quence In choosing such terms to identify the various read sequences involved it should be understood that no order is implied The terms first read sequence second read sequence and read sequence are chosen for differentiation purposes only as the tech niques of the invention can be arranged in and order and still fall within the scope of the invention As mentioned the commands are substantially non destructive This means that they are of such a charac ter as to be very unlikely to change any information contained on the I O boa
17. es presented here or to de scribe and claim all possible revisions to the present invention which may be accomplished To the extent such revisions utilize the essence of the present inven tion each would naturally fall within the breadth of protection encompassed by this patent This is particu larly true for the present invention since its basic con cepts and understandings are fundamental in nature and can be broadly applied not only to a variety of devices but also in a variety of manners We claim 1 An apparatus for configuring an input output board in a computer comprising a a computer having a programmable processor through which commands may be issued an input output board connected to said computer and which responds to said commands so as to create a command response sequence wherein said command is likely to cause a change to said I O board a means for communicating said commands to said I O board a means for assigning an address to said I O board and e a means for assessing if said address is unique to said I O board through operation of said computer to check if said initial address is in use elsewhere wherein said means for assessing utilizes said com mand response sequence and wherein said means for assigning is responsive to said means for asses sing 2 An apparatus for configuring an input output board in a computer as described in claim 1 wherein said command response sequence is repetitive 3
18. g others has not been available prior to the present invention Cer tainly the long felt need existed and as the present in vention shows the implementing arts and elements had been long available Those skilled in the art appear to have been lead to believe that hardware and other such solutions were the only practical possibility by some of the prior efforts In addition the degree to which the common usage preconditions approaches from device command and connection perspectives has taught those skilled in the art in a direction away from that taken by the present inventors Each appear to have taught away from the combination of commercial sensi tivity and technical expertise necessary to achieve the present invention All may have combined to cause the simple fact that those skilled in the art failed to see that the problem could be solved in a relatively simple man ner SUMMARY OF THE INVENTION The present invention discloses a method and appara tus which can accomplish automatic I O board configu ration even when connected to a standard I O bus The technique involves software routines executed by the computer which first acts to activate the I O board then to install the I O board properly and then auto matically acts to confirm such installation as part of the operation of that I O board In use the routine initially activates some aspects of a specific I O board This activation is accomplished in a manner which avoids
19. ich have an even higher probability of discovering a conflict The next level of assessment is to write to the board to tell it to return a value other than the identification value In the preferred embodiment a common com mand is sent to the I O board which resets the same values to return all bits as zeros This creates a com mand response sequence Also the state machine can be expanded to perform this function without any need for a write operation Again for efficiency by using a sin gle operation to reset all such values less steps are in volved As with the read sequence conflict check all values are compared by the computer 14 to assure that two boards do not respond at the same time If a conflict exists again the routine returns to select another ad dress and try it The prior process is repeated for the third level of conflict check with an operation which establishes all bits as one s at the same locations If it indicates that no conflict was discovered a unique address has been chosen In addition the computer 14 has identified that a board is residing at that location and what type of board is residing at that address location All this has occurred without ever communicating with the board in the formal sense and even without ever fully activat ing the board In regard to the prior steps it should be understood that any type of operation or command can be chosen that any number of repetitions can be used
20. in system configuration Not only does the invention minimize any use of potentially destructive actions in achieving its aims but it also acts automati cally to purge any undesirable effects when such be come possible As mentioned an object is to assess if the address or other parameter is unique to the I O board before act ing to assign it to that I O board In so doing it is an object of the invention to use common commands that is commands traditionally available and utilized by most I O boards in assessing such uniqueness In addition it is also an object of the invention to provide only so much operation as necessary to discover a conflict and thus not only achieve its aims efficiently but avoid inappropriate results as much as possible 25 45 50 60 65 4 Yet another object of the invention is to accommo date user input when necessary or desired The inven tion not only allows the user to override the automatic parameter selection process but it also allows the user to change the configuration of the I O board itself if desired Finally it is also an object of the invention to provide configurations which allow a variety of I O boards to remain in use even though such boards utilize the same address In so providing the invention greatly expands the number of possibilities for numerous peripheral devices while still accommodating a standard I O bus structure Naturally further objects of the invention
21. ject of the present invention is to minimize any hardware required on the I O board itself in order to achieve the objects herein stated Accord ingly the present invention has the object of utilizing computer capabilities with minimal added board capa bilities in order to accomplish its functions An object is thus to avoid use of address space to configure the board during activation on the I O board and to effi ciently store the address once assigned on the board in existing components Generally an object is thus to use existing features of most I O boards to the extent possi ble Another object of the present invention is to provide both the method and a device which integrates with existing designs of computers Accordingly it is an object to achieve the functions desired while allowing use of a standard I O bus In addition it is an object to allow utilization of the invention with existing I O boards if desired In so doing an object is to not only achieve proper configuration upon installation but also to strategically check the installation at various times to confirm that no configuration changes or additions of I O devices have occurred that might have created a conflict Additionally it is an object that if such a con flict is created for the invention to automatically recog nize such a conflict Yet another object of the invention is to provide a technique which avoids undesirable effects in the event of a change
22. m change Assembling computer systems to suit individual needs or desires by adding peripheral devices is often done When such devices are connected frequently they connect to the computer through an I O card These I O boards are installed at initial computer manu facture as well as whenever a user adds new capabilities to the computer by plugging them into available slots on the input output bus of the computer Unfortu nately the process of adding capability involves more than just plugging in the I O board and running the computer The user or installer must configure the I O board so that the computer can recognize it to commu nicate with it This can be an involved process When a standard I O bus the type of I O bus traditionally installed in most computers is involved this process can be quite involved For a computer to be able to communicate with the T O board the computer must not only know what type of board it is it must be able to selectively locate the I O board and direct communications only to it This is referred to as addressing the I O board As an example of the difficulties potentially encountered when assem bling or changing such computer systems the address must be assigned so that no other I O boards have that same address This problem of address allocation has been known for many years several different solutions have been proposed all with limitations overcome by the present invention Several of
23. mber 5 367 640 45 Date of Patent Nov 22 1994 4 755 934 7 1988 Inoue enire 364 200 4 825 404 4 1989 Theus 0 cccccesssesneneeeees 364 900 4 849 931 7 1989 Ishii et ab oe eesesseseeees 364 900 4 910 655 3 1990 Ashkin et al oceans 364 200 4 918 598 4 1990 Ashkin et al ose 364 200 4 964 038 10 1990 Louis et al 364 200 4 992 976 2 1991 Yonekura et al 364 900 5 014 193 5 1991 Garner et al woe eeesees 364 200 5 031 115 7 1991 Hayashi eseecseeteeceee 364 519 5 034 878 7 1991 Haapala et al eee 364 200 5 038 320 8 1991 Heath et al 364 900 5 111 423 5 1992 Kopec Jr et al 395 500 5 161 102 11 1992 Griffin et al 395 800 5 257 387 10 1993 Richek et al eeens 395 800 OTHER PUBLICATIONS Rampage Q Plus 286 User s Manual AST Research Inc Jun 1988 p ix Primary Examiner Gopal C Ray 57 ABSTRACT An automatically configurable I O board and associ ated software avoids any need for jumpers switches or other configuration changes upon installation of the board Utilization of the main computer capability to select addresses and values likely to be available in volves an installation or other routine which arrives at a unique parameter through common commands and repetitive execution Uniqueness of the parameter or address is accomplished by checking for use elsewhere in the system prior to operation of the board Steps are taken to avoid any inappropriate ch
24. oards connected to the I O bus utilize specific circuitry capable of generating a random address If there are as many addresses generated as there are boards connected it can then be assumed that each board has a unique address if not the random genera tion process is repeated While this solution does specifi cally address the ability to be compatible with standard I O busses it has drawbacks overcome by the present invention Among these are both the requirement that all boards to be of that type again not allowing accom modation of existing systems and the inherent difficul ties of using randomly generated addresses in configura tions which usually place some constraints on address possibilities One other solution is that proposed by U S Pat No 4 675 813 to Locke in which the I O board includes circuitry which specifically recognizes a hardwire set address and a configurable address register While this solution can work with a standard I O bus and with other traditional I O boards it has other limitations It does require the hardwire set address to be unique This can be unacceptable in the present environment in which a manufacturer simply cannot know how each system might be configured In addition it also is lim ited in that only one such I O board can be placed in any system Again the present invention overcomes such limits While each of the above limitations have been recog nized a solution to such problems amon
25. once all possible details are understood each may be combined as desired to achieve the goals of the in vention This would be evident to one skilled in the art and is disclosed to some extent in the claims although they do not set out all the possible combinations Naturally to need the invention an I O board or some type of interactive circuitry which may or may not be separately attached to the computer 14 must be connected to the computer system In most computer systems this is usually done by connecting the I O board into a board slot within the computer case This board slot is actually a connection to the I O bus 15 of the computer 14 It establishes a number of specific connections 1 between the computer 14 and the I O board The I O bus 15 serves together with its numer ous electrical connections 20 as a means for communi cating between the I O board and the computer 14 If the I O bus 15 is a standard bus it will not have the inherent capability to select each slot individually Thus for the present invention the I O board may be randomly connected to any slot of the I O bus 15 it is 5 367 640 5 not dependent on location Once physically installed the methods of the present invention can then be ini tialed automatically or by the user by activating the installation mode of the invention when desired prior to running that I O board Thus the user need only plug the board in and put the cover
26. rd or immediately afterward as shown in FIG 1 the tech nique selects an initial parameter value Again as ac complished in the preferred embodiment the base ad dress parameter is selected Rather then merely ran domly trying a base address as shown by the prior art the invention utilizes a prioritized list This list is actu ally generated and stored on the computer 14 prior to these steps Thus the memory means 17 of the com puter 14 serves as part of the means for assigning the address 16 or other parameter which is on the com puter 14 rather than added to the I O board The prioritized list is designed to start with the most likely address to be available initialiy It is prioritized based on widely disseminated industry specifications which spec ify what addresses some peripheral devices use Natu rally this order may change from time to time as addi tional information becomes available In addition user override is possible This would best be accomplished without accessing the board itself so keyboard input is accommodated in the preferred embodiment At present the list includes only seven possible base addresses This minimizes the hardware required on the I O board Naturally additional base address possibili ties can be included if desired In order to accommodate operational needs well understood to those in the art in an efficient manner each of these base addresses is chosen not only for its probabili
27. rd or within the computer 14 Certainly a write command acts to replace infor mation contained at the write location As such it is a destructive operation While a read sequence can change information this is far less likely thus it is a substantially non destructive operation In the context of activating the board as discussed earlier this is signif icant as if a command which is destructive is used any unsuccessful attempts at assigning an address would destroy potentially important information Unlike the first read sequence the read sequence does not rely on order to the same extent Instead it is merely a true read sequence which ascertains the information contained in each address location Again for effi ciency an I O board according to the present invention may be configured but need not be so configured so as to have an identification code in such address location Thus the read sequence also discovers useful informa tion in the event the address is found to be unique The conflict check through this sequence is accom plished by reading each address location used by the particular I O board It can do this sequentially It is thus repetitive not in the sense that it does the same thing over and over but rather in the sense that it does a different operation to see if the board correctly re sponds to each operation In the case of the read se quence not only must an identical identification code be returned at each lo
28. ristated so that they can be used This includes any combination of data lines which are connected to the address space DMA lines IRQ lines and the like This is easily accomplished through use of a control register as those skilled in the art will readily recognize Other techniques are of course possible While such registers are used to tristate some of the specific connec tions of the board their use is not normally associated with an automatic configuration routine as disclosed here By tying the control register to the state machine it can only be utilized after a unique address has been assigned This fact and the fact that the configuration of the board has a default tristate condition further affords the advantage of avoiding any inappropriate responses by preventing electrical activation of the lines before their time Thus the I O board itself can con tain the means for tristating such lines Once a unique parameter is found it may be stored preferably on existing nonvolatile memory of the com puter system such as the hard disk 18 While a nonvol atile storage means can be added to the I O board as in some prior art devices the present invention uses exist ing nonvolatile memory on the computer 14 for effi 11 ciency purposes This also saves cost The unique value can then be used in the second mode the operational mode _ The operational mode of the present invention can be nearly identical to the ins
29. tallation mode can include less than the installation mode or can include more than the installation mode depending on circumstances or desires While at first glance it may appear unnecessary to re do each of the steps this cannot be known with adequate certainty since changes in system configura tion can be frequent and since the invention is designed to be compatible with other traditional I O boards Thus prior to actually initiating operation of the I O board the step of confirming parameter uniqueness can be accomplished Naturally this can and should use the information obtained during the installation mode for efficiency In the preferred embodiment most of the steps are identical with only minor exceptions Importantly the initial address or other parameter selected to be tried should be the value originally arrived at through the installation mode This is relatively straightforward As to the level one conflict check namely accom plishing the read sequence it is already known that a board exists and what type of board so the routine will perform the read sequence for that one board In the operational mode the unique parameter is also assigned to the board While as mentioned before this is in volatile memory the two part procedure used in the preferred embodiment overcomes and even takes advantage of this limitation In addition the invention expands upon how the prior art stored such information by using not onl
30. ty of being otherwise unused but also so that most have at least sixteen con tiguous bytes free In operation the computer 14 acts to select the most likely base address to be available as an initial address This initial address is then assessed to see if it is unique to that I O board If it is not unique the next on the list is tried and so on Once an initial parameter value such as a base ad dress is chosen the technique automatically acts to assess if that value is unique to the I O board By doing this through operation of the computer 14 the com puter serves as a means for assessing uniqueness in con trast to the prior art Again by using the computer s 14 programmable processing capability 21 cost is saved Certainly the use of a priority list developed with the intent that the first value be unique is an advantage over the prior art which merely uses random generation of an initial value In some instances this may be enough however in order to accommodate the broad variation in system configurations this initial choice needs to be checked As alluded to in the prior art this can be accomplished through a unique routine how ever the present invention accomplishes this through the use of common commands in several unique man ners First it allows for a multileveled escalating assess ment routine Second it accomplishes initial assessment in a fashion which is substantially non destructive and which provid
31. y the board register but by using the Application Specific Integrated Circuit ASIC 19 on the board By so doing the invention achieves such storage while potentially reducing costs Finally after all operation of the board for the pres ent session is done such lines may be tristated If done at this point it allows sharing of the same base address DMA channels and or IRQ channels This can be easily accomplished through the control register as mentioned earlier As will be readily understood by those skilled in the art the foregoing methods may be accomplished with 5 367 640 5 10 20 25 30 35 only minor changes to traditional I O boards With 45 reference to the claims it should be understood that the various steps can be accomplished by means which may already exist on the computer 14 on traditional boards This is in keeping with the goal of requiring the mini mum amount of change to the hardware of the I O board as possible The foregoing discussion and the claims which fol low describe the preferred embodiments of the present invention Particularly with respect to the claims it should be understood that changes may be made with 50 55 65 12 out departing from the essence of the invention In this regard such changes will naturally fall within the scope of the present invention It is simply not practical to describe and claim all possible permutations and combi nations of the new routin
Download Pdf Manuals
Related Search