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1. TEP SPECHNICA CO LTD Sikenica CUnet Introduction Guide A Guide to the CUnet Protocol Note 1 The information in this document is subject to change without prior notice Before using this product please confirm that this is the latest version of this document 2 Technical information in this document such as explanations and circuit examples are refer ences for this product When actually using this product always fully evaluate the entire sys tem according to the design purpose based on considerations of peripheral circuits and the PC board environment We assume no responsibility for any incompatibility between this product and your system 3 We assume no responsibility whatsoever for any losses or damages arising from the use of the information products and circuits in this document or for infringement of patents and any other rights of a third party 4 When using this product and the information and circuits in this document we do not guaran tee the right to use any property rights intellectual property rights and any other rights of a third party 5 This product is not designed for use in critical applications such as life support systems Con tact us when considering such application 6 No part of this document may be copied or reproduced in any form or by any means without prior written permission from StepTechnica Co Ltd TEP SPECHNICA CO LTD Introduction2. Standard unit of time 2 Standard unit of time sharing 3 Cycle configuration 4 Cycle time 5 Partitioning and owning of memory 6 Data sharing by copying data in memory block 7 Practical side of mail sending reception 8 Control of mail sending reception 9 Time required to send receive mail 4 1 Standard Unit of Time The standard unit of time in the CUnet protocol is TBPS In the CUnet protocol a signal consists of two values with a given time of Hi and Low of RZ Return to Zero or Manchester Code that function in pairs Fig 4 1 In the CUnet protocol the baud rate refers to the BPS Bit Per Second unit RZ 1 RZ 1 RZ 0 RZ 0 RZ 1 representing how many times of the small est unit one Hi level or one Lo level mak ing up one pair occur in 1 second TBPS 8 Up P Passage of time means the time width of one pulse For Teps Teps example if the baud rate is 10 Mbps the time TBPS is 100 ns indicating that 10 000 000 Hi level and Lo level pulse signal strings propagate over the network in 1 second Keyword TBPS Standard unit of time Baud rate BPS Bit Per Second Fig 4 1 RZ Return to Zero TBPS TEP SPECHNICA CO LTD Introduction Guide 4 2 Standard Unit of Time sharing The CUnet protocol defines the standard unit of time sharing as a frame and a required time of one frame as Frame Time The CUnet protocol also defines two types of positive
3. the status of GM linked by the latest cycle The flag also assures that MB data of the self station is copied correctly to the station corresponding to the status Pe ee SFE TECHNICA Co LTD CUnet 6 2 4 Status in Practical User System In the CUnet once a stable environment is provided link is unestablished is unlikely A link is unestablished when a packet that the CUnet IC received is discarded according to the test s due to an external noise or improper environment This unestablished link is also described as link is bro ken If the link is broken the status flag that the user system references will show either both of the receive and link status flag bits as OFF refer to the second cycle of SA xx side in Fig 6 or the receive status flag bit as ON and but the link status flag bit as OFF refer to the third cycle of SA yy side in Fig 6 These show the link is unestablished Keyword Link is unestablished Link is broken 6 2 5 Recovery In common and popular communications when a packet is prevented from being sent received due to exter nal noise or an improper environment the packet can be recovered using a retry In this case a retry is necessary because if a packet is lost communication itself is lost In contrast the CUnet protocol has no retry concept reforwarding because it uses a cyclic time sharing operation that allows communications to be performed continuously an
4. 4 all the CUnet ICs connected via the network should synchronized The CUnet protocol defines four phases START phase CALL phase RUN phase BREAK phase to start the station enter into network leave network and maintain cycle synchronization These four phases assure discipline and synchronization of multiple CUnet ICs connected via the network This section describes discipline that maintains synchronization in each phase Figure 5 shows the phase transition 3 Cycle times START phase Cycle of Final SA lt Self SA detected Cycle of Final SA2 Self SA or station detected in CALL o phase Cycle not detected Resizing of Final SA gt Cy CALL phase Self SA detected New entry of station RUN phase L Fig 5 Phase Transition in CUnet Keyword START phase CALL phase RUN phase BREAK phase 5 1 START phase The CUnet protocol only receives for about three cycles right after startup in order to recognize the operat ing status of the CUnet protocol This period is called START phase If the CUnet protocol cannot confirm reception of a packet from other stations during the START phase the entire network recognizes it as a new startup to transit to the CALL phase If the CUnet protocol can con firm reception of a packet from other stations during the START phase the network transits to the RUN phase SFE TECHNICA Co LTD CUnet 5 2 CALL phase The CALL phase means the stage in which the
5. CUnet is waiting to be connected During the CALL phase any station repeatedly sends call packets an interval of two to three cycles so that the station in the START or CALL phase can be recognized The CALL phase transits to the RUN phase after the self station recog nize the reception of the call packet from other stations 5 3 RUN phase The RUN phase means the stage in which the CUnet operates normally The RUN phase continues until when any station cannot receive all the packets from other stations or when the user system instructs the net work to stop 5 4 BREAK phase The BREAK phase is an exception state for the CUnet During the START phase when other stations are already in the RUN phase and the SA with values greater than those of the Final Station FS that defines a cycle is set the START phase transits to the BREAK phase because the station cannot enter the cycle The station in the BREAK phase sends a break packet at the timing of public frames in order to prevent interference with the RUN phase to demonstrate to other stations that there is a station in the BREAK phase The BREAK phase transits to the RUN phase when Final Station gt Station Address 5 5 Calibration of time The CUnet protocol defines calibration of the cycle timing of all the CUnet ICs connected via the network with reference to the source Station Address attached to a packet received in the following four cases This calibration allows cycle synchroniz
6. Time Required to Send Receive Mail In the CUnet protocol the time required to send receive mail is calculated from the following equation 3 However the following three items are not included so the time obtained from the equation 3 should only be used as a guide when building a user system 1 Wait time for obtaining use rights for public frames when stations exceeding the public frame counts start to send mail simultaneously 2 Retry time due to 5 in 4 8 Management of Mail Sending Reception in case when the packet to be sent at the timing of public frames is discarded based on a test described later in 6 1 Test at Packet Reception because the packet is damaged by external noise or improper environment 3 Wait time that station must wait for until the already mail is terminated when it starts to send mail between other station that is already sending receiving mail Equation 3 Byte count of dataset 7 8 3 x cycle time sec In a partial solution underlined part digits after the decimal point are dropped Reference S Mbps the time required for sending receiving of 250 bytes of mail can be calculated as fol For example in a system FS 3 that is operated by four stations with a baud rate of 12 lows 250 7 8 3 x 109 us 35 x 109 us 3 82 ms TEP STECHNICA Co LTD Introduction Guide 5 Synchronization of CUnet IC To implement cyclic time sharing described in section
7. half duplex communication mode allowing sending and receiving of serial communication signals between CUnet ICs is used CUnet can be used with many types of network cables and differential driver receiver components TRX comprising net works For practicality and economic efficiency StepTechnica recommends the following network 1 Network cables Cables equivalent to or better than LAN cables 10BASE T Category 3 or higher and shielded network cable Use one pair of conductors leave the rest open 2 TRX driver receiver components Differential driver receiver based on RS 485 components and pulse transfer for electrical isolation 3 Baud rate Select from 12 6 and 3 Mbps These baud rates are usually selected depending on the network length network cable length Table 1 Each connection point of a multi drop network Table 1 Baud Rates and Network Cable Lengths cable is called a branch Table 1 indicates the network cable length for the CUnet when using the Baud rate Network cable length network with 32 or less branches to 100m The recommended differential driver receiver is an to 200 m RS 485 based driver receiver Therefore the branch count 32 stipulated in the RS 485 specifi to 300 m cation is used as a guide in Table 1 Up to 64 CUnet stations can be connected to the CUnet enabling connection of 64 branches This recom mended network is isolated electrically by a pulse transform
8. station at SA 0 owns the area at MB 0 of GM or the owned area of the station at SA 0 is GM area of MB 0 Fig 4 5 Partitioning and Owning of Memory Global Memory GM Memory Block MB Owning Owned area TEP STECHNICA Co LTD CUnet 4 6 Data Sharing by Copying Data in Memory Block The CUnet IC where the station address corresponding to the ST is set packetizes the value of SA and the owned Memory Block data of Global Memory GM to send it a packet to the network After the CUnet IC receives the data packet it writes the received data to the MB of the GM of its self station indicated by the SA value in the packet This allows data in the MB to be copied from one CUnet IC to all the CUnet ICs connected via the network The ST proceeds each time the frame goes by and thus data in the MB owned by each SA is copied between all the stations When one cycle is completed copying of data between all the stations is also completed allowing each station connected via the network to share the mem ory data From Figure 4 6 when ST 0 data at MB 0 of GM is transmitted from the station at SA 0 to the network After the CUnet IC receives the data the CUnet IC writes the received data to the area at MB 0 of GM In this way the data at the owned area of GM MB 0 in the CUnet IC at SA 0 is copied to the areas at MB 0 of all the CUnet ICs Similarly when ST 1 data at MB 0 of GM is tr
9. term for the whole network system including individual equipment with the CUnet IC This guide describes the CUnet protocol that defines the basic operation and functions of the CUnet and its terminology TEP STECHNICA Co LTD CUnet 2 Outline of CUnet The following description is an outline of CUnet 1 2 3 4 5 6 7 8 9 10 11 12 13 A CUnet dedicated IC with CUnet protocol CUnet IC is provided to configure a CUnet The CUnet IC has memory The CUnet IC has a bus interface BUS I F connecting user CPU User CPU can read write access to memory embedded in the CUnet IC via the BUS I F The CUnet IC has a network interface network I F The Network I F connects to the network Multiple CUnet ICs are connected via the network The CUnet protocol copies data which a user CPU writes to memory of the CUnet IC to memo ries of all CUnet ICs connected via the network The CUnet protocol also copies data which a user CPU connected to other CUnet IC writes to memory of a CUnet IC to memories of all the CUnet ICs connected via the network Data copied to memory of CUnet IC can be read by all user CPUs accessing the CUnet IC The CUnet protocol helps all the CUnet ICs connected via the network to recognize mutually data in memory of each CUnet IC This allows the user to build a network in which the entire system operates as if it shares a piece of memory data although the
10. Constant cycle time calculated from formulae Constancy 3 Real time parallel processing 4 Hot swap This guide describes the basic functions and capabilities of CUnet by explaining the CUnet protocol When actually using the CUnet IC it is important to understand the functions and capabilities by referring to CUnet IC Manual CUnet Technical Guide and Let s Try CUnet booklet etc Manual updates product information technical reports etc are available at our Web site http www steptechnica com 28 Introduction Guide TEP SPECHNICA Co LTD Appendix CUnet protocol Version 1 00 This section describes the parameter specifications for the CUnet protocol version 1 00 used in the MK Y40 or the CUnet IC Network system Cyclic time sharing Network signal system RZ signal system Manchester Code Network communication system Half duplex multi drop Quality assurance at packet reception Format test CRC 16 and RZ test Length of frame LOF 151 at normal 256 at frame option Public frame count PFC 2 Final station initial value 63 Final station value variable or fixed Variable Allowable final station value 1 to 63 Phase count 4 START CALL RUN BREAK Number of connectable CUnet ICs 64 max Supported station address range 0 to 63 00H to 3FH Global memory size 512 bytes Memory block size 8 bytes 64 bits Memory block count 64 Maximum size of dataset at mail
11. Guide Preface This manual gives an overview of the concepts of the CUnet and defines various terms used in the system Be sure to read this manual before referring to each of manuals for the various ICs comprising the CUnet Target Readers This manual is for e Those who first build a CUnet e Those who first use StepTechnica s various ICs to build a CUnet Prerequisites This manual assumes that you are familiar with e Network technology e Semiconductor products especially microcontrollers and memory Caution e To users with CUnet User s Manual released before March 2001 Some terms in this manual have been changed to conform to International Standards E This manual has been prepared based on Standard English meeting the requirements of the International Organization for Standardization ISO and the American National Standards Institute ANSI This English manual is consistent with the Japanese document STD CUSTU V1 1J e Standard English is a trademark of Win Corporation TEP STECHNICA Co LTD CUnet TEP STECHNICA CO LTD Introduction Guide CONTENTS li AVNatisicoi eee de i Pode eA POTTS 7 2 Q tline OT IS ar renne ei ini a ee al 8 3 GUnerGoniguralion s ii sii lario aaa 9 4 CY CC TIMMS SSI ING eesi a riali 10 4 1 Standard Unit of MMes Ancauacat ae cates nc ata ila ale 10 4 2 Standard Unit of Time sharing allea liane 11 4 3 Cvele Configuiallon isa scr LA
12. I Keyword EYEE Public Frame Count PFC Public Frame Station Time ST Introduction Guide TEP SPECHNICA Co LTD 4 4 Cycle Time In the CUnet protocol a time required for one cycle is called Cycle Time As can be seen from the cycle configuration in Figure 4 3 Cycle Time can be calculated from the following equation 2 Equation 2 Cycle Time Frame Time x FS PFC 1 sec Keyword Cycle Time The CUnet protocol Version 1 00 defines PFC 2 LOF 151 When the final station ione in Figure 4 3 is 9 and TBPS is 12 Mbps 83 3 n sec the frame time of the cycle can be calculated from 151 9 1 x 2 x 83 3 26 83 Us resulting in a cycle time of 26 83 us x 12 322 0 us 4 5 Partitioning and Owning of Memory Within the memory on the CUnet IC memory area where memory data is shared is called Global Mem ory The Global Memory is often called GM for short The GM is partitioned into some Memory Blocks MB counted sequentially from 0 In the CUnet protocol the Address partitioned GM is corresponded to the station address SA y Owning of station at SA 0 by the memory block in accordance with the partitioning just like the first MB 0 corresponds to the SA 0 and the next MB 1 corresponds to the next SA 1 The CUnet protocol calls this partitioning Owning Fig 4 5 Owning of station at SA 3 gt GM Global Memory For example in the CUnet protocol the
13. LA 12 4 4 Cycle Time i 13 4 5 Partitioning and Owning of Memory 13 4 6 Data Sharing by Copying Data in Memory Block ii 14 4 7 Practical Side of Mail Sending Reception i 15 4 8 Management of Mail Sending Reception 16 4 9 Time Required to Send Receive Mail 16 5 Synchronization of GUnet Ci lai 17 5 SOTAR Tpha O aaa ea lai iii 17 5 2 MUA OM ASC xt fects ie as Ater ui Shree testa See ae Ba pda 18 5 9 RUN MAS O sonia e iano ils inn tel tatti 18 5 4 BREAK PNAS E ina EA AEA AAE 18 5 5 A Ga libration Of IMeis hh esilio ehe 18 6 Data Quality Assurance sacrale eked ree cet 19 6 1 Tests at Packet Reception cccccccccecessseececeeeeeeseeeeeeeeeeeesaaaeeeeeeeeseeseeeeees 19 6 2 Handshake for Individual Stations a siii opinion 20 6 2 1 Receive Status and Link Status 20 6 2 2 Practical Side of Establishing Handshake 21 6 2 3 DisclosureofSlalUsa aa eine ie elia ii dra i 21 6 2 4 Status in Practical User System uaar 22 6 2 5 JRECOVGI Vata aint an oe Acea 22 6 3 Packet Collisioniza shine ee esa hese tags aeake 23 6 3 1 Gall Packet Collision in CALL Phase noie 23 6 3 2 JaME cette o sioni hop hh SA ca Ana ht a dalia 23 7 lcreased Practicality iii ea noes bd atest ia ra 24 TI SO GEZ VIN sete tenere lidia id li a ii elle 24 T2 Expansion of Owned Area aene eanan anaa iaia 25 7 9 GCUneti lOG a E reali 26 8 Recomm
14. Sending Reception The CUnet protocol defines that the CUnet IC must have all the management required to send receive the mail as follows 1 To manage division and concatenation of dataset 2 To manage use rights for public frame 3 To manage destination station i e whether or not the station exists 4 To manage how much available memory space remains in destination station 5 To manage whether or not the sending reception of dataset by packets is successful retry and the number of times of retry 6 To manage time required to send receive mail i e setting and management of timeout and report of the time required to transfer mail These help the user system using the CUnet use the mail sending reception function simply Fig 4 7 In the CUnet protocol even if multiple stations start mail sending reception around the same time the CUnet IC can send receive mail corresponding to the public frame counts in a cycle simultaneously If the number of mail exceeds that of public frame counts the CUnet IC starts sending from the station address SA with the minimum SA value Because this priority rotates if the station with the minimum SA value continues to send mail the station with a greater SA value needs not wait for sending mail endlessly In addition if a station starts to send mail to an other station that is already sending mail the mail from other station must be waited until the already sent mail is terminated 4 9
15. Unet protocol changing the value of the FS to smaller one is called reduced resizing and changing the value to a greater one is called increased resizing or expanded resizing In a CUnet with three stations at SA 0 SA 1 and SA 7 if the user system executes reduced resizing for FS 1 the station at SA 7 cannot be given a timing for sending a packet in a cycle and is forced to leave the network to stop If the station at SA 7 starts again it cannot enter the network because it cannot given a timing for sending a packet in a cycle At this time the station at SA 7 transits to the BREAK phase To make the station reenter the network the station at SA 0 or SA 1 must execute expanded resizing of FS 7 or greater Keyword Resizing Reduced resizing Increased resizing Expanded resizing 24 TEP SPECHNICA Co LTD Introduction Guide 7 2 Expansion of Owned Area In CUnet one CUnet IC has one SA and owns one memory corresponding to the SA described in 4 5 Par titioning and Owning of Memory and 4 6 Data Sharing by Copying Data in Memory Block The CUnet protocol simultaneously allows SA 0 SA 1 SA 4 SA 63 Station Station Station Station CUnet to own one memory block corre sponding to the SA and associated multiple memory blocks This is called expansion ST 0 of owned area CP The CUnet IC enabling expanding owned area has a function to set the own width OWN wi
16. ained in the packet sent from SA xx allowing the link status to indicate OK Receive Link O O If an error occurs at the reception of the packet sent from SA yy both of the receive status and link status for SA yy indicate NG Receive Third cycle The CUnet IC checks that packet previously sent is incorrectly received based on SA yy NG k the receive status of SA xx PEE EEE EEES A i E contained in the packet sent Receive from SA xx allowing the link O Xx status to indicate NG Because the packet from SA xx could be received correctly the receive status is kept unchanged indicating OK ICI means Receive Link link is not established O O Fig 6 Concepts of the Receive Status and Link Status 6 2 3 Disclosure of Status The CUnet protocol defines that the CUnet IC must disclose the receive status and the link status using a flag bit so that the user CPU can read the statuses By reading the status flag bit in the CUnet IC the user system using CUnet can recognize the latest status of memory data sharing and also can determine whether or not data quality is assured by the CUnet protocol as follows 1 Flag bit indicating the receive status is ON The flag bit assures that memory block MB data corresponding to the status of global memory GM is received by the latest cycle 2 Flag bit indicating the link status is ON The flag bit assures that MB data corresponding to
17. ansmitted from the station at SA to the net work and is copied to all the areas at MB 1 on the CUnet When ST 2 the data from SA 2 is similarly sent to be copied When ST 3 the data from SA 3 is similarly sent to be copied When ST 63 the data from SA 63 is also sent to be copied The sequence of copy ing is executed in accordance with the passage of the frame In this way when one cycle is completed GM data in all the CUnet ICs connected via the network becomes the same The CUnet cycle continues automatically allowing the user program controlling the user CPU to share the data through the memory like GM When ST 0 data at MB 0 in the station at SA 0 is copied to other stations ie RE When ST 1 data at MB 1 in the station at SA 1 is copied to other stations SA SA 7 63 3FH 00H When ST 63 data at MB 63 3FH in the station at SA 63 is copied to other stations Fig 4 6 Principle of Data Sharing TEP SPECHNICA CO LTD Introduction Guide 4 7 Practical Side of Mail Sending Reception The CUnet protocol can share memory data In addition it also allows sending receiving the dataset between specific CUnet ICs using the mail sending reception function In the CUnet protocol the dataset is sent received as follows The dataset in the mail send buffer in the CUnet IC is divided into pieces of a size that the CUnet protocol defines as the dividing size Then the divid
18. ation of all the CUnet ICs connected via the network to always be maintained 1 When any station receives a packet from an other station while it is in the START phase and then transits to the RUN phase 2 When any station receives a packet from an other station while it is in the CALL phase and then tran sits to the RUN phase 3 When any station receives a packet with a minimum station address while it is in the RUN phase 4 When any station receives a packet with a minimum station address while it is in the BREAK phase Keyword Synchronization Calibration TEP SPECHNICA Co LTD Introduction Guide 6 Data Quality Assurance The CUnet protocol assures data to be copied and transferred when sharing memory data and transferring the mail dataset This section describes the quality assurance defined in the CUnet protocol 6 1 Tests at Packet Reception The CUnet protocol requires that the CUnet IC perform the following three tests concurrently when receiving packets This prevents garbage data that tends to occur in other communications 1 Pattern format test This test examines at the completion of packet reception whether the struc ture system of a packet starting with a specified start pattern meets the CUnet protocol 2 CRC 16 test Generally in an Ethernet LAN and bulk communications one CRC 12 block check code BCC is used for an array of thousands to tens of thousands of bits In contrast the CUnet pr
19. d cyclically In CUnet if the link is broken the lost packet is always recovered at the next cycle In the mail sending reception by the CUnet protocol if a mail send packet is lost during transfer due to external noise or an improper environment the mail send packet is recovered at the next cycle using the retry mentioned above which reforwards the previously sent mail packet Keyword Recovery 22 TEP SPECHNICA CO LTD Introduction Guide 6 3 Packet Collision In a communication network that sends packets via a network cable packet collisions must be avoided and communications must be system intensive The CUnet IC on the other hand uses a cyclic time sharing operation to synchronize the timings of all the CUnet ICs connected via the network Therefore in the RUN phase packet collisions never occurs How ever the following may cause packet collisions 1 Call packet collision in CALL phase 2 Jammer refer to 6 3 2 In case 1 the call packet collision is a transient event that does not affect network communication In case 2 jammer is an exception event caused by a defect or hardware failure Whatever the case CUnet will not affect the user system 6 3 1 Call Packet Collision in CALL Phase The sending interval of the call packet in the CALL phase is defined by the CUnet protocol according to the station address SA set for the CUnet ICs This prevents packets from colliding consecutively ev
20. dth meaning to set how STEHT ce many areas the CUnet IC owns 7 Figure 7 2 shows an example of the CUnet IC in which a station at SA 1 has OWN 3 The station at SA 1 sends MB data at ST 3 MB I to the network when the station Ex time ST is 1 and sends MB data at MB emer 2 to the network when ST 2 and sends MB data at MB 3 to the network when ST 4 ST 3 to each network In this way the D expansion of owned area can be achieved by a mechanism in which the sta tion at SA 1 sends data to the network as if it were the station at SA 2 and SA 3 Therefore an other CUnet IC cannot be set ST 63 to the station address SA 2 and SA 3 in Se Fig 7 2 superseded by the expansion of owned area In addition when sending mail between stations the station address SA 2 and SA 3 in Fig 7 2 that is superseded by the expansion of owned area cannot be specified as a destination because there is no mail receive buffer s in the SA that is superseded by the expansion of owned area Keyword Expansion of owned area OWN width OWN Fig 7 2 Expansion of Owned Area 25 SFE TECHNICA Co LTD CUnet 7 3 CUnetl O IC CUnet has the CUnet dedicated 1 0 IC CUnet I O IC enabling output of global memory GM data to the IO pin or input of the state of IC pin as GM data The CUnet protocol requires the CUnet I O IC to have the following functions and capabilities 1 Global mem
21. ed dataset is packetized into packets with source and destination station addresses attached and the packet is sent for each cycle The destination CUnet IC receives the packets and stores them sequentially the mail receive buffer When sending of all the divided dataset is complete the mail sending reception is complete In the CUnet protocol the mail is sent using the public frame which does not interfere with sharing memory data Fig 4 7 CUnet IC of SA xx CUnet IC of SA xx VERRA TE RR A Mail send buffer Mail receive buffer mail send buffer gt Passage of Cycle T y Designates destination station addresses and data size and starts sending Divides and receives data for each cycle using public frame During this process the CUnet IC controls the protocol N 4 User system needs not to CUnet IC controls the protocol manage and control 9 La i User system needs not to During this process the manage and control Notifies user system that mail reached by _ n an interrupt or a flag SS Fig 4 7 Practical Side of Mail Sending Reception O Keyword Mail Sending Reception Mail send buffer Mail receive buffer Notifies user system that mail sending is complete by an interrupt or a flag user system can check whether mail sending is successful and time required to send 15 SFE TECHNICA Co LTD CUnet 4 8 Management of Mail
22. en if one packet collision occurs For example if the CUnet ICs at SA 1 and SA 7 send call packets simultaneously packet collision occurs once but never occurs subsequently because the sending interval of the call packet of each CUnet IC differs In this case because there are two stations on the network if a call packet can be transmitted to the network only once the two stations transit to the RUN phase in which the CUnet normally operates 6 3 2 Jammer If there is a station that can send a packet but cannot receive a packet due to a failure even if the network is in the RUN phase the network cannot recognize the stations the station that can send a packet but can not receive a packet continues the CALL phase In this case even though a packet of other station in the RUN phase is being sent a call packet is send and thereby resulting in packet collisions The CUnet protocol calls such a station that can send a packet but cannot receive a packet due to a failure a Jammer Because the Jammer cannot receive a packet it cannot be forced to stop from the network side In this case the user must remove the Jammer or repair the failure The CUnet protocol defines that a CUnet IC detect a Jammer and warn the user system s about it Jammer Keyword Warn about Jammer Reference i AA ple a station that cannot receive a packet in RS232C RS458 or Ethernet LAN communica A jammer may exist whatever commu
23. ended Network Cables and Baud rate 27 9 Summary of this TAUIG Giniioio anita as eruarecanens ant 28 Appendix CUnet protocol Version 1 00 29 TEP STECHNICA Co LTD CUnet Figures amp Tables Fig 3 CUnet Configuration are zi eli selle ei orale di 9 Fig 4 1 RZ Return to Zero TBPS ciila iaia alii 10 Fig 4 3 Cycle COMIC URANO Reese alan ioni porre ol else 12 Fig 4 5 Partitioning and Owning of Memory 13 Fig 4 6 Principle of Data Sharings tela ii el 14 Fig 4 7 Practical Side of Mail Sending Reception i 15 Fig 5 Phase Transition Wyo Unek iano il ii ii 17 Fig 6 Concepts of the Receive Status and Link Status eneee 21 Fig 7 1 Concept of OSI ZING aeneon a ll n ra 24 Fig 7 2 Expansion of Owned Area 25 Fig 7 3 Using Uncle o ig lire ii 26 Table 1 Baud Rates and Network Cable LengthS 27 TEP SPECHNICA Co LTD Introduction Guide 1 What is CUnet Information Sharing at the Collective Unconscious Collective Unconscious Network CUnet This is a new concept of communication that allows multiple stations connected to network to share memory data and send receive mail of dataset and allows the stations to use both simultaneously CUnet is a coined word that combines Collective Unconscious psychological term and Network CUnet is a registered trademark of StepTechnica Co Ltd CUnet is a generic
24. er and the format of signals propagated through the network is RZ Return to Zero Consequently 64 branches can be connected using a standard RS 485 based driver receiver without using DC component signals In this case the cable length is likely to be shorter than the value in Table 1 due to increase of dispersion of propagated signal energy Caution The network cable lengths in Table 1 are provided as a guide for each baud rate but performance is not guaranteed 1 A driver receiver based on RS 485 is commercially available Reta eae 2 LAN cables are available but the user can buy recommended shielded and flexible LAN cables from us 3 A pulse transfer suitable for 12 6 and 3 Mbps can be purchased from us 4 Network cable length can be extended by adding HUB s For details refer to User s Manual for HUB IC MKY02 Background information to help build a network is described in the CUnet Technical Guide For more information about how to select components or to get recommended components visit our Web site at www steptechnica com 27 SFE TECHNICA Co LTD CUnet 9 Summary of this Guide CUnet is a new communication concept that enables sharing of memory data and sending receiving of mail including dataset simultaneously Communication using the CUnet IC with CUnet protocol provides user systems with the following benefits 1 Assured data quality at lower cost 2
25. ide 6 2 2 Practical Side of Establishing Handshake The CUnet protocol also requires that a packet to be sent as described in 4 6 Data Sharing by Copying Data in Memory Block contain a receive status A handshake allowing the self station to recognize where the packet sent from the self station is copied to can be established by determining the receive status contained in each packet to be received from the other station during the first sending of packet and the sending of packet in the next cycle The CUnet protocol calls this a successful handshake by determining the receive status as link established and operates the link status Figure 6 shows the concepts of the receive status and link status CUnet IC of SA xx Passage of time CUnet IC of SA yy Status for SA yy SA xx OK Receive Link First cycle Receive Link x x When the packet from SA xx is received correctly the receive status for SA xx indicates OK SA yy NG Receive Link When the packet from SA yy is received correctly the receive SA xx OK O x status for SA yy indicatesOK So A In addition the CUnet IC checks that packet previously sent is O O correctly received based on the receive status of SA yy contained in the packet sent from SA yy allowing the link status to indicate OK Receive Link Second cycle The CUnet IC checks that packet previously sent is correctly received based on the receive status of SA xx cont
26. integer constants called frame length constant LOF Length of Frame and Final Station The Frame Time can be calculated from the following equation 1 based on the LOF Final Station and TBPs The Final Station is often called FS for short Equation 1 Frame Time LOF FS 1 x 2 x TBPSs sec Frame Keyword Frame Time Length of Frame LOF Final Station FS SFE TECHNICA Co LTD CUnet 4 3 Cycle Configuration One cycle defined in the CUnet protocol consists of frame s corresponding to the number of FS s counted from 0 and frame s corresponding to the number of Public Frame Count s PFC defined in the CUnet protocol To distinguish these frames the latter is called Public Frame In the CUnet protocol the cycle mentioned above is constantly repeated This cycle can be compared to an ordinary clock In the ordinary clock a second hand goes around the face of a clock once in 60 seconds so there are 1 to 59 seconds at each position The cycle in the CUnet protocol on the other hand a Station Time ST beginning with 0 is used to represent the time each time a frame which is a standard unit of time sharing goes by For example a time after three frame times elapsed from 0 ST ST 0 is 3 ST or ST 3 Figure 4 3 shows a cycle configuration in which FS 9 and Public Frame Count PFC 2 Public frame Frame Fig 4 3 Cycle Configuration
27. memory data exists in each CUnet IC The CUnet protocol can share memory data In addition it also allows sending the dataset between specific CUnet ICs using mail sending reception function The dataset can be sent to a mail receive buffer of the destination CUnet IC by instructing mail sending reception after writ ing dataset to mail send buffer that the CUnet IC controls Keyword CUnet protocol CUnet IC Bus interface BUS I F Network interface network I F Network Share memory data Mail sending reception TEP STECHNICA cO LTD Introduction Guide 3 CUnet Configuration The CUnet consists of multiple user equipments with a CUnet dedicated IC CUnet IC and a network connecting these equipments The CUnet protocol defines half duplex multi drop connection as com munication mode If half duplex mode allowing sending and receiving of serial communication signals between the CUnet ICs is used the CUnet can be used with many types of network cables The user can choose between coaxial cable optical fiber cable etc according to the purpose and environment In addi tion to the network cable the CUnet network requires differential driver receiver components TRX that receive send serial communication signal Fig 3 The CUnet protocol defines each CUnet IC connected via the network and equipment with the CUnet IC as a station Each station connected via the network must be assigned an individual Station Addre
28. nication media including CUnet is used For exam tions sends a packet without detecting that other communication is running it can disturbs the network 23 SFE TECHNICA Co LTD CUnet 7 Increased Practicality 29 66 To increase the practicality of CUnet the CUnet protocol defines resizing expansion of owned area and CUnet dedicated I O IC CUnet I O IC 7 1 Resizing The CUnet protocol provides an initial value for the constant called Final station FS described in 4 2 Standard Unit of Time sharing For example the initial value in the CUnet protocol version 1 00 is 63 3FH In a user system with only two stations at SA 0 and SA 1 the network is not used during frames from SA 2 to SA 63 that configure a cycle In this case if the value of the final station is changed to 1 the user can use CUnet with the most effective cycle As just mentioned changing the value of the FS is called resizing in the CUnet protocol The frame time varies depending on this resizing as shown in equation 1 in 4 2 Standard Unit of Time sharing Fig 7 1 E Packet of cycle when FS 63 Cycle time Public frame Network unused time SA 1 Packet on network m Packet of cycle when FS 1 Cycle time Public frame Passage of time Fig 7 1 Concept of Resizing The CUnet protocol also defines that resizing be possible In the C
29. o tocol uses CRC 16 BCC which provides better performance than the CRC 12 for one packet an array of hundreds to thousands of bits This BCC is examined at the completion of packet reception 3 Validity test of RZ signal format RZ test The packet of serial communication signals consists of a pulse array for RZ Return to Zero or Manchester code described in 4 1 Standard Unit of Time The CUnet protocol examines received packets in bit units to check that the RZ format is maintained O Keyword Perform three tests concurrently Pattern format test CRC 16 test Validity test of RZ signal format RZ test Reference Generally although the test and correction concepts are used in serial communications ere rag S correction is completely different from test Correction restores damaged packets It is effective if data like consecutive voice data can have a certain error level garbage data However it is not suitable for CUnet The CUnet protocol only performs tests and dis cards all received packets failing the tests SFE TECHNICA Co LTD CUnet 6 2 Handshake for Individual Stations If a common and popular communication mode i e the broadcasts on the Ethernet LAN is used data sent from one station can be received by other multiple stations In this case however the user system cannot be assured that the multiple stations received the data correctly If the user system want
30. ory or a register corresponding to it 2 The capabilities other than mail sending reception function 3 The same functions and capabilities to support the phase transition and synchronization as those of the CUnet IC 4 The same functions and capabilities to assure the data quality as those of the CUnet IC Building a CUnet by combining the CUnet IC with the CUnet I O IC can achieve remote I O via GM data enabling all stations with CUnet ICs to read the GM to recognize the state of the IC pins of the stations with the CUnet I O IC Combining CUnet ICs with the CUnet I O IC to build the CUnet increases the practical ity and compatibility with the user system s Fig 7 3 7 Half duplex multi drop network A termination resistor is connected to both ends of the cable TRX TRX TRX gl e CUnet IC CUnet I O IC CUnet IC CUnet I O IC CUnet IC User CPU Input Output User CPU Input Output User CPU User equipment 1 YO A User equipment 2 V 0 B User equipment 3 All the user CPUs of user equipments 1 2 and 3 can reference I O A and I O B input states via memory data User CPUs of user equipments 1 2 and 3 can control the I O A and I O B output states L Fig 7 3 Using CUnet I O IC O Keyword CUnet 1 0 IC Remote I O 26 TEP SPECHNICA cCO LTD Introduction Guide 8 Recommended Network Cables and Baud rate In the CUnet protocol as described in 3 CUnet Configuration if the
31. s such an assurance in a common and standard communication mode the user system must get an answer Answerback indicating that the data was received after being sent To get the answer back individually multiple stations must perform a peer to peer handshake communication individually If communication is multiple stations to multiple stations the handshake communication must be performed station count 1 x station count times The CUnet protocol on the other hand assures a multiple stations to multiple stations handshake communication O Keyword Peer to Peer Handshake Multiple stations to multiple stations handshake communication 6 2 1 Receive Status and Link Status The CUnet protocol requires that the CUnet IC have two types of status called Receive Status and Link Status These statuses exist individually for final stations The receive status indicates that receiving of data from other stations is successful The link status indi cates that the previous data sent from the self station reached other stations correctly In other words it indi cates that the handshake is established The receive status and the link status are initialized at the timing of sending a packet described in 4 6 Data Sharing by Copying Data in Memory Block and then managed until the timing of sending a packet from the next self station Recei Keyword eceive Status Link Status 20 TEP SPECHNICA Co LTD Introduction Gu
32. sending reception 256 bytes Count of mail send buffer 1 256 bytes Count of mail receive buffer 2 256 bytes each Partition size of dataset 8 bytes Management of queue for mail sending rights Priority rotation Mail sending reception protocol control REQ ACK NAK EOT handshaking and retry count 3 times 29 E North America Distributor Trans Data Technologies Inc 340 Arthur Ave Roselle IL 60172 Telephone 630 440 4075 Facsimile 630 539 4475 e mail info steptechnica us http www steptechnica us E Developed and manufactured by Step Tecnica Co Ltd 757 3 Shimo fujisawa Iruma shi Saitama 358 0011 TEL 04 2964 8804 FAX 04 2964 7653 http www steptechnica com info steptechnica com CUnet Introduction Guide A Guide to the CUnet Protocol Document No STD HLSSTU V1 1E Issued September 2008
33. ss which is often abbreviated as SA in the CUnet protocols Network The termination resistor Rt is connected to both ends of the cable Half duplex multi drop network TRX Dl g CUnet IC CUnet IC TRX og CUnet IC User equipment User equipment User equipment User equipment User equipment The CUnet IC itself equipment with the CUnet IC is called station SA must be assigned to each CUnet IC Fig 3 CUnet Configuration Keyword User equipment Half duplex multi drop connection Network cable Differential driver receiver components TRX Station Station Address SA SFE TECHNICA Co LTD CUnet 4 Cyclic Time sharing As mentioned in section 2 Outline of CUnet the CUnet protocol copies data which a user CPU writes to memory of the CUnet IC to memories of all CUnet ICs connected via the network This copying is actu ally performed if the user CPU does not write data to the memory of the CUnet IC In other words the CUnet protocol copies the data in the memory of the CUnet IC connected via the network For this copy ing the concept of cyclic time sharing of the CUnet protocol is important This section describes the cyclic concept of cyclic time sharing in items 1 to 4 and the concept of shar ing memory data by time sharing in items 5 and 6 and the concept of mail sending reception in items 7 to 9 1
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