Model 8901A - Camac-To-GPIB Interface
Contents
1. l THEORY OF OPERATION GENERAL The Model 8901A is a GPIB to CAMAC interface which is composed of two circuit boards The first board plugs into the control rightmost slot of the CAMAC mainframe and interfaces to the CAMAC station number N lines and LAM lines This board also contains the GPIB interface cir cuitry The second board provides the interface to the CAMAC Dataway It has registers to store the CAMAC commands sent by the GPIB control ler and drive the function F address A and write data W lines of the Dataway during a CAMAC cycle It also has the circuit to generate the CAMAC cycle timing and latch the read data R lines The 8901A circuitry can be broken down into logical subsections as shown in the block diagram The operation of each of these subsections is discussed here GPIB COMMAND DECODER At the heart of the 8901A is the GPIB command decoder When a command is put on the GPIB bus it must be interpreted by the 8901A and a decision must be made as to how if at all to respond to it The 8901A will respond to any of the following GPIB commands interface clear IFC serial poll enable SPE serial poll disable SPD my TALK address MTA my LISTEN address MLA Unlisten UNL and Untalk UNT The 8901A has four basic states Idle TALK mode LISTEN mode Serial poll mode These states are entered and exited as a result of one of the above GPIB commands The following table list2. The CLEAR and INITIALIZE signals will be turned on only during the first CAMAC cycle executed after the 8901A received that command The INHIBIT line will remain asserted until the 8901A is programmed to de assert it Caution changing the INHIBIT line will affect the state of the service request response programming Table 6 Z C and Command Control Bytes Send INITIALIZE Z Send CLEAR C Send CLEAR and INITIALIZE Assert INHIBIT I De assert INHIBIT also disables SRQ Single byte commands values specified in decimal with hex value given in 19 20 Commands to Individual Modules PROGRAMMING THE 8901A The 8901A transfers Function Subaddress Station or slot number and up to three bytes of data to tne CAMAC dataway when sending a CA MAC command These commands are often referred to as FAN FNA or Function code commands Table 7 Acceptable Values for FAN Commands Command Component Abbreviation Range of Values Function code F 0 31 Subaddress A 0 15 Station Number N 1 25 Normal stations typically occupy slots 1 23 Data bytes D1 D2 D3 0 255 each AND OTHER CAMAC MODULES General LISTEN TALK UNLISTEN GPIB Bus Actions The programming of the two types of commands described in the last section SETUP COMMANDS and CAMAC COMMANDS must be handled in slightly different manners This section outlines the mechanics and examples necessary to upload and execute these commands
3. CODE void caminit addr type int addr type if gpib board was never opened open it if gpibBd lt 0 if gpibBd ibfind GPIBO lt 0 return if addr gt 0 88 addr lt 29 pcTalk 1 0x20 addr pcList 1 0x40 addr do an interface clear ibsic gpibBd set timeout 3 sec ibtmo gpibBd 12 set type of controller ccType type if type 6010 address 6010 to listen ibcmd gpibBd pcTalk 2 send command string to the 6010 ibwrt gpibBd DEF6010 DEFCNT AAA A E TEXT Function void camo n f a d Purpose Do a 24 bit camac write cycle W1 W24 Input int n slot number of module int f funtion code int a address code long d data value to send CODE void camo n f a d int n f a long d char rw 40 init qxResp return value qxRet 0 if ccType 8901 address 8901 to listen ibcmd gpibBd pcTalk 2 send 24 bit normal mode command to 8901A decimal 100 ibwrt gpibBd d 1 MUST make the 8901A unlisten send unlisten amp untalk 25 ibcmd gpibBd _ 2 build command string with 3 bytes of data CAMAC W1 W24 rw 0 charjf rw 1 char a rw 2 char n rw 3 char d amp OxFFL rw 4 char d amp OxFFOOL gt gt 8 rw 5 char d amp OxFFOOOOL gt gt 16 address 8901A to listen ibcmd gpibBd
4. PURPOSE UNPACKING AND INSPECTION WARRANTY PRODUCT ASSISTANCE MAINTENANCE AGREEMENTS GENERAL INFORMATION This manual is intended to provide instruction regarding the setup and operation of the covered instruments In addition it describes the theory of operation and presents other information regarding its functioning and application It is recommended that the shipment be thoroughly inspected immedi ately upon delivery All material in the container should be checked against the enclosed Packing List and shortages reported promptly If the shipment is damaged in any way please notify the Customer Service Department or the local field service office If the damage is due to mishandling during shipment you may be requested to assist in contacting the carrier in filing a damage claim LeCroy warrants its instrument products to operate within specifications under normal use and service for a period of one year from the date of shipment Component products replacement parts and repairs are warranted for 90 days This warranty extends only to the original pur chaser Software is thoroughly tested but is supplied as is with no warranty of any kind covering detailed performance Accessory products not manufactured by LeCroy are covered by the original equipment manufacturers warranty only In exercising this warranty LeCroy will repair or at its option replace any product returned to the Customer Service Department or a
5. Proper programming of the 8901A requires an understanding of these modes To place the 8901A into LISTEN or TALK mode or to make it UNTALK or UNLISTEN GPIB level commands must be executed typically by the host computer Please refer to the manual for your GPIB controller card for information on setting GPIB devices to be listeners talkers etc Steps 1 and 3 in this section are of this type The C function for this operation when using NI 488 GPIB board level commands is ibemd This function sends command bytes to the GPIB controller The bytes contain information about the devices attached to the GPIB bus and specifies through the use of device addresses if they are to be placed in TALK or LISTEN mode or to UNTALK or UNLISTEN These bytes are also referred to as Interface Messages Here are the correct byte assignments for the command byte param eter used with ibemd Table 8 Byte values of GPIB Interface Messages Action Decimal Value of Command Byte Make 8901A LISTEN 32 8901A device address Make 8901A TALK 64 8901A device address Make Computer a GPIB LISTENER 32 Make Computer a GPIB TALKER 64 Send UNLISTEN 63 Send UNTALK 95 Uploading Command Byte s to the 8901A Procedure for 8901A Setup Commands Procedure for 2 and Commands A typical assignment of the 8901A address set via the front panel dip switches is simply 1 Thus the 8901A LISTEN and 8901A TALK bytes would become 33 and 64 respective
6. from an IBM PC using National Instruments PC II GPIB Card Language C Note These functions were created for a novice user although they assume the basic knowledge of C GPIB and CAMAC They are not optimized for speed but for ease of understanding MUST link the National Instruments gpib obj file Microsoft C versions are labeld MCIBx OBJ file x C S M L CODE J p include camgpib h extern int ibfind char extern int ibonl int int extern int ibtmo int int extern int ibsic int extern int ibcmd int char int extern int ibwrt int char int extern int ibrd int char int extern int ibsta status word GPIB error code extern int ibcnt number of bytes sent int gpibBd 1 device descriptor for the controller board char pcTalk 9 Talk O List 1 char pcList ListO Talk 1 int ccType 0 Type of controller 8901 or 6010 int qxRet status last camac command define DEF6010 DUMB ON CDMA OFF CFMT OFF WORD BINARY CORD LOFIRST CAMAC 2 define DEFCNT 59 je Z TEXT Function void caminit addr type Purpose Initialize the GPIB routines and the camac controller Input int addr GPIB Address of controller int type C8901 or C6010 Notes This function MUST be performed to setup CAMAC access If GPIB board cannot be opened this function will exit 1 your program
7. ong rw 0 d1 amp OxFF d3 lt lt 16 d2 lt lt 8 d1 qxRet 3 amp 3 return d F _ _ _ _ _ _ _ _ TEXT Function int camibk16 n f a count buffer Purpose Do a 16 bit block read cycle Input intn slot number of module intf funtion code inta address code int count number of data values to read Output int buffer array to store data into Return number of data values read CODE int camibk16 n f a count buffer int f a count buffer int retval char rw 40 init return data count value retval 0 block xfer mode is set in bytes count count 2 if ccType 8901 address 8901 to listen ibcmd gpibBd pcTalk 2 send 16 bit high speed mode command to 8901A decimal 106 28 ibwrt gpibBd j 1 MUST make the 8901A unlisten send unlisten amp untalk ibcmd gpibBd 2 build command string with 3 bytes of data CAMAC W1 W24 rw 0 charjf rw 1 char a rw 2 char n rw 3 char 0 rw 4 char O rw 5 char O address 8901A to listen ibcmd gpibBd pcTalk 2 send command string to the 8901A F A N D1 D2 D3 ibwrt gpibBd rw 6 address 8901A to talk to execute the CAMAC cycle ibcmd gpibBd pcList 2 read a block of data from the 8901A ibrd gpibBd char buff
8. another SRQ will be issued immediately A Acceptor Handshake Address Switch B Block Transfer Byte Order Jumpers C CAMAC Commands CAMAC Cycles CAMAC Standard Clear Initialize and Inhibit Customer Service D Data Readout F FAN Commands G GPIB Address GPIB Command Installation Instrument Drivers J Jumpers L Listen Listen Mode INDEX 32 13 12 15 19 32 12 19 21 23 33 20 32 31 15 17 15 23 32 M Maintenance Agreements P Programming Examples Q Q Response R Registers S Serial Poll Service Procedure Service Request Setup Commands Source Handshake Specifications SRQ Generation SRQ Setup Commands T Talk Mode Transfer Mode U Unlisten Uploading Command Warranty X X Response 12 17 20 24 33 11 20 21 33 45 46
9. inhibited Note the INHIBIT LED turns on when the appropriate control byte is uploaded A TALK must still be executed for before other modules can be Inhibited Sets the GPIB Address of the 8901A See Figure 1 on page 15 The 8901A resides in the two slots furthest right in a CAMAC mainframe and generates all CAMAC dataway signals in response to commands from a GPIB controller A standard GPIB connector on the front panel permits interconnection to any GPIB system This allows any GPIB controller to program settings read from or write to any standard CAMAC modules Packaging is in conformance with CAMAC standard RF shielded 2 module Power Required is 1 2A at 6 V 13 14 SETUP OF JUMPERS AND MECHANICAL SWITCHES GPIB Address Byte Order Jumpers INSTALLATION IN MAINFRAME INSTALLATION Before installation in a mainframe set the GPIB Address and Byte Order jumpers as described in this section Each device connected to the GPIB must have a unique address which the system controller uses to communicate with it The address of the Model 8901A is set by a DIP switch located under the GPIB connector on the front panel The switches are labeled AO A1 A2 A4 represent ing values of 1 2 4 8 16 respectively Valid GPIB address are 0 to 31 Figure 1 shows an address setting of 9 as an example Example GPIB Address Switch Settings Address 9 X X X 0 X X 1 AO AT A2 4 X indicates switch depress
10. mainframe has sufficient clearance at the top to permit adequate airflow For example when using the 8901A in the 8013A benchtop instrument mainframe air blocking baffles Models BFP 1 and BFP 2 should be used to ensure proper cooling Do not obstruct ventilation by placing papers or other objects on the top of the mainframe INTRODUCTION Instrument Drivers and Example Source Code Command Types 8901A SETUP COMMAND INFORMATION Transfer Mode Commands OPERATING INSTRUCTIONS The 8901A provides GPIB control of all instruments in a CAMAC main frame by transferring data uploaded via GPIB to the CAMAC dataway and by controlling the execution of CAMAC cycles Current versions of instrument drivers for the LabVIEWTM and LabWindows packages are available from the LeCroy WWW and FTP sites as well as some sample source code and control programs All 8901A sample software is not protected under the 8901A warranty Please also refer to the next chapter Programming CAMAC Modules for information on uploading and executing commands described in this section The GPIB controller may send the 8901A two basic types of commands 1 8901A Setup Commands These commands program the 8901A and do not involve the CAMAC dataway or other CAMAC modules 2 CAMAC Commands These commands are communicated through the CAMAC dataway for programming and operation of other instruments in the mainframe There are two categories of Setup C
11. modes the 8901A will transfer a block of data The 8901A will automatically initiate additional CAMAC cycles after downloading the current data word s CAMAC cycles will continue to be executed until the status line goes to 0 or until the GPIB controller terminates the transfer There are two basic types of block read modes in the 8901A The first one normal block read is provided for modules which cannot read out at full CAMAC speed 1 MHz In this mode a 35 usec delay plus GPIB overhead is added between each CAMAC cycle to slow down the transfer rate The other mode high speed block read runs as fast as the data is read out over the GPIB up to 2 usec per cycle When block mode transfers are terminated by Q 0 two additional bytes are sent to the GPIB controller A status byte with the X and Q data followed by a zero byte and EOI Note Ifthe GPIB controller terminates the transfer before Q 0 one additional cycle will be executed and the data will be left in the 8901A s registers To access this data it is necessary to send the CAMAC command F 0 A 0 and N 24 see next section and then readout the data word This is required since the 8901A is initiating the CAMAC cycles in block mode transfers At the end of each block transfer the 89014 is reset to the corresponding normal transfer mode A service request SRQ is a mechanism by which a GPIB compatible instrument can communicate to a computer that a particular cond
12. pcTalk 2 send command string to the 8901A F A N D1 D2 D3 ibwrt gpibBd rw 6 address 89014 to talk to execute the CAMAC cycle ibcmd gpibBd pcList 2 read data from the 8901A to update the and X status ibrd gpibBd rw 10 1st byte R1 R8 2nd byte R9 R16 3rd byte R17 R24 4th byte Q amp X if ibent qxRet int rw 3 amp 3 else if ccType 6010 build command string with 3 bytes of data CAMAC W1 W24 sprintf rw n 2d f 2d a 2d w 10ld rqx n f a d address 6010 to listen ibcmd gpibBd pcTalk 2 send command string to the 6010 ibwrt gpibBd rw 31 address 6010 to talk ibcmd gpibBd pcList 2 read data from the 6010 to update the and X status ibrd gpibBd rw 10 1st byte R1 R8 2nd byte R9 R16 3rd byte R17 R24 4th byte Q amp X if ibent 4 qxRet int rw 3 amp 3 ff nn sj t TEXT Function long cami n f a Purpose Do a 24 bit camac read cycle Input int n slot number of module int f funtion code int a address code Returns long R1 R24 value of data read CODE long cami n f a 26 intn f a long d d1 d2 d3 char rw 40 init return data value and qxResp return value d OL qxRet 0 if ccType 8901 address 8901 to listen ibcmd gpibBd pcTalk 2 send 24 bit normal mode command to 8901A decimal 100 ibwrt g
13. trans ferred by issuing a TALK LISTEN Unlisten or IFC command Again note that the 8901A must be placed in LISTEN mode before it will receive any information 11 CAMAC Cycle Execution CLEAR INITIALIZE and INHIBIT Block Transfer Mode Service Requests SRQ Serial Poll Front Panel LEDs 12 Table 1 Register Descriptions Register Name Register Description Contains Function code OR Setup Command Module Subaddress CAMAC station slot number Low data byte bits W1 W8 on CAMAC Dataway Middle data byte bits W9 W16 High data byte bits W17 W24 A CAMAC cycle is executed every time the 8901A is commanded to enter the TALK mode and a Service Request is not pending At the completion of the CAMAC cycle a DAV Data Valid will be asserted Every time a byte is accepted a new byte is made available When no more data is available the 8901A asserts End of Identity The 8901A can be programmed to generate CLEAR INITIALIZE 2 or INHIBIT 1 signals on the dataway when a CAMAC cycle is executed The C and Z registers are cleared after the completion of the next CAMAC cycle The INHIBIT register will remain set until it is programmed off The 8901A can be programmed to do a high speed block transfer of 8 16 or 24 bit words from CAMAC modules with read and increment capability Following module addressing and the appropriate control byte see Operating Instructions a TALK command will start the 89
14. 01A to read one two or three bytes of data and automatically initiate another CAMAC cycle Approximately 2 usec later a programmable 40 usec delay can be used for slow modules new data is available to be read CAMAC cycles will continue to be executed until a Q 0 end of memory condition causes the 8901A to stop executing CAMAC cycles and exit the transfer mode The 8901A can be programmed to operate in SRQ mode In this mode a Service Request will be issued after a specific condition occurs on the CAMAC dataway involving the dataway LAM Q and X lines After issuing a service request a Serial Poll must be performed The 8901A will send the status of the individual LAM X and Q lines terminat ing the Service Request after the controller reads the status byte Note For a LAM generated Service Request the LAM must be cleared or disabled before the poll is taken or else another service request will immediately be issued TALK indicates when 8901A is a GPIB Talker LISTEN indicates when 8901A is a GPIB Listener SRQ Enable indicates when 8901A is enabled to carry out Service Requests X Response indicates a valid command was accepted by the addressed module Q Response indicates a valid data transfer or valid test within the mainframe GPIB Device Address Switch General Look at Me indicates when any CAMAC modules sets LAM line often used to generate a Service Request INHIBIT indicates when CAMAC dataway is
15. CUMENTATION DISCREPANCIES SERVICE PROCEDURE LeCroy is committed to providing state of the art instrumentation and is continually refining and improving the performance of its products While physical modifications can be implemented quite rapidly the corrected documentation frequently requires more time to produce Consequently this manual may not agree in every detail with the accompanying product and the schematics in the Service Documentation There may be small discrepancies in the values of components for the purposes of pulse shape timing offset etc and occasionally minor logic changes Where any such inconsistencies exist please be assured that the unit is correct and incorporates the most up to date circuitry Products requiring maintenance should be returned to the Customer Service Department or authorized service facility If under warranty LeCroy will repair or replace the product at no charge The purchaser is only responsible for the transportation charges arising from return of the goods to the service facility For all LeCroy products in need of repair after the warranty period the customer must provide a Purchase Order Number before any inoperative equipment can be repaired or replaced The customer will be billed for the parts and labor for the repair as well as for shipping All products returned for repair should be identified by the model and serial numbers and include a description of the defect or failure name a
16. OPERATOR S MANUAL MODEL 8901A CAMAC TO GPIB INTERFACE 2016 LeCroy Innovators in Instrumentation Corporate Headquarters 700 Chestnut Ridge Road Chestnut Ridge NY 10977 6499 Tel 914 578 6013 Fax 914 578 5985 E mail Irs_sales lecroy com Irs_support lecroy com Copyright July 1997 LeCroy is a registered trademark of LeCroy Corporation All rights reserved Information in this publication supersedes all earlier versions CE CONFORMITY CONDITIONS FOR CE CONFORMITY Since this product is a subassembly it is the responsibility of the end user acting as the system integrator to ensure that the overall system is CE compliant This product was demonstrated to meet CE conformity using a CE compliant crate housed in an EMI RFI shielded enclosure It is strongly recommended that the system integrator establish these same conditions INSTALLATION SPECIFICATIONS CAUTION Crate power should be turned off during insertion or removal of modules to avoid possible damage caused by momentary misalignment of con tacts The information contained in this manual is subject to change without notice The reference for product specification is the Technical Data Sheet effective at the time of purchase TABLE OF CONTENTS 1 General Information Purpose 9 Unpacking and Inspection 9 Warranty 9 Product Assistance 9 Maintenance Agreements 9 Documentation Discrepancies 10 Service Procedures 10 2 P
17. a lines X and are latched in the 8901A S2 is asserted 125 nsec later for 250 nsec The cycle is termi nated 125 nsec after S2 goes away Busy is cleared and all drivers are disabled The sequencer described above determines which data byte is to read out The order of the first two bytes may be reversed by side panel jumpers The data is latched in the 8901A on every CAMAC cycle and generally read out immediately after the cycle completes However a special command F 0 A 0 N 24 is provided to allow readout of the latched data the CAMAC cycle is inhibited at a later time The X and Q responses are latched in the 8901A during the CAMAC cycle and read out in the response byte They are also used in the generation of SRQs and termination of block mode transfers 33 34 LAM LINES SRQ GENERATION The LAM lines are used by the SRQ generation circuit and can be read by the GPIB controller when it s conducting a serial poll A service request SRQ may be generated depending on how the 8901A is programmed on any of the following conditions a LAM is set by one of the CAMAC instruments or a X 0 or 0 response is detected during the execution of a CAMAC cycle When a service request is pending CAMAC cycles are inhibited until a serial poll is performed and the cleared However if the SRQ was caused by a LAM unless the LAM is cleared or the 8901A is disabled to generate SRQs on LAM before the serial poll is taken
18. ce Request Response Description Description Status byte with X and Q on bits 1 and 2 respectively LAM for slots 1 through 6 Slot 1 LAM is least significant bit LAM for slots 7 through 12 LAM for slots 13 through 18 LAM for slots 19 through 23 A service request by the 8901A will be cleared after the controller reads the status byte However if the request was caused by a LAM a service request will immediately be issued again unless SRQ on LAM is disabled in the 8901A or the LAM is cleared in the instrument s asserting it It is important to note that the 8901A cannot transfer any CAMAC commands to the dataway while any service request is pending CAMAC commands are communicated through the CAMAC dataway for programming and operation of other instruments in the mainframe There are two basic types The 8901A can be programmed to generate CLEAR INITIALIZE 2 or INHIBIT I signals on the dataway when a CAMAC cycle is executed These commands are visible to all instruments in the mainframe C Z and are all single byte commands please see the section Program ming the 8901A and other CAMAC Modules for programming instruc tions CAMAC modules may have different responses to these commands please check the user manual for information specific to your modules The Introduction to CAMAC Application Note AN 33 included at the end of this manual contains further information regarding standard use of the C and Z lines
19. ed Figure 1 On the side panel of the Model 8901A are two pair of jumpers labeled NORMAL and REVERSE These jumpers determine the order in which the data bytes are read out When the jumpers are set to normal the least significant byte of data is read out first in multi byte transfers When in the reverse byte position a 16 bit word is read out most significant byte first followed by the least significant byte If 24 bit transfer is selected the order is middle byte least significant byte and then most significant byte It is recommended that the reverse byte option only be used when the computer expects the MSB before the LSB in a 16 bit word Caution this jumper only controls the byte order for reading out of the 89014 It does not effect the data bytes uploaded to the dataway Write lines NORMAL setting byte readback order Byte 1 Byte 2 Byte 3 REVERSE setting byte readback order Byte 2 Byte 1 Byte 3 The 8901A is compatible with any standard CAMAC mainframe With the power off insert the 8901A into the Control Station location the two rightmost locations in the mainframe Modules may become damaged if inserted with power on due to momentary misalignment of the contacts Note CAMAC mainframes with an embedded controller like the Model DDC3000 may not contain a Control Station Connect a GPIB cable from the 8901A to the GPIB interface associated with your computer 15 16 Always ensure that the
20. er count number of 16 bit values read retval ibent 2 else if ccType 6010 6010 max of 8192 bytes it can block transfer if count gt 8192 count 8192 build command string to perform block read CAMAC W1 W16 sprintf rw n 2d f 2d a 2d cbls 4d rb n f a count address 6010 to listen ibcmd gpibBd pcTalk 2 send command string to the 6010 ibwrt gpibBd rw 27 address 6010 to talk ibcmd gpibBd pcList 2 read a block of data from the 6010 ibrd gpibBd char buffer count number of 16 bit values read retval ibcnt 2 return retval f TEXT Function int qxResp Purpose Returns the CAMAC Q and X response from the last camo or cami functions Returns Q response in bit 1 X response in bit 0 CODE 29 30 int qxResp return qxRet FE end of file l CAMGPIB H Purpose Header file for all files that use functions from camgpib c Language C a extern void caminit int addr int type extern void camo int n int f int a long d extern long cami int n int f int a extern int camibk16 int n int f int a int count int buffer extern int qxResp void FE end of file
21. ition exists without requiring the computer to readout any data There are three conditions occurring on the CAMAC bus which can be employed to cause the Model 8901A to issue a service request to the GPIB controller 1 When any individual LAM line is set 2 When Q is set 3 When X is set Table 4 lists the commands to send to the 8901A to set it up to generate a SRQ on the proper condition s Table 4 Service Request Response Commands Disable SRQ Enable SRQ on occurrence of LAM Enable SRQ on occurrence of Q 0 Enable SRQ on occurrence of LAM or Q 0 Enable SRQ on occurrence of X 0 Enable SRQ on occurrence of LAM or X 0 Enable SRQ on occurrence of Q 0 or X 0 Enable SRQ on occurrence of LAM Q 0 or X 0 NOTE All of these commands de assert INHIBIT Single byte commands values specified in decimal with hex value given in CAMAC COMMANDS The C 2 and Commands The GPIB controller must perform a serial poll of all devices after receiv ing a service request When the 8901A is polled it sends up to 5 bytes of information to the GPIB controller The first byte is a status byte which contains the current state of X and Q in bits 1 LSB and 2 respectively and bit 7 indicating whether or not the currently addressed 8901A was the device which requested service If bit 7 is equal to one the 8901A generated the request The next four bytes indicate the state of the LAM lines They are encoded as follows Table 5 Servi
22. ly Note All of the bytes above happen to have ASCII text equivalents e g decimal 32 is the space character decimal 65 is the letter Capital A Ibcmd can send multiple bytes so it is convenient to make the 8901A LISTEN in at the same time as making the Computer a TALKER The 8901A must be placed in LISTEN mode to receive any information Placing the 8901A into TALK mode will execute a CAMAC cycle Lastly and importantly the UNLISTEN action is used to latch data in the 8901A without executing a CAMAC cycle This is necessary for the execution of 8901A SETUP COMMANDS Step 2 of the examples below require the transfer of appropriate data to the 8901A In the NI 488 board level command language this is imple mented using the ibwrt function This function sends a stream of data to the 8901A This data of up to 6 bytes is typically packed into either an array of characters C programming language or is packed into a String variable Basic programming languages The conversion of from INTE GER decimal value into a character is often accomplished using the chr function See Procedures for Commands Sent to Individual Modules below for more instruction The following steps should be used to upload and execute 8901A setup commands All of these commands are defined by a single byte and consist of the Transfer Mode and SRQ commands listed in Tables 3 and 4 Place 8901A in LISTEN mode this step will cause the LISTEN lamp to ill
23. mmands In this mode the 8901A will alternately transfer one two or three 8 bit bytes as programmed as fast as the Listener can accept them at rates approaching 500 kilobytes sec and then initiate a new CAMAC acquisition cycle Not all CAMAC modules however support Block Read readout The Model 8901A is a direct replacement for both the LeCroy Model 8901 and 8901 100 Mod 100 In addition to all of the 8901 890 1 100 features the A version includes the generation of the GPIB EOI signal at the end of valid data a jumper to select the order in which data bytes are sent to the GPIB controller and a slow block mode transfer for instruments that cannot be read out at full CAMAC speed Registers in the 8901A Interface are sequentially loaded with data after it has been commanded to enter the LISTEN mode by the GPIB System Controller These registers store all the information necessary F A N W C Z I to generate standard CAMAC cycles see Table 1 The first byte received by the interface after it has entered the LISTEN mode contains either the CAMAC Function F Code or 8901A Setup information The second and sequential bytes accept respectively the CAMAC subaddress A Code station number N Code and three bytes of data Once these registers have been loaded the information will be retained until modified or power is turned off The loading process can be termi nated and re initialized after any number of bytes have been
24. n authorized service facility within the warranty period provided that the warrantor s examination discloses that the product is defective due to workmanship or materials and has not been caused by misuse neglect accident or abnormal conditions or operations The purchaser is responsible for the transportation and insurance charges arising from the return of products to the servicing facility LeCroy will return all in warranty products with transportation prepaid This warranty is in lieu of all other warranties express or implied includ ing but not limited to any implied warranty of merchantability fitness or adequacy for any particular purpose or use LeCroy shall not be liable for any special incidental or consequential damages whether in con tract or otherwise Answers to questions concerning installation calibration and use of LeCroy equipment are available from the Customer Service Department 700 Chestnut Ridge Road Chestnut Ridge New York 10977 64989 914 578 6030 LeCroy offers a selection of customer support services For example Maintenance Agreements provide extended warranty that allows the customer to budget maintenance costs after the initial warranty has expired Other services such as installation training on site repair and addition of engineering improvements are available through specific Supplemental Support Agreements Please contact the Customer Service Department for more information 10 DO
25. n or slot Number Low Data Byte bits W1 W8 Middle Data Byte bits W9 W16 High Data Byte bits W17 W24 The command loading procedure may be halted after any number of these bytes have been uploaded This is useful when only the function or Subaddress is changing as a program executes For example ifthe user plans to send an F 25 A 0 N 5 command followed by F 2 A 0 N 5 command only one byte of information needs to be uploaded the F 2 data Thus the F 2 A 0 N 5 command may be executed without uploading the A and N information immediately prior to executing the CAMAC cycle with a TALK command Procedure for Readout of Data into Computer To readback data placed on the dataway be a CAMAC module typically after an F 0 or F 2 is uploaded and executed follow the following procedure This is simply an extension of the last section Procedure for Commands to Individual Modules Place 8901A in LISTEN mode this step will cause the LISTEN lamp to illuminate Upload byte stream ex F 2 A 0 command string Make 8901A TALK turns off LISTEN lamp illuminates TALK light executes CAMAC cycle Issue Read command e g ibrd for NI 488 Step 4 will return data appropriate to the Transfer Mode previously programmed See Transfer Mode section including Table 3 23 24 PROGRAMMING EXAMPLE SAMPLE SOURCE CODE f m CAMGPIB C TEXT Purpose Functions to control the CAMAC bus via an 8901A or 6010
26. n LISTEN mode The GPIB protocol provides a handshake for all data transfers When a GPIB command is sent or the 8901A is in LISTEN mode the 8901A must indicate that it is ready to receive a transfer by asserting the RFD line The GPIB controller must then assert DAV when valid data is on the bus The 8901A can then read in the data It then asserts the DAC line to say the transfer is complete Bits 6 and 7 of the first byte the 8901A receives from the GPIB Talker after entering LISTEN mode is used to determine whether the byte is a command for the 8901A itself a global CAMAC command or a CAMAC command for a specific module Bits 1 5 are then latched in the appropri ate registers If itis a CAMAC F command for a particular instrument a sequencer is used to latch additional bytes in the following order A N W1 8 W9 16 W10 24 There are three global CAMAC commands Z and For each of these commands there is a corresponding line on the CAMAC Dataway which is driven by the 8901A whenever a CAMAC cycle is executed The command is asserted if its latched value is a 1 At the end of the CAMAC cycle the C and Z latch is reset to zero As described above the values for F A N and the Write data are latched when the information is sent from the GPIB controller When a CAMAC cycle is executed all of these lines are driven for the entire length of the cycle while Busy is asserted The latched values will not change until they are
27. nd phone number of the user In the case of products returned a Return Authorization Number is required and may be obtained by contacting the Customer Service Department at 914 578 6030 THE 8901A and the CAMAC STANDARD UPGRADE NOTES SPECIFICATIONS Internal Registers and Byte Descriptions PRODUCT DESCRIPTION The Model 8901A is a CAMAC module which provides GPIB access to a CAMAC mainframe CAMAC is an international standard for modularized instrumentation as defined by the ESONE Committee and the IEEE Standard 583 Its function is to provide a means by which a wide range of modular instru ments can be powered in a multi receptacle crate and interfaced to a computer The LeCroy Model 8901A CAMAC to GPIB IEEE 488 interface allows the CAMAC system configuration to be used with GPIB computer controllers Simple program instructions via the GPIB to registers in the Model 8901A select an individual instrument module within the CAMAC mainframe select any subaddress within that module and establish the function read write control This allows the user to handle the entire CAMAC mainframe of up to 23 individual instrument modules in the same manner as any ordinary single device connected to the IEEE 488 bus It is possible to interconnect up to 15 different CAMAC mainframes in this way The 8901A can be programmed to do a block transfer of all data within a CAMAC module to a GPIB Listener without additional intermediate co
28. ommands m Transfer Mode Commands m SRQ Service Request Configuration Commands These are all single byte commands Please see the section Programming the 8901A and other CAMAC Modules for programming instructions By sending the appropriate command byte see Table 3 the 8901A can be programmed to return 8 16 or 24 bit data words in either single or block word transfers over the GPIB bus In the case of multiple byte transfers data is sent based on the Byte Order Jumper setting When the byte order is set to NORMAL the least significant byte is sent first followed by the middle and high bytes In normal transfer modes not to be confused with the NORMAL jumper setting mentioned above the 1 2 or 3 data bytes are followed by a status byte containing the X response least significant bit and the Q response bit 2 along with the GPIB EOI status line which is asserted to indicate end of the data transfer When programmed for normal transfers the 8901A will await further commands after data is transferred Table 3 Transfer Mode Commands Block Read Normal Transfer High Speed Block Read 8 bit read 97 61 121 79 105 69 16 bit read 98 62 122 7 106 6 24 bit read 100 64 124 7 108 6 Single byte commands values specified in decimal with hex value given in LabVIEW and LabWindows are trademarks of National Instruments Inc 17 18 SRQ Setup Commands and Responses In block read
29. overwritten by anew command from the GPIB controller The commands for the 8901A determine how many bytes are to be read back whether anew CAMAC cycle should be executed when data is read out block mode and what conditions if any should cause SRQ to be asserted by the 8901A The latches for this information are cleared if an IFC is sent The block transfer enable flip flop also is cleared when a Q 0 is read in SERIAL POLL MODE TALK MODE SOURCE HANDSHAKE CAMAC CYCLE TIMING READ DATA X AND Q RESPONSES Serial poll is used by the GPIB controller to determine which device asserted SRQ Upon decoding the serial poll enable command the SPAS flip flop is set true putting the 8901A in serial poll mode When the controller then addresses the 8901A to TALK the serial poll status bytes are sent instead of data and CAMAC cycles are inhibited Bit 7 of the status bytes indicates the state of the SRQ line while bits 1 6 are used for data The first byte contains X and Q while the next 4 bytes contain the LAM status six slots byte starting with slot 1 The SRQ is cleared when all of the status is read out or when the 8901A receives a serial poll disable command When the 8901A is addressed to TALK and serial poll mode is not active two things occur First the 8901A enters the Talker active state This causes the direction of the GPIB buffers to be reversed since the 8901A must now drive the GPIB bus and it must disable the accep
30. pibBd d 1 MUST make the 8901A unlisten send unlisten amp untalk ibcmd gpibBd 2 build command string with bytes of data CAMAC W1 W24 rw 0 charjf rw 1 char a rw 2 char n rw 3 char 0 rw 4 char O rw 5 char O address 8901A to listen ibcmd gpibBd pcTalk 2 send command string to the 8901A F A N D1 D2 D3 ibwrt gpibBd rw 6 address 89014 to talk to execute the CAMAC cycle ibcmd gpibBd pcList 2 read data from the 8901A to update the Q and X status ibrd gpibBd rw 10 1st byte R1 R8 2nd byte R9 R16 3rd byte R17 R24 4th byte Q amp X if ibent 4 d3 long rw 2 d3 d3 amp OxFF d2 long rw 1 d2 d2 amp OxFF d1 long rw 0 d1 d1 8 OxFF d 43 lt lt 16 02 lt lt 8 d1 qxRet int rw 3 amp 3 else if ccType 6010 build command string with 0 data CAMAC W1 W24 sprintf rw n 2d f 2d a 2d w 0 rqx n f a address 6010 to listen ibcmd gpibBd pcTalk 2 send command string to the 6010 27 ibwrt gpibBd rw 22 address 6010 to talk ibcmd gpibBd pcList 2 read data from the 6010 to update the Q and X status ibrd gpibBd rw 10 1st byte R1 R8 2nd byte R9 R16 3rd byte R17 R24 4th byte Q amp X if ibent 4 d3 long rw 2 d3 d3 amp OxFF d2 long rw 1 d2 42 8 OxFF d1 d1
31. roduct Description The 8901A and the CAMAC Standard 11 Upgrade Notes 11 Specifications 11 Internal Registers and Byte Descriptions 11 CAMAC Cycle Execution 12 CLEAR INITIALIZE and INHIBIT 12 Block Transfer Mode 12 Service Requests SRQ 12 Serial Poll 12 Front Panel LEDs 12 GPIB Device Address Switch 13 General 13 3 Installation Setup of Jumpers and Mechanical Switches 15 GPIB Address 15 Byte Order Jumpers 15 Installation in Mainframe 15 4 Operating Instructions Introduction 17 Instrument Drivers and Example Source Code 17 Command Types 17 8901A Setup Command Information 17 Transfer Mode Commands 17 SRQ Setup Commands and Responses 18 CAMAC Commands 19 The C Z and Commands 19 Commands to Individual Modules 20 Programming the 8901A and Other CAMAC Modules 20 General 20 LISTEN TALK UNLISTEN GPIB Bus Actions 20 Uploading Command Byte s to the 8901A 21 Procedure for 8901A Setup Commands 21 Procedure for C Z and Commands 21 Procedure for Commands Sent to Individual Moduels 22 Procedure for Readout of Data into Computer 23 Programming Example Sample Source Code 24 5 Theory Of Operation General 31 GPIB Command Decoder 31 Acceptor Handshake 32 LISTEN Mode 32 Global CAMAC Commands 32 F A N CAMAC Commands Transfer Mode Serial Poll Mode TALK Mode Source Handshake CAMAC Cycle Timing Read Data X and Q Response LAM Lines SRQ Generation 6 Appendix AN 33 An Introduction to CAMAC 7 Index
32. s each of the commands and describes its effect on the 8901As state GPIB BUS GPIB COMMAND DECODER T T 1 E ACCEPTOR 0d 6 SERIAL SOURCE SRQ HANDSHAKE a HANDSHAKE GENERATOR KEY GPIB BUS COMMANDS gt CONTROL LINES 8901A gt DEVICE DEPENDENT MESSAGES 8 DATA COMMANDS B CONTROL GLOBAL FANW CAMAC CYCLE RESPONSE CAMAC COMMANDS COMMANDS TIMING CZ e CAMAC BUS 8901A Functional Block Diagram ACCEPTOR HANDSHAKE LISTEN MODE GLOBAL CAMAC COMMANDS F A CAMAC COMMANDS TRANSFER MODE 32 IFC Resets all registers in the 8901A and places it in the Idle state regardless of its current state SPE Causes the 8901A to enter Serial Poll mode SPD If the 8901A is in Serial Poll mode this command returns it to the Idle state It also clears a pending service request SRQ MTA If in Serial Poll mode the 8901A will output its SRQ status upon receiving its TALK address If not in Serial Poll mode receipt of MTA will cause a CAMAC cycle to be executed and TALK mode to be entered UNT Takes the 8901A out of TALK mode if it is active MLA Causes the 8901A to enter LISTEN mode so that it may accept CAMAC or setup commands UNL Places the 8901A into the Idle state if currently i
33. tor handshake circuit and enable the source handshake circuit Secondly the 8901A starts the execution of a CAMAC cycle Upon completion of the cycle the appropriate number of data bytes are sent to the GPIB Listener followed by the X and Q response byte which is sent with the EOI signal asserted Since the 8901A is in TALK mode the GPIB handshaking protocol reverses That is the 8901A is now the one to indicate when data is valid Three conditions must be met before it can assert DAV First it must be in TALK mode and ATN must be set false by the GPIB controller Also it must wait for the GPIB controller or Listener to assert RFD The last condition is that the CAMAC data must be latched into the 8901A during the CAMAC cycle When all of these conditions have been met the 8901A waits an additional 200 nsec before asserting DAV to allow time for the data to become stable on the GPIB bus When the listening device asserts DAC DAV is cleared and a sequencer is clocked to output the next byte This byte may be another data byte or a status byte If in block mode the status byte is suppressed and a new CAMAC cycle is initiated instead The CAMAC cycle starts when the 8901A is addressed to TALK or if it is in block mode transfer when the last data byte is read out The 8901A asserts the Busy line and enables the F A N W C Z and drivers Approximately 500 nsec later S1 is asserted for 250 nsec At the end of 51 all 24 bits of the CAMAC dat
34. uminate Upload command byte ex Decimal 106 to set the 8901A in 16 bit Normal Transfer mode Make 8901A UNLISTEN turns off LISTEN lamp and latches the command byte The following steps should be used to upload and execute the C Z and I commands Note When uploading the INHIBIT command in step 2 above the INHIBIT lamp will illuminate The CAMAC crate however does not receive this information until step 3 is completed 21 22 Procedure for Commands Sent to Individual Modules Place 8901A in LISTEN mode this step will cause the LISTEN lamp to illuminate Upload command byte ex Decimal 34 to upload the CLEAR byte command Make 8901A TALK turns off LISTEN lamp illuminates TALK light executes CAMAC cycle These commands do the work to program initialize readout etc all of your CAMAC plug ins These commands are often referred to as FAN FNA and Function code commands The following steps should be used to upload and execute these commands Place 8901A in LISTEN mode this step will cause the LISTEN lamp to illuminate Upload byte stream see below for example Make 8901A TALK turns off LISTEN lamp illuminates TALK light executes CAMAC cycle When assembling the byte stream pack the bytes in the following order into a buffer Table 9 Byte order for Uploading CAMAC Function Commands Byte Byte Name Byte Description Function Code Number Module Subaddress CAMAC Statio
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