LeCroy 8901A User manual

OPERATOR'S MANUAL
MODEL 8901A
CAMAC TO GPIB
INTERFACE
April 1987

LeCroy
Innovators in Instrumentation
Corporate Headquarters
700 Chestnut Ridge Road
Chestnut Ridge, NY 10977-6499
Tel: [phone], TWX: 710-577-2832
European Headquarters
Route du Nant-d'Avril 101
1217 Meyrin 1
Geneva Switzerland
Tel: [phone]
Copyright® April 1987, LeCroy. All rights reserved. Information In this
publication supersedes all earlier versions. Specifications subject to change

CAUnON
INSTALLATION
SPECIFICATIONS
Crate power should be turned off during insertion or removal
of modules to avoid possible damage caused by momentary
misalignment of contacts.
The information contained in this manual is subject to
change without notice. The reference for product specifica
tion is the Technical Data Sheet effective at the time of pur
chase.

TABLE OF CONTENTS
General Information
Purpose
Unpacking and Inspection
Warranty
Product Assistance
Maintenance Agreements
Documentation Discrepancies
Software Licensing Agreement
2 Product Description
General
Specifications
Commands
3 Installation
Setup of Jumpers and Mechanical Switches
Installation in Mainframe
7
7
Operating Instructions
Introduction
Setup Commands
Programming CAMAC Modules
Programming Example
9
9
11
12
Theory Of Operation
General
GPIB Command Decoder
Acceptor Handshake
Listen Mode
Global CAMAC Commands
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
21
21
22
22
22
22
22
22
23
23
23
23
24
24
24
6 Additional Information
Description of CAMAC 27

GENERAL INFORMATION
PURPOSE
UNPACKING AND
INSPECTION
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.
The Service Documentation, packaged separately, should be
consulted for the schematics, parts lists and other materials that
apply to the specific version of the instrument as identified by
its ECO number.
It is recommended that the shipment be thoroughly inspected
immediately upon delivery. All material in the container should
be checked against the enclosed Packing List and shortages re
ported promptly. If the shipment is damaged in any way, please
notify the Customer Service Department or the local field serv
ice office. If the damage is due to mishandling during ship
ment, you may be requested to assist in contacting the carrier in
filing a damage claim.
WARRANTY
LeCroy warrants its instrument products to operate within speci
fications 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. Software is thor
oughly 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 Depart
ment or an authorized service facility within the warranty pe
riod, 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 insur
ance charges arising from the return of products to the servicing
facility. LeCroy will return all in-warranty products with trans
portation prepaid.
This warranty is in lieu of all other warranties, express or im
plied, including but not limited to any implied warranty of mer
chantability, fitness, or adequacy for any particular purpose or
use. LeCroy shall not be liable for any special, incidental, or
consequential damages, whether in contract, or otherwise

General Information
PRODUCT ASSISTANCE
MAINTENANCE
AGREEMENTS
DOCUMENTATION
DISCREPANCIES
SOFTWARE LICENSING
AGREEMENT
Answers to questions concerning installation, calibration, and
use of LeCroy equipment are available from the Customer Serv
ices Department, 700 Chestnut Ridge Road, Chestnut Ridge,
New York 10977-6499, [phone], or your local field
service office.
LeCroy offers a selection of customer support services. For ex
ample, Maintenance agreements provide extended warranty that
allows the customer to budget maintenance costs after the initial
warranty has expired. Other services such as installation, train
ing, on-site repair, and addition of engineering improvements
are available through specific Supplemental Support Agreements.
Please contact the Customer Service Department or the local
field service office for details.
LeCroy is committed to providing state-of-the-art instrumenta
tion and is continually refining and improving the performance
of its products. While physical modifications can be imple
mented 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 as
sured that the unit is correct and incorporates the most up-to-
date circuitry.
Software products are licensed for a single machine. Under this
license you may:
• Copy the software for backup or modification purposes in sup
port of your use of the software on a single machine.
• Modify the software and/or merge it into another program for
your use on a single machine.
• Transfer the software and the license to another party if the
other party accepts the terms of this agreement and you relin
quish all copies, whether in printed or machine readable form,
including all modified or merged versions.

PRODUCT DESCRIPTION
GENERAL The Model 8901A is a CAMAC module which provides GPIB
access to a CAMAC mainframe.
CAMAC is an international standard for modularized instrumen
tation 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 instruments 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 com
puter controllers. For additional information on the IEEE 583
CAMAC standard, See Chapter 6.
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 ordi
nary single device connected to the IEEE-488 bus. It is possi
ble 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 addi
tional intermediate commands. In this mode, the 8901A will
alternately transfer one, two or three 8-bit bytes (as pro
grammed) as fast as the Listener can accept them (at rates ap
proaching 500 kilobytes/sec) and then initiate a new CAMAC
acquisition cycle.
The Model 8901A is a direct replacement for both the LeCroy
Model 8901 and 8901/100 (Mod 100) and will work with
LeCroy 6900 series CATALYST software. In addition to all of
the 8901-8901/100 features, the "A" version includes the gen
eration 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 instru
ments that cannot be read out at full CAMAC speed.
SPECIFICATIONS
Internal Registers
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 infor
mation necessary (F, A, N, W, C, Z, I) to generate standard
CAMAC cycles.
The first^byt^received by the interface after it has entered the
Listen mode contains either the CAMAC Function (F Code) or

Product Description
CAMAC Cycles
Clear, Initialize
and Inhibit
Block Transfer Mode
Service Requests (SRQ)
Serial Poll
Front Panel LED's
control information. The second and sequgiJtial_bytes_a£cept,
respectively, the CAMAC subaddress (A Code), station number
JJljJ Code) and three bytes of data for the"CAMAC write lines.
Once these registers have been loaded, the information will_be
XetaiiigdjintiLJ2iQdifieioi_poweru^^ the Gra^s-
tem controller must issue a Listen command in order to initiate
this loading procedure. The loading process can be terminated
after any number of bytes have been transferred by issuing a
Talk, Listen, Unlisten or IFC command.
A CAMAC cycle is executed every time the 8901A is com
manded 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 (EOI).
The 8901A can be programmed to generate clear (C), initialize
(Z), or inhibit (I) signals on the dataway when a CAMAC cycle
is executed. The C and Z registers are cleared after the com
pletion of the next CAMAC cycle. The inhibit register will re
main set until it is programmed off.
The 8901A can be programmed to do a high speed block trans
fer of 8-, 16-, or 24-bit words from CAMAC modules with
read and increment capability. Following module addressing
and the appropriate control byte, a Talk command will start the
890 lA to read one, two, or three bytes of data and automati
cally initiate another CAMAC cycle. Approximately 2 psec
later (a programmable 40 tisec delay can be used for slow mod
ules) new data is available to be read. CAMAC cycles will con
tinue 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 will issue a Service Request when a LAM is set by a
CAMAC module, or when a CAMAC cycle is executed and a
Q=0 or X=0 response is detected.
When the 8901A is polled, it sends up to five status bytes to the
controller, terminating the Request after the controller reads the
status byte. For a LAM-generated Service Request, the LAM
must be cleared or disabled before the poll is taken, or else an
other service request will immediately be issued.
Talk: indicates when 890lA is a Talker.
Listen: indicates when 890 lA is a Listener.

Product -Description
Srq Enable; indicates when 8901A is enabled td carry out Serv
ice Requests.
X Response: indicates a valid command was accepted in the
mainframe.
Q Response: indicates a valid data transfer or valid test within
the mainframe.
Look-at-Me: indicates when any CAMAC modules sets
"LAM" (a Service Request).
Inhibit: indicates when CAMAC dataway is inhibited.
GPIB Address Switch
General
Sets the GPIB Address of the 8901A
The 8901A resides in the two slots furthest right in a CAMAC
mainframe and generates all CAMAC dataway signals in re
sponse 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 set
tings, read from or write to any standard CAMAC modules.
Packaging: is in conformance with CAMAC standard, RF
shielded #2 module.
Power Required: is 1.2 A at +6 V.
COMMANDS
Service Request
(SRQ) Setup
Addressing the 8901A and presenting a setup byte determines
the condition which generates an SRQ (Table 1).
Table 1
- SRQ Setup
SRQ Condition
Setup Byte
LAM
65
(41)
Q=0 66
(42)
X=0
68
(44)
LAM or Q=0
67 (43)
LAM or X=0
69 (45)
Q=0 or X=0 70 (46)
LAM, Q=0 or X =0 71
(47)
Disable SRQ
64
(40)
Single byte commands -
values specified
in decimal
with hex value given in ()

Product Description
Transfer Mode
Addressing the 8901A and presenting a transfer byte determines
the data transfer mode carried out with the subsequent execute
(Talk) command (Table 2).
Table 2 - Transfer Mode Commands
Normal
Transfer
Block
Read
High Speed
Block Read
8-bit read 97
16-bit read 98
24-bit read 100
121 (79) 105 (69)
122 (7A) 106 (6A)
124 (70) 108 (60)
Single byte commands - values specified in decimal
with hex value given in ()
Common CAMAC
Commands
Addressing the 8901A and presenting it with the following byte
determines a command which will be executed with the next
Talk command (Table 3).
Table 3 - CAMAC Commands
Send initialize (Z)
Send clear (C)
Send clear and initialize
Assert inhibit (I)
Deassert inhibit (also disables SRQ's)
Single byte commands - values specified in decimal
with hex value given in ()
Execute
Addressing the 890lA and presenting a TALK command exe
cutes the previously presented CAMAC command.

INSTALLATION
SETUP OF JUMPERS
AND MECHANICAL
SWITCHES
GPIB Address
Before installation in a mainframe, it is desirable to set the
GPIB and byte order jumpers as follows:
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 un
der the GPIB connector on the front panel. The switches are
labeled A0,A1,A2,A3,A4 (representing values of 1,2,4,8,16 re
spectively). Valid GPIB address are 0 to 31. Figure 3.1 shows
an address setting of 5 as an example.
GPIB Address Switch Settings
X
X
X
X
X X
0
1
AO
A1 A2
A3
A4 -
(X indicates switch depressed)
Figure 3.1
Byte Order Jumpers
INSTALLATION IN
MAINFRAME
On the side panel of the Model 8901A are two pair of jumpers
labeled "NORMAL" and "REVERSE". These jumpers deter
mine 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 multibyte 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 se
lected, 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 8901A. It does not effect
the "write" data.
The 8901A is compatible with any CAM AC mainframe.
With the power off, insert the 8901a into the Control Station
location (the two rightmost locations in the mainframe).
Connect a GPIB cable from the 8901A to the GPIB interface
associated with your computer.
Always ensure that the mainframe has sufficient clearance at the
top to permit adequate airflow. During operation in the 8013A

Installation
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.

OPERATING INSTRUCTIONS
INTRODUCTION
The 8901A provides GPIB control of all Instruments in a
CAM AC mainframe.
Waveform Catalyst
User Programming
SETUP COMMANDS
Transfer Mode Commands
LeCroy WAVEFORM CATALYST system provides digital stor
age scope operation of one or more CAMAC mainframes using
keystroke commands on a properly configured IBM PC or com
patible. No programming of the 8901A is required in this in
stance. See WAVEFORM CATALYST Operator's Manual.
The GPIB controller may send the 8901A two types of com
mands. The first type, setup commands, program the 890lA,
while the second type, CAMAC commands, is used by the
8901A to program the operation of instruments in the main
frame.
The setup commands are used to program the 8901A for the
desired transfer mode, and SRQ (service request) response. All
of these commands are single bytes; that is, the 890lA must
first be addressed to Listen, followed by the command byte.
By sending the appropriate command (see Table 1), the 8901A
can be programmed to return 8, 16, or 24-bit data words in
either single or block word transfers, whenever it executes a
CAMAC cycle. In the case of multiple byte transfers, the least
significant byte is sent first (if the byte jumpers are set to nor
mal - see Chapter 3 for more details). A CAMAC cycle is
executed every time the 890lA is addressed to Talk by the
GPIB controller. In normal non-block mode, after the 1, 2, or
3 data bytes have been read, a status byte is sent containing the
X response (least significant bit) and the Q response (bit 2)
along with the GPIB EOI status line asserted to indicate that this
is the end of the data to be transferred.
If a "block mode" read command had been sent, the 8901A
will automatically initiate another CAMAC cycle when the GPIB
controller has finished reading the current data word. CAMAC
cycles will continue to be executed until Q = 0 or the GPIB
controller terminates the transfer. There are two block modes
in the 8901A. The first one, "block read" is provided for mod
ules which cannot read out at full CAMAC speed (1 MHz). In
this mode, a 35 p.sec delay (plus GPIB overhead) is added be
tween 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 p,sec per cycle.
When block mode transfers are terminated normally (data read
until Q=0) two additional bytes are sent to the GPIB controller.
The first one is the status byte followed by a zero byte and EOI.

Operating Instructions
Note that in block mode transfers, since the 8901A is initiating
the CAMAC cycles, if the GPIB controller terminates the trans
fer 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 read out the data word. At
the end of the block transfer, the 8901A is set to the corre
sponding normal transfer mode.
Table 1 - Transfer Mode Commands
Normal
Transfer
Block
Read
High Speed
Block Read
8-bit read
16-bit read
24-bit read
121 (79) 105 (69)
122 (7A) 106 (6A)
124 (7C) 108 (6C)
Single byte commands - values specified in decimal
with hex value given in ()
Service Request Response
Commands
A service request (SRQ) is a mechanism by which a GPIB com
patible instrument can tell a computer that a particular condition
exists, without the computer having to read a byte of informa
tion. There are three conditions occurring on the CAMAC bus
which can cause the Model 8901A to issue a service request to
the GPIB controller: When a LAM is set, and when Q and/or
X indicate that invalid data/commands occurred during a trans
fer. Table 2 below lists the commands to send to the 890lA to
set it up to generate a SRQ on the proper condition (s).
The GPIB controller must perform a serial poll of all devices
after receiving 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 890lA
generated the request. The next four bytes indicate the state of
the LAM lines. They are encoded as follows:
LAM for slots 1 through 6 are in byte 2 (LAM 1 is LSB)
LAM for slots 7 through 12 are in byte 3
LAM for slots 13 through 18 are in byte 4
LAM for slots 19 through 23 are in byte 5
10

Operating Instructions
A service request by the 8901A will be cleared after the con
troller 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 execute any CAMAC commands while
any service request is pending.
PROGRAMMING CAMAC
MODULES
Commands Common
to All Instruments
Table 2 - Service Request Response Commands
Disable all SRQ's
Enable SRQ on occurrence of LAM
Enable SRQ on occurrence of Q=0
Enable SRQ on occurrence of X=0
Enable SRQ on occurrence of LAM or Q=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 deassert inhibit
Single byte commands - values specified in decimal
with hex value given in ()
64
(40)
65
(41)
66
(42)
68
(44)
67 (43)
69 (45)
70 (46)
71 (47)
The 8901A can be programmed to generate clear (C), initialize
(Z), or inhibit (I) signals on the Dataway when a CAMAC cycle
is executed. These commands operate on all instruments in the
mainframe without any further addressing. The clear and in
itialize 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 deassert it. Caution - changing the inhibit line will affect the
state of the service request response programming.
Table 3 lists the 8901A commands to perform these functions.
Table 3 - CAMAC Commands
Send initialize (Z)
Send clear (C)
Send clear and initialize
Assert inhibit (I)
Deassert inhibit (also disables SRQ's)
Single byte commands - values specified in decimal
11

Operating Instructions
Commands to an
Individual Instrument
To send a CAMAC command to a particular instrument the
GPIB controller must address the 8901A to Listen and load it
with the desired command information. If the first byte re
ceived by the interface after entering Listen mode is a valid
CAMAC function (F) code, (0 to 31) the 8901A assumes that
it is being sent a command sequence. The second byte ex
pected is the CAMAC subaddress (A) code. This is followed by
the CAMAC station number (N) code and up to three bytes of
data (least significant byte first). Once the command is sent to
the 8901A the information will be retained until modified or the
power is turned off. The GPIB system computer may terminate
the command loading procedure after any number of bytes have
been sent. In other words, if the only difference between the
last CAMAC command and the next one to be sent is the F
code, it is not necessary to send a new A, N, etc.
After loading the 8901A with the desired command, a CAMAC
cycle must be executed (by addressing the 8901A to Talk) to
send the command to the particular instrument.
PROGRAMMING
EXAMPLE
OUT x,y,...
IN bl,...bn,r
The following example illustrates the use of most of the 8901A
commands. The procedure uses the following typical sequence
of commands to control a LeCroy Model TR8837F Transient
Recorder.
Initialize the instruments upon power on
Enable LAM
Initiate sampling
Wait for trigger
Enable TR8837 for reading
Read data out in high speed mode
Read acquisition parameters
The implementation of this sequence (from the GPIB system
controller) is given below. The following notation is used:
indicates a transfer from the GPIB controller to the 8901A.
includes addressing the 8901A to Listen, sending the data
byte(s) to it, and then sending the GPIB Unlisten command.
It
indicates a n+1 byte transfer from the 8901A to the GPIB con
troller (bl ... bn are data bytes, r is the CAMAC response byte
12

Operating Instructions
with bits X and Q). It includes addressing the appropriate
8901A to Talk, reading the data byte(s) into the computer, and
then sending the GPIB Untalk.
TALK
indicates sending out the GPIB Talk address to the specific
8901 A. This is used to execute a CAMAC cycle when no data
is to be returned. The "IN" command may be substituted if
desired (e.g., to allow monitoring the CAMAC response bits X
and Q).
For purposes of this example, assume that the Model 8901A is
at GPIB address 1 and the Model TR8837F is in slot 3.
Initialize the Instruments
Initialize the crate by sending CAMAC Z
Execute CAMAC cycle by addressing 8901A to Talk
Program instrument's parameters by sending F(16),
A(0), N(3), dl, d2 (dl, d2 are the parameter
settings - see TR8837F manual for details)
Program 8901A to return 8 bits of data and the
CAMAC response byte
Execute CAMAC cycle and get CAMAC response
Enable LAM
Program 8 901A to set SRQ on LAM
Enable TR8837F to generate LAM by sending
F(26) (note that since the A and N have not
changed it is not necessary to resend them)
Execute CAMAC cycle by addressing 8901A to Talk
Initiate Sampling
Initiate sampling in the TR8837F with a F(9),
A(0),N(3) .
Execute CAMAC cycle by addressing 8901A to Talk
Wait for Trigger
At this point, the TR8837F is waiting for a trigger
(either external or from an F(25) sent to it). After the
trigger occurs and the module is finished acquiring data,
it will generate a service request.
Perform a serial poll to determine which instrument set LAM
(assuming there is more than one).
Disable the 8 901A from generating another SRQ
Send the GPIB serial poll enable command
GPIB bus transfers
(bytes in decimal)
OUT 33
TALK
OUT 16,0,3,dl,d2
OUT 97
IN bl, r
OUT 65
OUT 26
TALK
OUT 9,0,3
TALK
OUT 64
SPE
13

Operating Instructions
i
Read in the S status bytes
Send the GPIB serial poll disable command
Enable TR8837F for Reading
Clear LAM in TR8837F with F(10),A(0) ,N(3)
Execute CAMAC cycle by addressing 8901A to Talk
Enable read mode in the TR8837F with an F(17),
A(0),N(3)
Execute CAMAC cycle by addressing 8901A to Talk
Read Data
Set 8901A up for a high speed block read of
8-bit data words
Send F(2) to TR8837F - command to read data
Execute a CAMAC cycle and read all of the
data out (at end of data, module sets Q to 0,
the 8 901A then sends the response byte followed
by a 0 with the GPIB EOl bit set
Read Acquisition Parameters
Program the 8901A for a 16-bit data word
Tell the TR8837F to send its parameters
(F(0),A(0),N(0))
Execute CAMAC cycle and get 2 bytes containing
its acquisition parameters and the CAMAC
response byte
IN r,Ll,L2,L3,L4
SPD
OUT 10,0,3
TALK 1
OUT 17,0,3^
TALK
OUT 105
OUT 2,0,3
IN bl,...,bn,r,0
OUT 98
OUT 0,0,3
IN bl,b2,r
The following are working examples of programming the LeCroy
Model TR8828C 200 megasample/sec or TR8818 100
megasample/sec modular recorders using the Model 8901A and
the HP9836 desktop computer. HP BASIC Version 3.0 was
used for writing the code. Additional and complete function
commands for the digitizers and 890lA interface are contained
in the respective manuals.
Highlights of 8901A and Digitizer Programming:
The 8901A was set to a device address of 1 and called from HP
code as device 701, as shown below:
OUTPUT 701 USING B"; 17, 0, 8
The B" sets the format of data as BINARY. In this exam
ple, the F=17 command A=0, N=slot 8 sets the data pointer
back to the beginning of memory prior to reading out memory.
Sending a command to a digitizer is done the CAMO subrou
tine, lines 10000 to 10091. Note that upon programming a
14

Operating Instructions
module, a talk byte (line 10080) is sent to the 8901a to initiate
a cycle in the instrument mainframe. Function code, sub ad
dress, slot and bytes are predefined for setup, arming, triggering,
and reading setting setting memory pointer to beginning. Upon
entering the CAMO subroutine the bytes are sent over the
GPIB. Figure 1 illustrates the sequence of operations used to
program a recorder. Upon filling memory, a LAM (Look-At-
Me) flag is initiated to the 8901A for the digitizer slot. A serv
ice request (SRQ) is sent to the HP9836. A Serial Poll Service
Subroutine Qines 10100 to 10190) is initiated to handle the
SRQ, read 5 Status Bytes from the 8901A, and clear the LAM.
Data transfer is programmed in lines 10400 to 10419. Note
that since the TR8818 and TR8828C send out 2 bytes in the
mainframe, lines 10420 to 10449 are used to restore data and
convert data to integers, that can be plotted on the computer
screen.
In addition to programming modules using F-A-N commands in
the CAMO section, decimal bytes are used to program the
8901A module for the form of data to send over the bus. For
example, line 10413 programs the 8901A module for high speed
block reads of data by transmitting byte 106. When in block
read mode a single Function Command of 2 sent to the digitizer
initiates a data read from the recorder until memory has been
depleted.
The same output subroutine used for digitizers is used to pro
gram other LeCroy modules, such as a signal conditioner, clock
generator module, or gate and delay generator. The set of
function commands defined for each module are inserted to
obtain the desired state of operation.
A detailed listing of the above program follows along with com
ments explaining each subroutine and statement.
15

Operating Instructions
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!GRID ON OFF FLAG
I CLEAR SCREEN
!CLEAR GPIB
Sampling Period"
I TR8K_16ST:
THIS PROGRAM READS OUT A TR8828 USING AN 8K "TRANSFER"
IN HIGH SPEED BLOCK READ MODE 16 BIT TRANSFERS
*********** each point is read into a string variable ***********
! *********** then converted to an integer ****************
j
ON KBD GOSUB Ggrid
Flag=l
ASSIGN ®GPIB TO 701
!
PRINT CHR$(12)
GCLEAR
CLEAR 7
CLEAR 701
!
PRINT "
PRINT
PRINT " 1 = 5 ns 5 = 80 ns"
PRINT " 2 = 10 ns 6 = 160 ns"
PRINT " 3 = 20 ns 7 = 320 ns"
PRINT " 4 = 40 ns 8 = EXT CLK"
!
PRINT
PRINT
INTEGER Pretrig
INTEGER N.F.A.Datl,Dat2.Mask
A=0
!
INPUT "ENTER SLOT NUMBER",N
INPUT "ENTER SAMPLING PERIOD : ",Clk
IF Clk<l THEN 190
IF Clk>8 THEN 190
PRINT
INPUT " ENTER n/8 PRE-TRIGGER SAMPLES: ".Pretrig
IF Pretrig<0 THEN 230
IF Pretrig>8 THEN 230
INPUT "A(uto) or E(xternal) STOP TRIGGER ? :",Mode$
!
OUTPUT 701 USING "#,B":33
!
Clk=Clk-l
Datl=Pretrig+(Clk*16)
Dat2=0
F=16
GOSUB Camo
!
Start:
!
!
!
F=10
GOSUB Camo
F=24
GOSUB Camo
!DECLARE INTEGER
!GET SLOT NUMBER
!GET SAMPLE CLOCK
ISEND Z TO INITIALIZE CRATE
ISET UP CONTROL WORD (FIXED 16K MEMO
!CLEAR LAM
!DISABLE LAM
RY SIZE)
!WRITE OUT CONTROL WORD
16