Model 705 Interface Commands; Bus Management Lines - Keithley 705 Instruction Manual

Table 3-2 Model 705 Interface Function Codes
Code Interface Function
SHl Source Handshake Capability
AH1 Acceptor Handshake Capability
T6 Talker (Basic Talker, Serial Poll, Unaddressed
To Talk On LAG)
L4 Listener (Basic Listener, Unaddressed To Listen
On TAG)
SRI Service Request Capability
RLO
Remote/Local Capability
PPO No Parallel Poll Capability
DC1 Device Clear Capability
DTl Device Trigger Capability
co No Controller Capability
El Open Collector Bus Drivers
TEO No Extended Talker Capabilities
LEO No Extended Listener Capabilities
3.1.4 Model 705 Interface Commands
Interface commands controlling Model 705 operation are listed
in Table 3-3. Not included in the table are device-dependent
commands, which are covered in detail in paragraph 3.5.
Table 3-3. IEEE Command Groups
iANDSHAKE COMMAND GROUP
DAC = DATA ACCEPTED
RFD = READY FOR DATA
DAV= DATA VALID
JNIVERSAL COMMAND GROUP
ATN = ATTENTION
DCL= DEVICE CLEAR
IFC= INTERFACE CLEAR
LLO = LOCAL LOCKOUT
REN = REMOTE ENABLE
SPD = SERIAL POLL DISABLE
SPE = SERIAL POLL ENABLE
ADDRESS COMMAND GROUP
LISTEN: LAG = LISTEN ADDRESS GROUP
MLA = MY LISTEN ADDRESS
UNL= UNLISTEN
TALK: TAG =TALK ADDRESS GROUP
MTA= MY TALK ADDRESS
UNT=UNTALK
OTA = OTHER TALK ADDRESS
ADDRESSED COMMAND GROUP
ACG =ADDRESSED COMMAND GROUF
GET= GROUP EXECUTE TRIGGER
GTL= GO TO LOCAL
SDC = SELECTIVE DEVICE CLEAR
iTATUS COMMAND GROUP
RQS = REQUEST SERVICE
SRQ= SERIAL POLL REQUEST
STB = STATUS BYTE
END = EOI
3.2 IEEE-488 BUS LINES
As shown in Figure 3-1, the signal lines on the IEEE-488 bus
are divided into three groups: management, handshake and
data lines. The management and handshake lines ensure that
proper data transfer and bus operation takes place while the
data lines handle the bus information. Each of the bus lines are
low true.
TO OTHER DEVICES
lCOMPUTERi
I
DEVICE 4
ONLY ABLE I
TO TALK
(DMMI
DATA BUS
)
DATA B"TE
TRANSFEa
CONTROL
GENERA,
INTERFACE
MANAGELlENT
SRQ ? S-S ~~ALAGEMENT
REN
EOI
Figure 3-1 Bus Structure
3.2.1 Bus Management Lines
The bus management groups consists of five signal lines that
send certain single line bus commands and ensure an orderly
transfer of data. The five signal lines are:
1. ATN (Attention)-The state of the ATN line determines
whether information placed on the data bus by the con-
troller is to be considered data or a command.
3-3