Operation and Service Manual
Stanford Research Systems
Mainframe
SIM900
Revision 1.51 • July 19, 2005
Certification
Stanford Research Systems certifies that this product met its published specifications at the time
of shipment.
Warranty
This Stanford Research Systems product is warranted against defects in materials and workmanship for a period of one (1) year from the date of shipment.
Service
For warranty service or repair, this product must be returned to a Stanford Research Systems
authorized service facility. Contact Stanford Research Systems or an authorized representative
before returning this product for repair.
Information in this document is subject to change without notice.
Copyrightc Stanford Research Systems, Inc., 2003 – 2005. All rights reserved.
Stanford Research Systems, Inc.
1290–D Reamwood Avenue
Sunnyvale, CA 94089 USA
Phone: (408) 744-9040 • Fax: (408) 744-9049
www.thinkSRS.com • e-mail: info@thinkSRS.com
Printed in U.S.A.
SIM900 Mainframe
Contents
General Information iii
Safety and Preparation for Use . . . . . . . . . . . . . . . . iii
Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv
Notation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . vi
1 Operation 1 – 1
1.1 Introduction to the Instrument . . . . . . . . . . . . . 1 – 2
1.2 Getting Started . . . . . . . . . . . . . . . . . . . . . . 1 –3
1.3 Timebase . . . . . . . . . . . . . . . . . . . . . . . . . . 1 – 4
1.4 Configuration Switches . . . . . . . . . . . . . . . . . . 1–4
1.5 Activity Monitors . . . . . . . . . . . . . . . . . . . . . 1 – 6
1.6 SIM Interface Connector . . . . . . . . . . . . . . . . . 1 – 6
2 Remote Programming 2 – 1
2.1 Index of Commands . . . . . . . . . . . . . . . . . . . 2 – 2
2.2 Alphabetic List of Commands . . . . . . . . . . . . . . 2– 5
2.3 Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 – 9
2.4 Port Communications . . . . . . . . . . . . . . . . . . 2–10
2.5 Commands . . . . . . . . . . . . . . . . . . . . . . . . . 2 – 12
2.6 Register Model . . . . . . . . . . . . . . . . . . . . . . 2 –41
3 Communications Examples 3 – 1
3.1 Introduction to Communications . . . . . . . . . . . . 3 – 2
3.2 Streaming Example . . . . . . . . . . . . . . . . . . . . 3–4
3.3 Message-Based Example . . . . . . . . . . . . . . . . . 3 – 8
3.4 Combination Example . . . . . . . . . . . . . . . . . . 3 –16
4 Circuitry 4 – 1
4.1 Circuit Descriptions . . . . . . . . . . . . . . . . . . . . 4–2
4.2 Parts Lists . . . . . . . . . . . . . . . . . . . . . . . . . 4 – 6
4.3 Schematic Diagrams . . . . . . . . . . . . . . . . . . . 4 – 8
i
ii Contents
SIM900 Mainframe
General Information
Safety and Preparation for Use
Dangerous voltages, capable of causing injury or death, are
present in this instrument. Use extreme caution whenever theWARNING!
instrument covers are removed. Do not remove the covers while
the unit is plugged into a live outlet.
Line Voltage
The universal input power supply of the SIM900 accommodates any
voltage in the range 90 VAC to 260 VAC, with a frequencyin the range
47 Hz to 63 Hz.
Line Fuse
The line fuse is internal to the SIM900 and may not be serviced by
the user. If the Standby LED does not turn on when line power is
provided, contact Stanford Research Systems.
Line Cord
Service
The SIM900 has a detachable, three-wire power cord for connection
to the power source and to a protective ground. The exposed metal
parts of the instrument are connected to the outlet ground to protect
against electrical shock. Always use an outlet which has a properly
connected protective ground.
Do not attempt to service or adjust this instrument unless another
person, capable of providing first aid or resuscitation, is present.
Do not install substitute parts or perform any unauthorized modifications to this instrument. Contact the factory for instructions on
how to return the instrument for authorized service and adjustment.
The SIM900 Mainframe is not intended for hot-swapping applications. Be certain to switch power to Standby before inserting or
ejecting modules in the mainframe. Do not connect a module to the
remote port while power is on.
iii
iv General Information
Symbol Description
Alternating current
Caution - risk of electric shock
Frame or chassis terminal
Caution - refer to accompanying documents
Earth (ground) terminal
Battery
Fuse
On (supply)
Off (supply)
Symbols you may Find on SRS Products
SIM900 Mainframe
General Information v
Notation
The following notation will be used throughout this manual:
• Front-panel indicators are set as Overload.
• Remote command names are set as *IDN?.
• Literal text other than command names is set as OFF.
Remote command examples will all be set in monospaced font. In
these examples, data sent by the host computer to the SIM900 are
set as straight teletype font, while responses received by the
host computer from the SIM900 are set as slanted teletype font.
Command terminators explicitly sent by the host computer are set
with the symbol “”.
SIM900 Mainframe
vi General Information
Specifications
Performance Characteristics
Power Supplies Voltages ±15 VDC, ±5 VDC, +24 VDC
Regulation ±0.5 % (±15 V, ±5 V)
±2 % (+24 V)
Current limits 5 A max (+5 V)
3 A max (all others)
Power limit 70 W total, all voltages
Timebase Internal timebase 10 MHz VCXO, ±10 ppm
External connector Rear panel BNC
External input 10 MHz, 1 V to 5 V pp
Capture range ±50 ppm (±500 Hz)
Interfaces SIM ports 8 internal + 1 Remote
DB–15 (female)
Aux. RS-232 2; DB–9 (male) DTE
Host interface RS-232; DB–9 (female) DCE
GPIB (optional)
Eavesdrop RS-232; DB–9 (female) DCE
Indicator Lights Interface RS-232, GPIB
Operating Temperature 0◦C to 40◦C, non-condensing
General Characteristics
Timebase Internal, External Lock, External Fault
Activity 8 slots, Remote SIM,
Aux A, Aux B,
Mainframe, Data Send,
Data Receive, Data Error
Startup Script Enabled
Power On, Standby, Overload, Trip
Power 90 VAC to 260 VAC, 47 Hz to 63 Hz
150 W max
Weight 12.6 lbs
Dimensions 17.000W × 5.300H × 9.000D
Rack mount O900RM (optional)
SIM900 Mainframe
1 Operation
In This Chapter
This chapter describes the operation of the SIM900 Mainframe.
1.1 Introduction to the Instrument . . . . . . . . . . . . 1 – 2
1.1.1 Front Panel . . . . . . . . . . . . . . . . . . . 1 – 2
1.1.2 Rear Panel . . . . . . . . . . . . . . . . . . . . 1 – 3
1.2 Getting Started . . . . . . . . . . . . . . . . . . . . . 1 – 3
1.3 Timebase . . . . . . . . . . . . . . . . . . . . . . . . . 1 – 4
1.4 Configuration Switches . . . . . . . . . . . . . . . . 1 – 4
1.4.1 Baud Rate/GPIB Address . . . . . . . . . . . 1 – 4
1.4.2 Host Select . . . . . . . . . . . . . . . . . . . . 1 – 5
1.4.3 Clock Distribution Enable . . . . . . . . . . . 1 – 5
1.4.4 Startup Script Enable . . . . . . . . . . . . . . 1 – 6
1.5 Activity Monitors . . . . . . . . . . . . . . . . . . . . 1 – 6
1.6 SIM Interface Connector . . . . . . . . . . . . . . . 1 – 6
1 – 1
1 – 2 Operation
1.1 Introduction to the Instrument
The SIM900 Mainframe is the platform on which a SIM system is
assembled. The mainframe provides power, computer interfaces,
clock synchronization, and individual module status.
1.1.1 Front Panel
The SIM900 front panel consists of a power switch and a collection
of indicator lamps (see Figures 1.1).
Figure 1.1: The SIM900.
Figure 1.2: The SIM900 rear panel (shown with a full complement of
SIM modules).
SIM900 Mainframe
1.2 Getting Started 1 – 3
1.1.2 Rear Panel
The SIM900 rear panel is shown in Figure 1.2. In addition to the
host interface connector(s) and power entry module, the rear panel
contains an external timebase reference input, auxiliary RS-232 interfaces, and a window for access to SIM module rear panels.
1.2 Getting Started
The SIM architecture does not support hot insertion or extraction
of modules. Before installing or removing any SIM modules, the
mainframe power must be switched to “Standby.”
To install a module, align the back of the module with the black
guide-ramps in the mainframe slot. Ease the module in until the
connector begins to mate. Be careful to not apply pressure directly
on any module display; it is better to push along the upper part of
the edge of the module side covers until a positive “click” is heard.
At this time, the module will be fully mated and locked in place.
To remove a module, press firmly on the ejection button below the
module slot. When ejecting a double-wide module, the left-hand
button must be pressed to eject.
When the arrangement of desired SIM modules is installed, turn on
the mainframe power switch to begin operation.
SIM900 Mainframe
1 – 4 Operation
1.3 Timebase
The SIM900 Mainframe provides a common 10 MHz clock reference
to the SIM modules. By synchronizing clocks, low-frequency mixing products (beat tones) of independently running module clocks
is avoided. A common timebase also allows precision time and
frequency modules to be synchronized. This feature can be enabled or disabled using the rear-panel configuration switches (see
section 1.4.3) or with the CLKD remote command.
In a laboratory employing multiple SIM900’s or where a highprecision clock reference is desired, this feature can be extended by
synchronizing the mainframe(s) to an external 10 MHz reference. An
auto-detect circuit senses the presence of an AC signal at the TIMEBASE IN connector on the rear panel, and attempts to phase-lock the
internal oscillator to the applied signal. The TIMEBASE block of the
SIM900 front panel (see Figure 1.3) indicates the clock status as one
of three states:
Internal 10 MHz : No signal is detected at the timebase input, and the SIM900
internal oscillator is being used.
External Lock : The SIM900 detected an external clock reference and success-
External Fault : An external clock signal was detected, but the SIM900 failed to
The phase-locked loop has a capture range of ±10 ppm (±100 Hz),
and should lock reliably with input signals of 1 V to 5 V peak-topeak amplitude.
1.4 Configuration Switches
The rear panel DIP switches (see Figure 1.3) provide basic configuration of the SIM900 Mainframe host interface. The switches selecting
the remote interface are read only at power-up time, but may be
changed at any time.
1.4.1 Baud Rate/GPIB Address
The rightmost five (5) switches program either the default baud rate
for the “COMPUTER” RS-232 port, or the GPIB address.
The RS-232 default baud rate can be set to 1200, 9600, 19.2k, 57.6k, or
115.2k. Select one rate by setting that switch in the down position; if
no switch is selected or more than one is down, the SIM900 defaults
to 9600 baud and Error lights for several secondsafter power-up. The
host baud rate can be changed after power-up under remote program
fully phase-locked to it.
phase-lock to it.
SIM900 Mainframe
1.4 Configuration Switches 1 – 5
control (see the BAUD command), but will revert to the rear-panel
default after power cycling or a Device Clear (RS-232 hbreaki) signal.
For GPIB, the 5 switches set the binary-encoded bus address for the
SIM900. To add 2nto the address, set switch An in the lower position.
For example, to set the GPIB address to 19 (= 16 + 2 + 1) set switches
A0, A1, and A4 down (on).
1.4.2 Host Select
The next switch to the left of the Rate/Address field (position # 3)
selects the mainframe host interface: up selects RS-232, down selects
the (optional) GPIB interface.
1.4.3 Clock Distribution Enable
The next switch to theleft of the Host Select field(position #2) controls
the mainframe timebase distribution. When this switch is in the on
(down) position, the 10 MHz timebase is distributed to all 8 module
slots and the rear-panel Remote SIM port on pins 5 & 12. When the
switch is in the off (up) position, no clock signals are distributed, and
pins 5 & 12 on all SIM ports both idle at 0 V. In either case, all SIM
modules will continue to operate properly.
Figure 1.3: The SIM900 front and rear panels.
SIM900 Mainframe
1 – 6 Operation
Note that unlike the other DIP switch settings, the Clock Distribution
Enable switch is continuously monitored, and anychanges take effect
immediately (although they can be later overridden with the CLKD
remote command).
1.4.4 Startup Script Enable
The SIM900 has a 4000 byte non-volatile memory to store a sequence of remotecommands to execute upon power-up (the “Startup
Script”). In order for a stored script to execute automatically after
power-up, the left-most switch must be in the on (down) position.
When the script is enabled and executed, the front-panel indicator
flashes and then remains lit.
See section 2.5.8 for the remote commands to configure the startup
script.
1.5 Activity Monitors
The ACTIVITY section of the front panel monitors data transfer to
and from the mainframe. When bytes are received from any port,
the corresponding port indicator (1–8, Remote SIM, Aux A (RS-232)
or Aux B (RS-232)) flashes together with From SIM. When the mainframe transmits data to the host interface, Mainframe and From SIM
both flash as well.
When data is received at the mainframe host interface or transmitted
to one of the ports, To SIM flashes, along with the corresponding
port indicator.
If a communication error is encountered, Error will flash briefly.
1.6 SIM Interface Connector
The DB–15 SIM Interface connector carries all the power and communications lines between the mainframe and SIM modules. The
module-side of the interface is DB–15 male (plug), while the mainframe side is DB–15 female (socket). The connector signals are specified in Table 1.1
Note that all SIM modules are specified to operate with or without
the presence of the ±REF 10MHZ signals, so these lines are optional
in any cabling interface between the mainframe REMOTE SIM port
and a module.
SIM900 Mainframe
1.6 SIM Interface Connector 1 – 7
Direction
Pin Signal Src ⇒ Dest Description
1 SIGNAL GND MF ⇒ SIM Ground reference for signal
2 −STATUS SIM ⇒ MF Status/service request (GND=asserted, +5V=idle)
3 RTS MF ⇒ SIM HW Handshake (+5 V=talk; GND=stop)
4 CTS SIM ⇒ MF HW Handshake (+5 V=talk; GND=stop)
5 −REF 10MHZ MF ⇒ SIM 10 MHz reference
6 −5V MF ⇒ SIM Power supply (fast analog circuitry)
7
−15V MF ⇒ SIM Power supply (analog circuitry)
8 PS RTN MF ⇒ SIM Power supply return
9 CHASSIS GND Chassis ground
10 TXD MF ⇒ SIM Async data (start bit=“0”=+5 V; “1”=GND)
11 RXD SIM ⇒ MF Async data (start bit=“0”=+5 V; “1”=GND)
12 +REF 10MHz MF ⇒ SIM 10 MHz reference
13 +5V MF ⇒ SIM Power supply (digital & fast analog circuitry)
14 +15V MF ⇒ SIM Power supply (analog circuitry)
15 +24V MF ⇒ SIM Power supply (power circuitry)
SIM900 Mainframe
Table 1.1: SIM Interface connector pin assignments, DB–15
1 – 8 Operation
SIM900 Mainframe
2 Remote Programming
This chapter describes how to control the SIM900 Mainframe, and
any connected SIMs or generic RS-232 devices, from a host computer.
In This Chapter
2.1 Index of Commands . . . . . . . . . . . . . . . . . . 2 – 2
2.2 Alphabetic List of Commands . . . . . . . . . . . . 2 – 5
2.3 Introduction . . . . . . . . . . . . . . . . . . . . . . . 2 – 9
2.4 Port Communications . . . . . . . . . . . . . . . . . 2 – 10
2.5 Commands . . . . . . . . . . . . . . . . . . . . . . . 2 – 12
2.6 Register Model . . . . . . . . . . . . . . . . . . . . . 2 – 41
2.3.1 Device Clear . . . . . . . . . . . . . . . . . . . 2 – 9
2.3.2 Queues and buffers . . . . . . . . . . . . . . . 2 – 9
2.4.1 Message-based communication . . . . . . . . 2 – 10
2.4.2 Connection-based communication . . . . . . 2 – 10
2.4.3 Port map . . . . . . . . . . . . . . . . . . . . . 2 – 11
2.5.1 Command syntax . . . . . . . . . . . . . . . . 2 – 12
2.5.2 Examples . . . . . . . . . . . . . . . . . . . . 2 – 14
2.5.3 Communication commands . . . . . . . . . . 2 – 15
2.5.4 Configuration commands . . . . . . . . . . . 2 – 17
2.5.5 Eavesdropping commands . . . . . . . . . . 2 – 21
2.5.6 Serial commands . . . . . . . . . . . . . . . . 2 – 22
2.5.7 Status commands . . . . . . . . . . . . . . . . 2 – 24
2.5.8 Script commands . . . . . . . . . . . . . . . . 2 – 28
2.5.9 Housekeeping commands . . . . . . . . . . . 2 – 31
2.5.10 Interface commands . . . . . . . . . . . . . . 2 – 34
2.6.1 Control registers . . . . . . . . . . . . . . . . 2 – 41
2.6.2 Status registers . . . . . . . . . . . . . . . . . 2 – 44
2 – 1
2 – 2 Remote Programming
2.1 Index of Commands
symbol definition
p Port number
i,j Integers
z Literal token
b Multi-byte (string) block
(?) Required for queries; illegal for set commands
var Parameter always required
{var} Required parameter for set commands; illegal for queries
[var] Optional parameter for both set and query forms
Communications
CONN p,b 2 – 15 Connect to Port
SEND p,b [,i] 2 – 15 Send Message to Port
SNDT p,b [,i] 2 – 15 Send Terminated Message to Port
ECHO? b 2 – 16 Echo Message back to Host
BRDC b [,i] 2 – 16 Broadcast Message to Ports
BRDT b [,i] 2 – 16 Broadcast Terminated Message to Ports
GETN? p,i 2 – 16 Get Bytes from Port
RAWN? p,i 2 – 17 Get Raw Bytes from Port
Configuration
NINP? p 2 – 17 Input Bytes Waiting
NOUT? p 2 – 17 Output Bytes Waiting
AINP? p 2 – 18 Input Spaces Available
AOUT? p 2 – 18 Output Spaces Available
DONE? [p] 2 – 18 Transmit Complete
BRER(?) [p,] {i} 2 – 18 Broadcast Enable
RDDR(?) [p,] {i} 2 – 19 Receive Data Disable
RPER(?) [p,] {i} 2 – 19 Receive Pass-Through Enable
MSGL(?) {i} 2 – 19 Maximum MSG Length
TMOT(?) p,{i} 2 – 19 Timeout
TERM(?) p,{z} 2 – 20 Message Termination
CEOI(?) {z} 2 – 20 Generate EOI on hLFi
EOIX(?) {z} 2 – 20 EOI conversion during CONNect
Eavesdropping
VERB(?) [i],{j} 2 – 21 Verbosity
EAVS b 2 – 22 Echo Message to Eavesdrop
EIDN 2 – 22 Identify to Eavesdrop
Serial Configuration
PRTC(?) {z} 2 – 22 Port C Function
PRTD(?) {z} 2 – 23 Port D Function
BAUD(?) p {,i} 2 – 23 Baud Rate
SIM900 Mainframe
2.1 Index of Commands 2 – 3
FLOW(?) p {,z} 2 – 23 Flow Control
PARI(?) p {,z} 2 – 24 Parity
WORD(?) p {,i} 2 – 24 Word Length
SBIT(?) p {,i} 2 – 24 Stop Bits
Status
SSCR? [p] 2 – 25 SIM Status Condition
SSPT(?) [p,] {i} 2 – 25 SIM Status Positive Transition
SSNT(?) [p,] {i} 2 – 25 SIM Status Negative Transition
SSEV? [p] 2 – 25 SIM Status Event
SSEN(?) [p,] {i} 2 – 25 SIM Status Enable
CESR? [p] 2 – 26 Comm Error Status
CESE(?) [p,]{i} 2 – 26 Comm Error Status Enable
TOSR? [p] 2 – 26 Timeout Status
TOSE(?) [p,] {i} 2 – 26 Timeout Status Enable
IOSR? [p] 2 – 26 Input Overflow Status
IOSE(?) [p,] {i} 2 – 27 Input Overflow Status Enable
FCSR? [p] 2 – 27 Flow Control Status
FCSE(?) [p,] {i} 2 – 27 Flow Control Status Enable
CTCR? [p] 2 – 27 CTS Status Condition
CTSR? [p] 2 – 28 CTS Status
CTSE(?) [p,] {i} 2 – 28 CTS Status Enable
PDPR? [p] 2 – 28 Port Data Pending
PDPE(?) [p,] {i} 2 – 28 Port Data Pending Enable
Script
APSS b 2 – 29 Append to Script
ATSS b 2 – 29 Append Terminated to Script
ERSS 2 – 29 Erase Script
LKSS(?) {z} 2 – 29 Lock Script
LISS? 2 – 30 List Script
NBSS? 2 – 30 Bytes Used in Script
AVSS? 2 – 30 Space Available in Script
ENSS? 2 – 30 Script Enable
RNSS 2 – 30 Run Script
Housekeeping
TBIN? 2 – 31 Timebase Input Detect
VTBI? 2 – 31 Timebase Input Analog
PLLC(?) {z} 2 – 32 Timebase Control
CLKD(?) {z} 2 – 32 Clock Distribution
LOCK? 2 – 32 Timebase Status
VLOC? 2 – 33 Timebase Status Analog
VVCO? 2 – 33 Timebase VCO
VMON? 2 – 33 Primary Voltage
SIM900 Mainframe
2 – 4 Remote Programming
IMON? 2 – 33 Primary Current
PMON? 2 – 33 Primary Power
UNDV? 2 – 34 Undervoltage
TICK? 2 – 34 Elapsed Time
DIPS? [i] 2 – 34 DIP Switch
Interface
*RST 2 – 35 Reset
FLOQ 2 – 35 Flush Output Queue
SRST [p] 2 – 35 SIM Reset
FLSI [p] 2 – 36 Flush Port Input Buffers
FLSO [p] 2 – 36 Flush Port Output Queues
FLSH [p] 2 – 36 Flush Port Buffers
*IDN? 2 – 36 Identify
*TST? 2 – 36 Self Test
*CLS 2 – 36 Clear Status
*STB? [i] 2 – 37 Status Byte
*SRE(?) [i,] {j} 2 – 37 Service Request Enable
*ESR? [i] 2 – 37 Standard Event Status
*ESE(?) [i,] {j} 2 – 37 Standard Event Status Enable
*PSC(?) {i} 2 – 37 Power-on Status Clear
*OPC(?) 2 – 38 Operation Complete
*WAI 2 – 38 Wait to Continue
CONS(?) {z} 2 – 38 Console Mode
WAIT i 2 – 38 Wait
REQT(?) {z} 2 – 38 Announce REQT
REQF(?) {z} 2 – 39 Announce REQF
LEXE? 2 – 39 Execution Error
LCME? 2 – 40 Command Error
TOKN(?) {z} 2 – 40 Token Mode
SIM900 Mainframe
2.2 Alphabetic List of Commands 2 – 5
2.2 Alphabetic List of Commands
?
*CLS 2 – 36 Clear Status
*ESE(?) [i,] {j} 2 – 37 Standard Event Status Enable
*ESR? [i] 2 – 37 Standard Event Status
*IDN? 2 – 36 Identify
*OPC(?) 2 – 38 Operation Complete
*PSC(?) {i} 2 – 37 Power-on Status Clear
*RST 2 – 35 Reset
*SRE(?) [i,] {j} 2 – 37 Service Request Enable
*STB? [i] 2 – 37 Status Byte
*TST? 2 – 36 Self Test
*WAI 2 – 38 Wait to Continue
A
AINP? p 2 – 18 Input Spaces Available
AOUT? p 2 – 18 Output Spaces Available
APSS b 2 – 29 Append to Script
ATSS b 2 – 29 Append Terminated to Script
AVSS? 2 – 30 Space Available in Script
B
BAUD(?) p {,i} 2 – 23 Baud Rate
BRDC b [,i] 2 – 16 Broadcast Message to Ports
BRDT b [,i] 2 – 16 Broadcast Terminated Message to Ports
BRER(?) [p,] {i} 2 – 18 Broadcast Enable
C
CEOI(?) {z} 2 – 20 Generate EOI on hLFi
CESE(?) [p,]{i} 2 – 26 Comm Error Status Enable
CESR? [p] 2 – 26 Comm Error Status
CLKD(?) {z} 2 – 32 Clock Distribution
CONN p,b 2 – 15 Connect to Port
CONS(?) {z} 2 – 38 Console Mode
CTCR? [p] 2 – 27 CTS Status Condition
CTSE(?) [p,] {i} 2 – 28 CTS Status Enable
CTSR? [p] 2 – 28 CTS Status
D
DIPS? [i] 2 – 34 DIP Switch
DONE? [p] 2 – 18 Transmit Complete
SIM900 Mainframe
2 – 6 Remote Programming
E
EAVS b 2 – 22 Echo Message to Eavesdrop
ECHO? b 2 – 16 Echo Message back to Host
EIDN 2 – 22 Identify to Eavesdrop
ENSS? 2 – 30 Script Enable
EOIX(?) {z} 2 – 20 EOI conversion during CONNect
ERSS 2 – 29 Erase Script
F
FCSE(?) [p,] {i} 2 – 27 Flow Control Status Enable
FCSR? [p] 2 – 27 Flow Control Status
FLOQ 2 – 35 Flush Output Queue
FLOW(?) p {,z} 2 – 23 Flow Control
FLSH [p] 2 – 36 Flush Port Buffers
FLSI [p] 2 – 36 Flush Port Input Buffers
FLSO [p] 2 – 36 Flush Port Output Queues
G
GETN? p,i 2 – 16 Get Bytes from Port
I
IMON? 2 – 33 Primary Current
IOSE(?) [p,] {i} 2 – 27 Input Overflow Status Enable
IOSR? [p] 2 – 26 Input Overflow Status
L
LCME? 2 – 40 Command Error
LEXE? 2 – 39 Execution Error
LISS? 2 – 30 List Script
LKSS(?) {z} 2 – 29 Lock Script
LOCK? 2 – 32 Timebase Status
M
MSGL(?) {i} 2 – 19 Maximum MSG Length
N
NBSS? 2 – 30 Bytes Used in Script
NINP? p 2 – 17 Input Bytes Waiting
NOUT? p 2 – 17 Output Bytes Waiting
P
PARI(?) p {,z} 2 – 24 Parity
PDPE(?) [p,] {i} 2 – 28 Port Data Pending Enable
SIM900 Mainframe
2.2 Alphabetic List of Commands 2 – 7
PDPR? [p] 2 – 28 Port Data Pending
PLLC(?) {z} 2 – 32 Timebase Control
PMON? 2 – 33 Primary Power
PRTC(?) {z} 2 – 22 Port C Function
PRTD(?) {z} 2 – 23 Port D Function
R
RAWN? p,i 2 – 17 Get Raw Bytes from Port
RDDR(?) [p,] {i} 2 – 19 Receive Data Disable
REQF(?) {z} 2 – 39 Announce REQF
REQT(?) {z} 2 – 38 Announce REQT
RNSS 2 – 30 Run Script
RPER(?) [p,] {i} 2 – 19 Receive Pass-Through Enable
S
SBIT(?) p {,i} 2 – 24 Stop Bits
SEND p,b [,i] 2 – 15 Send Message to Port
SNDT p,b [,i] 2 – 15 Send Terminated Message to Port
SRST [p] 2 – 35 SIM Reset
SSCR? [p] 2 – 25 SIM Status Condition
SSEN(?) [p,] {i} 2 – 25 SIM Status Enable
SSEV? [p] 2 – 25 SIM Status Event
SSNT(?) [p,] {i} 2 – 25 SIM Status Negative Transition
SSPT(?) [p,] {i} 2 – 25 SIM Status Positive Transition
T
TBIN? 2 – 31 Timebase Input Detect
TERM(?) p,{z} 2 – 20 Message Termination
TICK? 2 – 34 Elapsed Time
TMOT(?) p,{i} 2 – 19 Timeout
TOKN(?) {z} 2 – 40 Token Mode
TOSE(?) [p,] {i} 2 – 26 Timeout Status Enable
TOSR? [p] 2 – 26 Timeout Status
U
UNDV? 2 – 34 Undervoltage
V
VERB(?) [i],{j} 2 – 21 Verbosity
VLOC? 2 – 33 Timebase Status Analog
VMON? 2 – 33 Primary Voltage
VTBI? 2 – 31 Timebase Input Analog
VVCO? 2 – 33 Timebase VCO
SIM900 Mainframe
2 – 8 Remote Programming
W
WAIT i 2 – 38 Wait
WORD(?) p {,i} 2 – 24 Word Length
SIM900 Mainframe
2.3 Introduction 2 – 9
2.3 Introduction
The SIM900 Mainframe provides fully buffered multiplexed communications between the host computer and up to 9 SIM modules plus
2 (optionally as many as 4) external RS-232 devices. These SIM/RS232 connections are generically called Ports here, and each port has
a dedicated UART (universal asynchronous receiver & transmitter)
with hardware input and output FIFO buffers. The host computer
(typically a PC) communicates with the mainframe through the host
interface, which can be either RS-232 or (optionally) GPIB. The active
interface is selected with rear-panel DIP switches at power-on.
No protocol requirements are placed on the communications across
the ports—any sequence of bytes can be transmitted to or received
from any port. Simultaneous ongoing communications with multiple ports can be maintained using a packet-message style of com-
mand (see SEND, BRDC, GETN?, RPER commands below). Simple host-to-port communications are provided with the CONN com-
mand.
2.3.1 Device Clear
2.3.2 Queues and buffers
If the host interface is GPIB, the IEEE–488 DCL (Device Clear) or SDC
(Selected Device Clear) interface messages will cause the mainframe
to flush the host input buffer and output queue, and reset the parser
to the idle state.
If the host interface is RS-232, the same action is initiated by theRS-232 hbreaki
RS-232 hbreaki signal (space level (0) for at least one full character
frame). This single “out-of-band” signal allows the host to reset the
mainframe interface to a known state, independent of the current
operating mode.
In particular, a Device Clear event (either from DCL, SDC, or RS232 hbreaki) will cause the mainframe to abandon an active connect
session (see CONN command).
Each port is separately buffered with a port input buffer and port
output queue, while the host interface is buffered with the host input
buffer and host output queue. All queues and buffers are 512 bytes
deep.
Data is initially received from the host interface into the host input
buffer. If the mainframe is not currently in connect mode, then bytes
from the host input buffer are read by the parser until a valid command is found. Command Errors detected by the parser are reported
SIM900 Mainframe
2 – 10 Remote Programming
through the CME flag in the ESR register. Mainframe-directed commands and queries are then handled directly, and responses (if any)
transferred to the host output queue for the host computer to read.
2.4 Port Communications
2.4.1 Message-based communication
Port-directed messages SEND,SNDT and BRDC,BRDT are parsed
for syntax, and then given to the Message Handler for delivery. The
message payload is stripped out of the command, and copied to
the appropriate port output queue(s) for delivery. If the port output queue is full (because the SIM or external RS-232 device has
asserted flow control, or simply because of data rate mismatch), the
mainframe will wait up to TMOT milliseconds until there is suffi-
cient room in the port output queue for the data. In the meantime,
commands and queries from the host will simply accumulate in the
input buffer until that fills as well. At that point, flow control on
the host interface should hold off any further transmissions from the
host until the buffers clear up.
Data received from the ports is initially stored in the corresponding
port input buffer. If the corresponding bit in the ReceivePass-through
Enable Register (RPER) is set and there is sufficient room in the
host output queue, then the data is wrapped into a MSG unit and
transferred to the output queue for delivery to the host. If the output
queue was too full, the message will be sent as soon as sufficient
space becomes available. If the corresponding bit in RPER is clear,
then the corresponding bit in the Port Data Pending Register (PDPR)
is set.
2.4.2 Connection-based communication
If the mainframe is connected to a port via the CONN command, the
situation is somewhat different. Bytes received from the host accumulate in the input buffer, where they are scanned for matching the
escape string provided with CONN. Non-matching bytes are directly
transferred to the port output queue. A partial match is held off
until an unambiguous complete match or non-match is present. On
a successful complete match, the connect mode is terminated and the
mainframe is ready for new commands.
Concurrently, bytes received in the port input buffer are transferred
directly to the host output queue. Data received at the unconnected
ports will be held in their port input buffers (causing the corresponding bit(s) in the PDPR to be set).
SIM900 Mainframe
2.4 Port Communications 2 – 11
2.4.3 Port map
The SIM900 Mainframe ports are defined in the following table:
Port Type Description
1 SIM Slot 1 SIM port
2 SIM Slot 2 SIM port
3 SIM Slot 3 SIM port
4 SIM Slot 4 SIM port
5 SIM Slot 5 SIM port
6 SIM Slot 6 SIM port
7 SIM Slot 7 SIM port
8 SIM Slot 8 SIM port
9 SIM Remote SIM port (DB-15-F back panel connector)
A RS-232 Aux–1 DTE (DB–9/M back panel connector)
B RS-232 Aux–2 DTE (DB–9/M back panel connector)
C RS-232 Eavesdrop DCE (DB–9/F back panel connector)
D RS-232 COMM DCE (DB–9/F back panel connector)
Ports 1 through B are always available as user ports, with A & B
as generic RS-232 ports. After power-on, ports 1–B default to 9600
baud, 8-bits, no parity, and 1 stop bit.
Port C (Eavesdrop) is normally dedicated to monitoring communications between the mainframe and host, but can be remapped as
an additional general purpose port with the PRTC command. At
power-on, this port defaults to 9600/8/N/1. Baud rate, parity, word
size, and stop bits can be reconfigured by command after poweron, regardless of whether Port C is used for eavesdrop or general
communications.
Port D (COMM) is normally dedicated as the RS-232 interface to
the host computer. At power-on, this port defaults to the baud rate
selected by the rear-panel DIP switches, or 9600 if the DIP settings are
invalid (8/N/1). If RS-232 is NOT the active host interface, then Port D
is normally inactive, but can be remapped as an additional general
purpose port with the PRTD command. Baud rate, parity, word
size, and stop bits can be reconfigured by command after power-on,
regardless of whether Port D is used for the host interface or general
communications.
When Port C or D are not reconfigured for general port communications, the corresponding PC and/or PD bits in the RPER, BER, and
PDPR registers are undefined; they can be written or read, but will
have no effect.
SIM900 Mainframe
2 – 12 Remote Programming
2.5 Commands
All commands for the SIM900 Mainframe originate at the host computer1, and are sent to the mainframe via the host interface. The
commands are organized according to functional groups, beginning
with commands that directly control communications with the SIM
modules. Other groups of commands configure the mainframe communications hardware, status reporting mechanism, startup script,
internal housekeeping, and host interface.
2.5.1 Command syntax
All command names are 4-characters long and are case-insensitive.
IEEE–488.2 defined commands begin with the “*” character followed
by 3 letters, while SIM900-specific commands are composed of 4
letters.
The four letter mnemonic (shown in CAPS) in each command se-
quence specifies the command. The rest of the sequence consists of
parameters.
Commands may take either set or query form, depending on whether
the “?” character follows the mnemonic. Set only commands are
listed without the “?”, query only commands show the “?” after the
mnemonic, and optionally query commands are marked with a “(?)”.
Parameters shown in { } and [ ] are not always required. Parameters in
{ } are required to set a value, and are omitted for queries. Parameters
in [ ] are optional in both set and query commands. Parameters listed
without any surrounding characters are always required.
Do not send ( ) or { } or [ ] as part of the command.
The command buffer is limited to 255 bytes, with multi-byte block parameter bytes separately stored in an independent 255 byte buffer—
any command that exceeds this size will generate a command error
and be discarded.
If the host interface is RS-232, commands are terminated by either
hCRi (ASCII 13) or hLFi (ASCII 10) characters that are outside any
protected binary block or string. If the host interface is GPIB, then
commands are terminated by either hLFi or hEOIi or hLF-EOIi. Execution of the command does not begin until the command terminator
is received.
Unlike most SIM modules, nomulti-command messages(i.e., “;” separated
commands) are allowed for the SIM900.
1
or from the startup script
SIM900 Mainframe
2.5 Commands 2 – 13
The following table summarizes the notation used in the command
descriptions:
symbol definition
p Port number (1–9, a–d, A–D, but see below)
i,j Integers
z Literal token
b Multi-byte (string) block
(?) Required for queries; illegal for set commands
var parameter always required
{var} required parameter for set commands; illegal for queries
[var] optional parameter for both set and query forms
2.5.1.1 Ports
Port parameters can be given as either simple decimal integers, or a
single-letter hexadecimal value (without any leading 0x).
Many of the commands to set/query a register accept an optional
port parameter. In these cases, if the optional parameter p is given,
then the command only sets/queries the single bit corresponding to
the binary weight 2p. Typically, this bit represents Port p, but in a
few cases additional flag bits are packed into the register. For these
additional flag bits, the optional p still restricts the command to the
single bit, but it no longer corresponds to a port. Thus, it is possible
in these cases for p to be E, despite the maximum port value of D.
2.5.1.2 Integers
2.5.1.3 Tokens
SIM900 Mainframe
Integer parameters follow “C-language” style. Simple decimal integers are indicated by beginning with a non-zero digit (1–9). Octal
integers are represented with a leading zero digit (0). Hexadecimal
integers are given by a leading 0x or 0X.
For example, 26, 032, 0x1A all refer to the integer value 26.
Tokens are listed here as word–integer pairs, such as AUTO 2. For
set commands, token parameters must either be the exact text word
indicated (case-insensitive), or the corresponding decimal integer
code. For example, to set the response termination sequence to
hCRi+hLFi, the following two commands are equivalent:
TERM CRLF —or— TERM 3
2 – 14 Remote Programming
For queries that return token values, the return format (keyword or
integer) is specified with the TOKN command.
2.5.1.4 Blocks
Multi-byte block parameters can follow one of 3 formats (4 on GPIB).
Quote-delimited strings : An arbitrary byte sequence bounded by either " or ’ charac-
ters. All characters (including control characters) are allowed.
The quoting character itself (either " or ’) can be included by
escaping with an additional quote. For example,
"It is a ""good"" quote"
is identical to
’It is a "good" quote’.
Hex-formatted binary : #Hxx xx xx, where xx are hexadecimal bytes (00 through ff).
Whitespace is ignored.
Definite-length arb. : #abbbrrrr, where a is a single non-zero digit equal to the digit
count in bbb, bbb is a decimal integer count of the number of
data bytes to follow, and rrrr are the raw data bytes.
Indefinite-length arb. : #0rrrrhLF-EOIi, where rrrr is the raw data block, and
2.5.2 Examples
hLF-EOIi is the newline character (ASCII 10) with the GPIB-EOI
line simultaneously asserted. (only on GPIB)
Each command is provided with a simple example illustrating its
usage. In these examples, all data sent by the host computer to
the SIM900 are set as straight teletype font, while responses
received the host computer from the SIM900 are set as slanted
teletype font. Command terminators explicitly sent by the host
computer are set with the symbol “”.
The usage examples vary with respect to set/query, optional parameters, and block parameter formats. These examples are not exhaustive, but are intended to provide a convenient starting point for user
programming.
SIM900 Mainframe
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