ComScope User & Programming Manual
Contents
1. IN 1 8 19 aa 69 Ga 119 ida tea 9a 310 aaa Ciose Apph Charges Riamh Triggir Jg Fal ComScope window 3 control areas ComScope Trace Settings Trite Sitting Trace Signal Representation Sampling Click Decimation gible Plot eta Color Empdet f 1 Lunes W The Trace Settings section provides user control over the following trace attributes Trace select trace 1 2 3 or 4 to be configured Signal each trace can capture one of several multiplexed signals Select the multiplexer source Representation enter the precision for the selected signal Ranges from 1 bit binary to 16 bits Also indicates whether the binary representation is unsigned or signed 2 s complement Sampling clock select between nominal sampling clock as described in the specifications and the FPGA processing clock fex For example in a digital modulator waveform signals are typically 2 sampled at 4 samples per symbol their nominal sampling rate whereas binary data streams may be typically sampled at 1 sample per bit their nominal sampling rate When comparing different traces it is often clearer to select a common clock i e the FPGA processing clock fex as it ensures the same time scale Decimation select the sampling clock decimation The main purpose of decimation is to stretch the time scale for example when a signal bandwidth is much smaller than the sampling clock frequency Decim2. be exported out of the ComBlock by reading at address 250 Stored data is read in sequence starting at the initial address defined in REG237 238 239 and subsequently autoincremented after byte read at address 250 REG250 0 capture ceased Progress at least one trace is capturing REG251 bit 0 Trigger 0 trigger not found Found 1 trigger found This bit is cleared set to 0 upon resuming capture see Read Write register 250 bit 2 REG251 bit 1 Capture in Start Capture This bit toggles every time capture is Toggle resumed see Read Write register 250 bit 2 REG251 bit 2 This bit toggles every the trigger is re armed see Read Write register 250 bit 1 REG251 bit 3 Trigger Re arm Toggle The general M amp C commands Set Register SRG and Set Register Temporary SRT are used to send commands to the ComBlock registers See reference document ComBlock Monitoring amp Control Reference www comblock com download M amp C_reference pd f FPGA VHDL Development Platforms The ComBlock family of rapid prototyping modules includes several FPGA V HDL development platforms COM 1000 COM 1100 COM 1200 COM 1300 COM 1400 COM 8000 based on Xilinx FPGAs VHDL code templates for these development platforms are being updated with basic ComScope source code Template source code can be downloaded from www comblock com download com1000_002 zip
3. 1 4 Kbit Memory Sample clock 1_ Sine 12 Sample clock 1_2 gt To Trace display Sine al1_3 Sample clock 1 3 gt Signal 1_n Sample clock 1_n one shot trigger ne 2 1 Sample clock 2_1 Trace 2 4 Kbit Memory Signal 2 2 Sample clock 27 Pos Signal 2 3 To Trace2 Sample cloak 2 3 7 2 83 Sa display Signal 2_m Sample clock 2_m one shot nal T 1 trigger TE ee ockT 1 _ ts alT 2 Sample clock T 2 gt Sample KTS ie Signal T_x Sample clock T_x ComScope Functional Block Diagram 2 traces MSS 18221 Flower Hill Way A Gaithersburg Maryland 20879 U S A Telephone 240 631 1111 Facsimile 240 631 1676 www ComBlock com MSS 2000 2005 Issued 8 11 2005 Graphical User Interface User Manual First Step The very first step in using ComScope is to consult the ComBlock specifications for definitions regarding the trace signals and trigger signals For example the COM 1028 FSK MSK GFSK GMSK modulator specifications include the following trace and trigger signals definitions Nominal sampling rate before Gaussian signed symbol filter after Gaussian signed symbol filter 3 Frequency 8 bit 8 samples 512 modulator phase signed symbol Trace 1 signals 4 Modulated 8 bit fak Signal I channel signed 80 MHz Trace 2 signals Format Nominal Capture sampling length rate samples 1 Internal PRBS Binar
4. Com Block MANUAL Overview New FPGA based digital ComBlock modules are equipped with the ComScope data capture capability to help users visualize otherwise hidden digital signals These modules are identified with Internal digital signals whether binary or digital representation of analog signals can be stored in real time within the internal memory then exported to a host computer for plotting storage and further processing The data of interest is captured at speeds up to the FPGA processing speed The user can select lower sampling rates to expand capture over a longer time period Internal triggers or user manual trigger can be selected Once the memory is full data capture stops until re armed by the user Up to four data sources Trace 1 Trace 2 Trace 3 and Trace 4 can be captured simultaneously Depending on the source type the data storage is organized as 4096 binary bits 512 8 bit samples or 256 16 bit samples Refer to specific ComBlock module specifications for the definition of signals triggers and formats Most ComScope settings are stored in volatile memory They are loaded automatically by the ComBlock at power up or reset Several ComScope windows each pertaining to a distinct ComBlock can be opened at the same time However it should be noted that in most cases triggers cannot be synchronized across multiple ComBlocks COMSCOPE USER amp PROGRAMMING nal 1 agna Trace
5. ation can be selected by steps of 2 from 1 1 no decimation to 1 2 1 2 147 483 648 One should be aware that capture duration increases as decimation factors increase All above controls are stored in non volatile memory within the ComBlock module They are recalled at power up User changes are enacted by pressing the Apply Changes button in the lower part of the ComScope window The changes are applied the next time data is captured i e after pressing the Re arm Trigger button Visible this checkbox allows one to display one trace at a time or all together The captured data remains in memory while the trace is not visible The selection is volatile i e returns to the default value at power on Plot style select between small dots big dots lines and big dots and lines The selection is volatile 1 e returns to the default value at power on Color select the trace color from the palette The selection is volatile 1 e returns to the default value at power on Export export the trace samples to a decimal format text file for further processing using other applications for example MS Excel open or DatalGet external datal import text file or Matlab load command ComScope Trigger Settings Trigger Settings Signal Representation Threshold Edge Position fi fi pitunsigned 1 Rising 50 The Trigger Settings section provides user control over the following trigger related at
6. igger re arm Capture resume 0 trigger set at 0 1 trigger set at 10 2 trigger set at 50 3 trigger set at 90 Note All trigger positions must be identical Use same value for all traces Non volatile storage n l REG241 bits 7 5 A REG243 bits 7 5 n 3 REG245 bits 7 5 n 4 REG247 bits 7 5 0 trigger is off 1 63 internal signal selection ComBlock specific definition See specifications Non volatile storage REG248 bits 5 0 0 trigger threshold is unsigned 1 trigger threshold is signed Non volatile storage REG248 bits 6 0 falling edge rising edge Non volatile storage REG248 bit 7 When the selected trigger signal is an m bit word then the trigger threshold is given by REG249 bit 0 REG 249 bits 1 0 REG249 bits 3 0 REG249 4 x REG249 256 x REG249 One shot trigger originated by the user Write a 1 once to force the manual trigger Overrules the trigger signal selection The trigger must have been re armed before a force trigger may take place Volatile REG250 bit 0 One shot command originated by the user Writing a 1 once will force the traces in use to switch state from Capture in progress pre trigger to Capture in progress waiting for trigger Volatile REG250 bit 1 One shot command originated by the user Writing a 1 once starts the capturing again after a capture was completed REG250 bit 2 Monitoring Definition Read data ComScope trace data can
7. lly set when the Auto scale checkbox is on Otherwise users can specify the display scale by entering the Xiin Xmax Y min and Ymax Values then by clicking on the Rescale button The time axis X axis is relative to the trigger negative values represent samples captured before the trigger condition occurred and vice versa The time axis is expressed in number of samples since the trigger units All above controls are stored in non volatile memory within the ComBlock module They are recalled at power up ComScope Operations Close Apply Changes Rie arm Trigger The key difference between a conventional oscilloscope and ComScope is that ComScope capture and display is always started manually There is no automatic refresh Forte Trigger Re arm Trigger orders the ComBlock to capture a new batch of samples If the capture is complete within approximately one second the captured data is automatically displayed If capture is incomplete or if the trigger condition did not yet occur the user is invited to press either the Force Trigger button if trigger did not occur and or the Plot button 1f the capture is too slow Force Trigger manual substitute to the automatic trigger condition Must be used when the trigger is disabled Plot ask the ComBlock to provide the captured data Keep pressing this button until the capture is complete Programming Interface This section is intended fo
8. r designers who want to design their own graphical user interface It can be skipped by ComBlock Control Center users All ComScope related commands are register mapped within the ComBlock Registers 237 through 251 are reserved to this effect All registers are 8 bit wide Register mapping is as follows Trace n signal 0 disable trace n selection 1 127 signal selection ComBlock specific definition See specifications Non volatile storage n 1 REG240 bits 6 0 n 2 REG24 2 bits 6 0 HSI REG244 bits 6 0 n 4 REG246 bits 6 0 Trace n 0 use nominal sampling clock as sampling clock described in the specific ComBlock selection specifications 1 use the ComBlock fy processing clock typically 40MHz or 80 MHz or 120 MHz as sampling clock This allows to compare multiple signals on the same time scale In either case the sampling clock can be further decimated to stretch the time scale see decimation control below n l REG240 bit 7 a2 REG242 bit 7 REG 244 bit 7 n 4 REG 246 bit 7 Trace n Decimate selected signal sampling clock sampling clock by 2 where n 0 through 31 decimation 0 means no decimation Non volatile storage n l REG241 bits 4 0 n 2 REG243 bits 4 0 o REG245 bits 4 0 n 4 REG247 bits 4 0 Trigger position with respect to trace n capture window Trigger signal selection Signed Unsigned trigger threshold Trigger edge Trigger threshold Force trigger Tr
9. tributes Signal the trigger signal can be selected among several signals through a multiplexer Alternatively the trigger function can be disabled Representation enter the precision for the selected trigger signal Ranges from 1 bit binary to 16 bits Also indicates whether the binary representation is unsigned or signed 2 s complement Threshold enter the trigger threshold level Edge enter the trigger edge slope rising or falling Position the trigger position determines how much data is captured before a valid trigger condition occurs A vertical line at 0 10 50 or 90 of the displayed time identifies the trigger time 2256 J W Agi A56 131 106 1 56 J1 fi ia dd fa oa ita ddd 169 194 Fis yaa 7 r Trigge E M N Positi i i M m ii ii oy ry a ia ka i fy _ som AN ws KS Fi E Samples atte Trigger a a ii BETAL Samp P H riogan i620 08 A 1 8 131 108 lp a1 b a as 6g oa TiS ida 103 194 JiS H4 All above controls are stored in non volatile memory within the ComBlock module They are recalled at power up User changes are enacted by pressing the Apply Changes button in the lower part of the ComScope window The changes are applied the next time data is captured 1 e after pressing the Re arm Trigger button ComScope Plot Settings Plot Settings Autoscale Min Wax Y Min Y Wax Rescale W f The display scale is automatica
10. y Il sample 4096 11 test sequence bit 2 Modulated 8 bit fak Signal Q channel signed 80 MHz Format 1 Start of internal PRBS11 test sequence Example of Trace Trigger signals definition COM 1028 In this example trace 1 can capture and display one of four possible signals all in 8 bit signed format 512 samples of each signal are captured each time Likewise trace 2 can capture one of two signals either 4096 samples of 1 bit binary data or 512 samples of 8 bit signed samples Only one trigger signal is offered Starting ComScope Start the ComBlock Control Center enumerate the ComBlocks highlight the desired ComBlock and click on the icon as shown below ComBlock Control Center Fie Operations Functions Help i Show ComScope window for the selected ComBlock coms indow for th lected ComBlock FSK GFSIMMSirSiron wiuuuictl i Starting ComScope ComScope window The ComScope window is organized into three distinct control sections a Trace settings on top b Plot settings on the lower left c Trigger settings on the lower right ComS cope FORAGE SEAS ESSE Hikaia Decimation Waihle Flot etia C Erir 2H EE ZR 191 156 131 108 BT 5E EL 19 ae bu a4 119 144 183 14 M9 M4 i sr om a rn Wf A ir aa nS a th as a o i er ee ee i 3 i a a M H A k Mi as Wa i ad 7 7 of he za Tish J b aI al J Le i ra nd J Le 113 he
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