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Last month, we introduced the Digital Logic Analyser & gave the circuit details. This month, we describe the construc­tion & the software installation. Windows-based digital logic analyser; Pt.2 By JUSSI JUMPPANEN Despite the apparent circuit complexity, this project is very easy to build. All the circuitry is contained on the two double-sided PC boards and these feature plated-through holes, component overlays and solder masks. The main thing to watch out for is that all parts are correctly installed the first time. Once you have soldered a part into a plated-through board, it is quite difficult to remove. 60  Silicon Chip The easier of the two boards is the internal XT bus card which uses just five ICs plus a few other parts. None of these ICs require sockets so the first step in the construction is to solder them all in place. Make sure that each IC is correctly positioned and that it is aligned as shown in the overlay diagram – see Fig.7. Once the ICs have been soldered into place, the 8-bit DIP switch, resis- tors and decoupling capacitors can be added. Final­ly, the female DB37 connector can be soldered into place and the slot bracket attached to the card – see photo in Pt.1. Make sure that the DB37 connector used is a female type and that it is a long version so that it protrudes the correct amount beyond the end of the board. If a short DB37 connector is used, the socket will not be flush with 1 1 0.1 U1 74LS688 U4 74LS245 J2 DB37/F A8 A9 A10 A11 A12 A13 A14 A15 ON S1 SW-DIP8 0.1 0.1 U3 74LS04 0.1 Logic analyser board 1 U5 74LS244 0.1 The external logic analyser card is a little more compli­cated to build as it uses some 29 ICs in total. The first step is to install IC sockets for IC1, IC2, IC10, IC13 & IC22 – see Fig.9. Do not use sockets for the remaining ICs however, as they will only add to the expense of the project. Once the sockets have been installed, the remaining ICs can be installed by soldering them directly to the PC board. As before, take care to ensure that each IC is placed in its correct location and is oriented correctly. This done, the remaining components can be installed. These include the resistors, capaci­tors and crystal. A 16-pin IDC socket will also have to be sol­dered into the IDC16 location. A point to note here is that although the PLL (IC13) is a 74HC4046, not all 74HC4046s are the same. A Philips device will be supplied with the kit but a National Semiconductor device can also be made to work simply by changing a few component values – see Table 4. At this point, the DB37 expansion port connectors can be added. A male connector is used for the input socket, while a female connector is used as the output socket. The final stage in the construction involves the wiring of the channel inputs and the external clock. The channel inputs are very simple to wire because IDC connectors are used. The external clock wiring (to the input socket and switch) is slightly more difficult because each lead has to be soldered independently, but fortunately there are only six connections to make. The external board can now be mounted in the instrument case. To do this, the front and rear panels need to be drilled to match the supplied templates. The rear panel is then fastened to the DB37 connectors, while the DB15 channel input connector, external clock input RCA jack and internal/external clock switch are attached to the front panel. All that remains now is to wire the nine probe clips (eight input channels plus ground) to the matching DB15 plug connector. Be sure to connect each input to the pin number des- 1 1 U2 74LS02 1k 1k 1k 1k 1k 1k 1k 1k the PC case when the card is installed in the bus slot. J1 IBM XT BUS Fig.7: parts layout for the internal bus card. DIP switch S1 (top, left) is used to partially set the hardware address. Fig.8: the hardware address entered in the software must match the address set by the DIP switch­es on the internal & external cards – just click Edit/Hardware to bring up the above display. The default is 0F30; change this only if necessary. ignated on the circuit diagram and use a black probe clip for the ground connec­tion. Hardware installation The first step in the installation is to set the DIP switches on the two PC boards to match the required I/O address. During testing, the I/O location 0F30 was used successfully on a machine with two serial ports, a printer port, a games port and a fax card. It is recommended that this location be used for your initial tests. Table 5 shows the DIP switch settings on the two boards for various I/O addresses. Note that, because of the inverting nature of the circuit, a logic 0 is set by turning the DIP switch on, while a logic 1 is set by turning the DIP switch off. Thus, to set an address of 0F30, turn DIP switches A15-A12 ON and A11-A8 OFF on the internal card; and July 1993  61 OUTPUT INPUT 1 1 IC8 74LS193 IC9 74LS193 IC19 74LS193 33pF IC7 74LS193 1 0.1 0.1 0.1 0.1 0.1 0.1 XTAL 33k 1 IC18 74LS125 0.1 1 1 0.1 1k GND IC12 74LS74 IC20 74LS193 1 0.1 0.1 EXT CLOCK 120  0.1 U103 74LS245 0.1 U104 74LS245 0.1 1 IC13 74HC4046 1 U102 74LS138 1k U101 74LS138 1k 1 U100 74LS85 A4 A5 A6 A7 ON 1 1 IC15 74LS04 1 1k 470  1k S100 SW-DIP4 470  1 0.1 S1 4.7uF 1 IC17 74LS374 IC4 74LS374 IC16 74LS374 IC11 74LS245 IC10 6116 0.1 0.1 0.1 0.1 0.1 1 1 IC22 74HC4040 1 IC24 74LS08 1 IC14 74LS32 0.1 1 0.1 IC23 74LS08 IC6 74LS85 0.1 0.1 IC5 74LS08 IC21 74LS193 1 1 0.1 0.1 0.1 0.1 0.1 Fig.9: parts layout for the external PC board. Install IC sockets for IC1, IC2, IC10, IC13 & IC22 but not for the other ICs. A male DB-37 connector is used for the input socket, while a female connector is used for the output socket. turn A7-A6 ON and A5-A4 OFF on the external card. The remaining address locations (A3-A0) are fixed – see Table 5. The internal card can be inserted into any spare XT or AT bus slot (make sure that the power is off). At this point, the computer can be powered up and checked to ensure that it boots as normal. If the machine starts but locks up, the card is probably using an I/O location required by another device. If so, turn the machine off, change the I/O address to another location (eg, to 1030, 0E30 or 0D30) and try again. IC2 74LS14 1 1 SENSORS IDC16 1 1 IC1 74LS14 1 1 IC3 74LS374 1 0.1 into a directory called dla (you have the option of changing this to another name) and create the relevant program group. After that, the program can be run by double clicking TABLE 4 Software installation An installation program on the disc supplied with the kit makes this job a breeze. This program must be run from within Windows. To install the software, insert the disc into drive A:, then choose the FILE RUN menu option and type A:\ install. This will install the software IC13 Philips 74HC/ GCT4046 NS 74HC4046 C200 2200pF 33pF C201 0.47µF 4.7µF R200 10kW 1kW R202 100W 120W R203 10kW 33kW Table 2 Address Internal XT Card External Card Fixed A15 A14 A13 A12 A11 A10 A9 A8 A7 A6 A5 A4 A3 A2 A1 A0 1030H 0 0 0 1 0 0 0 0 0 0 1 1 0 x x x 0F30H 0 0 0 0 1 1 1 1 0 0 1 1 0 x x x 0E30H 0 0 0 0 1 1 1 0 0 0 1 1 0 x x x 0D30H 0 0 0 0 1 1 0 1 0 0 1 1 0 x x x Note 1: 0 = DIP Switch ON; 1 = DIP Switch OFF due to the inverting nature of the circuitry. Note 2: an "x" means software controlled addressing. 62  Silicon Chip Above: the IDC socket on the external board is wired to a DB15/F connector on the front panel via a ribbon cable. The front panel also carries the DPDT clock source switch & an RCA socket for the external clock input. on the Digital Logic Analyser icon. With the software running, click the Edit/Hardware menu option to set the hardware address to match the address previously set by the DIP switch­es (the default is 0F30; change this only if necessary). The hardware addressing can then be easily checked by toggling the external/internal clock switch on the front panel. As the switch is toggled, the clock status field at the bottom right of the screen should also toggle to match the switch setting. If the status does not change, this probably means that the actual hardware address does not match the software hardware address. If this fails to fix the problem, check the switch wiring. The voltage on pin 9 of IC18 should change from 0V to 5V as the switch is toggled. If no voltage change is observed it means The nine probe clips (eight input channels plus ground) are wired to a DB15 plug connector that matches the socket on the front panel. Be sure to connect each input to the pin number designated on the circuit diagram. that the switch is wired incorrectly. If the voltage changes but is not registered by the software, the address must be wrong. When the internal/external clock is correctly registered by the software, the system is correctly configured and the setting will not need to be changed again. The project can now be tested for correct operation by first connecting the various channel probes to any suitable TTL clock circuit (don’t forget to connect the ground probe). Fig.12 shows a suitable test circuit. July 1993  63 Where to buy the kit Fig.10: the frequency & period of a waveform can be measured by clicking the right mouse button at the start of a cycle & by holding down the SHIFT key & clicking the right mouse button at the end of the cycle. Fig.11: the Search Level Selection dialog box lets you search for particular data samples & trigger levels. A channel can be marked high, low or don’t care. All individual channel search criteria must be met for the search to succeed. The next step is to program the triggering options and the sample frequency. To program the triggering options, simply select the Edit/Trigger menu to bring up the Trigger Selection menu (or double click the left mouse button in the display area). The sample frequency can be set anywhere between 100kHz and 6MHz (in 100kHz steps) by clicking on the UP & DOWN buttons located towards the bottom left of the display. After that, it’s simply a matter of clicking on the Start button. If the sample is not completed within one second, click on the Abort button, reprogram the trigger value and try again. If all is OK, the screen should 64  Silicon Chip +5V 16 7 5 11 27k 2.7k 4 6 10 IC1 4060 14 33pF 13 9 15 CLOCK FREQUENCY 200kHz 1 12 Q4 Q5 Q6 Q7 Q8 Q9 Q10 Q12 8 Fig.12: this simple test circuit generates eight spot frequencies ranging from 12.5kHz to 48.8kHz. The kit is offered in three formats: (1). A complete kit consisting of all the parts as listed – price $215.00 plus $10.00 p&p. (2). A complete kit of all parts except for the case – price $185.00 plus $5.00 p&p. (3). Two double-sided PC boards (with screened overlays) plus software – price $90.00 plus $5.00 p&p. To order, send cheque or money order to Jussi Jumppanen, PO Box 697, Lane Cove 2066, NSW. Phone (02) 428 3927. Please specify whether a 5¼-inch or 3½-inch disc is required. Note: copyright of the two PC boards for this project is retained by the author. refresh and the results of the sample will be displayed. A context-sensitive help system is provided and this can be accessed at any time by clicking on the Help menu option. For example, if the Help button is clicked in the Trigger selection menu, an explanation of the Edit Trigger Command will be given. Once you have sample waveforms displayed, you can try out some of the other features of the software. For example, you can examine the effects of changing the trigger selections and the timebase option. The software also lets you search for particular data samples and trigger levels. And if you don’t like the dis­play colours or the line thickness, you can edit these to suit your requirements. You can also make accurate frequency and period measurements on individual waveforms. To do this, place the cursor at the beginning of a waveform cycle and click the right mouse button, then move the cursor to the end of the cycle and click the right mouse button while holding down the SHIFT key. The frequency and period of the waveform can now be read from the data bar. Finally, readers should note that the 4MHz crystal was left off the main circuit diagram (Fig.4). This crystal goes between pin 13 of IC15f & pin 10 of IC15e. Several pin numbers were also left off: the input of IC15d is pin 9; the input of IC15e is pin 11; and the input SC of IC15f is pin 13.