- on Home & Garden
- Published in issue 9/2007 on page 0
Four-channel logic analyser
The best way to inspect digital signals is with a logic analyser. Sometimes it's useful to be able to do this on-site, or you may have to take a ‘floating’ measurement. The four-channel logic analyser described here is suitable in both situations due to its compactness and because it can be battery powered. The maximum sampling rate is 2 MHz and the circuit has sufficient memory to store 1024 samples of the signal. The dot-matrix display with a resolution of 64 by 128 pixels shows a clear representation of the digital signals.
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- PIC18F4580-I/P, programmed
- Construction kit including the PCB, controller, display, case and all parts
- PCB, bare
CAM/CAD data for the PCB referred to in this article is available as a Gerber file. Elektor Members can exclusively download these files for free as part of their Membership. Gerber files allow a PCB to be produced on an appropriate device available locally, or through an online PCB manufacturing service. Elektor recommends its business partner Eurocircuits as the company of choice for its own prototypes and volume production in selected cases.
The circuit diagram erroneously shows X1 as a 20 MHz crystal. This should be 10 MHz as stated in the parts list.
R1 = 680Ω
R2,R11-R16 = 10 k
R3-R6 = 330Ω
R7-R10 = 100k
R17 = 56Ω
R19 = 1k
R20 = 47Ω
R21 = 220Ω
P1 = 20kΩ preset, multiturn, vertical mounting
C1,C2 = 22pF
C3-C6 = 100nF
D1-D10 = 1N4148
D11 = 1N4001
D12 = LED, 5mm diam.
T1,T2 = BC337
IC1 = 74HC04
IC2 = PIC18F4580-I/P, programmed, Elektor SHOP # 060092-41
IC3 = 7805
Bz1 = AC buzzer
X1 = 10MHz quartz crystal
Graphic LC display, 128 x 64 pixels, e.g. DEM128064A or NLC128x64 (Conrad Electronics # 187429)
Case 186 x 123 x 41mm with compartment for 9V battery, e.g. Strapubox (Conrad Electronics # 522775)
S1-S5 = pushbutton Multimec RA3FTL6 w. knob AQC09-24.2
S6 = on/off switch
9-V battery clip
5 wander sockets, screw mount (for connection to I1-I5)
Kit of parts incl. case: Elektor SHOP # 060092-71
PCB layout: free download from www.elektor.com, file # 060092-1