Showing posts with label PC-Interface. Show all posts
Showing posts with label PC-Interface. Show all posts

Tuesday, October 11, 2016

Isolated RS-232 Serial Port Interface to SBC

Subject: Help! - Date: Thursday, December 16, 2010, 4:40 PM
Hello delabs
I have question about one your project . The question is about the project RS232 with Opto-Isolation on I need this very much . Do i need to use max 232 or something else on uC side , or i connect directly on uc rxd/txd pins .I need this answer so much , im new in this . please help

Best Regards
Mail from SS (CC) - Russia

This was done when MAX232 was not invented yet. This interfaces with PC well. If you want to make a PC based datalogger with 80C31, then this gives a safe PC to 80C51 SBC Serial Link.

Suppose a Temperature sensor or a Heater Open up. If the High Voltage reaches the A/D and SBC. The PC will be next Victim.

The Affordability and Product Safety Aspects, Including Fire Hazards; made me use this, as any other solution would make product expensive. An Opto-coupler and well designed PCB can give more than 2 KV isolation.

The MAX232 does not have isolation, but look here Isolated RS-232 Transceivers. The MAX232 also generates a Higher Voltage level, like 10V for proper RS232.


The MAX3250 is a 3.0V to 5.5V powered, ±50V isolated EIA/TIA-232 and V.28/V.24 communications interface with high data-rate capabilities.

The circuit i have made is very old and you can interface any serial uC with PC. No other chip is needed. It is cumbersome to build it and get it working for many. I suggest use one of these chips from Maxim unless you want to Adventure like me.


Sunday, July 10, 2016

Logic Analyzer on Computer

Title: Test circuit for Logic Analyzer - Message: I am a retired hobbyist. Source files needed.The following was submitted on March 8th, 2008 at 06:47AM (CST). Subject: delabs Schematic Source Request.  Circuit: del20006.pdf .
Mail from JL USA

Sorry for the late reply, Can you explain in detail your doubt or problem. Meanwhile Have a look at
these circuits

40MHz 32 Channel Logic Analyser It is a 32 Channel, 40Mhz, fully PC controlled TTL/CMOS logic analyser with internal/external triggering and trigger delay. Internal triggering is fully maskable (High/Low/Don't Care) on all 32 channels.

FPGA Based Logic Analyzer The project includes the actual analyzer in VHDL (for Spartan 3 FPGA) and a PC Software for the end user. The design employs a FPGA board that can be obtained easily.

Logic Analyzer on Computer

MiniLA - logic analyzer SW & HW.
MiniLA is a project of simple and cheap logic analyzer designed for amateur and semi-professional work.


I am interested in obtaining a copy of the file "" referred to in the article. PC-Based Logic Analyzer (below). The link to the file is not available. The file contains the software for the circuit described.

Reply from JL

Monday, November 10, 2014

Isolated Full-duplex Serial Interface

I would like to build Optoisolated RS232 interface. I've googled a little bit, and I came across your design:

RS232 with Opto-Isolation

However presented schematic is of poor quality - I'm not able to read all parts numbers and their values. Is it possible for you to send me a copy of this schematic, which is more readible?

Mail from M from Poland

You had written to me a few months back, I suggest this circuit

Isolated Full-duplex Rs232 Interface

This self powered interface circuit electrically isolates the TxD and RxD lines from the PC serial port and protect the PC from direct connection to hazardous voltages.

See also Isloated Interface to Microcontroller

See a Commercial Solution you can buy

CVT-232A-3 port-powered 3-wire RS232 Isolator

CVT-232A-3 port-powered 3-wire RS232 Isolator

"The unit features 5000V opto-isolation circuitry and optically isolates three (3) RS-232 lines (TX, RX and GND), which effectively protects your RS-232 devices from ground loops, noise problems, transient surges, remote lightning and spikes."

Thursday, June 19, 2014

Electronics Work Bench

How can I get a software for an electronics work bench for my pc.

mail from EA

I did not understand about the 'electronics work bench' pc based instruments are made by National Instruments see links in my electronics orange pages. try to look with Picotech and Atcweb for low cost solutions.


TINA is a powerful yet affordable circuit simulator for analog spice circuit simulation, digital and mixed circuit simulation/

this may be what you want....i am not sure.....have a look. "Tina Pro - The Complete Electronics Lab Edison - Multimedia Lab for Exploring Electronics" ...   also CircuitMaker which you may know.

CircuitMaker Student Edition

Ssimulation program.... helpful for learning about circuits, testing designs or analyses, and even just drawing schematics for reports.