School, hobby electronics

This material is not 'polished'!!

As I surf the net, I come across various things that I wish someone had told me about. In theory, one day it will all be available in the polished sections of my website. In the meantime, if you're willing to 'dig' through some disorganised material, you may be rewarded with gems'! School, hobby electronics.

This material is mostly about doing things with digital electronics, including PICs and 6802 microprocessors. Not much about how to add soundcards, hard drives, etc, to a pc. However, there is material on circuits you might want to build and connect to a pc via a parallel port, ISA bus, etc.

In some cases, the text is snipped from other sources. Therefore, among other things, the personal pronoun may not refer to the editor of this page. If, on the other hand something is identified as coming from 'TKB', he IS the pages's editor!

Material from earlier versions of this page has been 'polished' into more organised pages. Click here to visit them.

Oops... the page WAS in two sections... general stuff at the top, then notes about specific problems, projects, products on offer (e.g. digital i/o card) in second section. I messed it up a bit, but will try to re-sort it in ue course.

Click here for 'unpolished' material about using an MS-DOS / Windows computer's parallel port to control things or sense the 'outside world', or click here for 'polished' material.
Ad from page's editor: Yes.. I do enjoy compiling these things for you... hope they are helpful. However.. this doesn't pay my bills!!! If you find this stuff useful, (and you run an MS-DOS or Windows pc) please visit my freeware and shareware page, download something, and circulate it for me? Links on your page to this page would also be appreciated!

Click here to visit editor's freeware, shareware page.

General Stuff

(Weird... and not too easy to see or navigate... but electronics enthusiast..)

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For information on pinouts of all the IBM connetors.. specifically the 16 bit data bus, see:

The MNT-101 series preprogrammed microcontrollers were designed to perform high-speed serial-to-parallel conversion from a standard RS-232 data source. Baud rate is determined by the speed of the ceramic resonator or crystal attached to the microcontroller. Up to 7 MNT-101 can be attached to a single RS-232 serial port providing a total 56 individually addressable output bits. (You can upgrade to a maximum of 1024 com ports giving you: 1024 x 56 = 57344 devices to control). The name jumpers N1, N2, and N3 determine its address on the serial port.

Addresses: (Names)

The Name Select Pins are used to assign a name to the chip. The chip will only obey an ASCII comand if the command is preceded by it's selected name.

When the name is selected to be ALL, then the chip will ignore all naming protocols and it will output the on or off command of any byte that is input (ASCII)


If a proper name is selected with the name select pins then the MNT-101 will be able to obey three commands. ({CR} indicates a carraige return character)

Turn a pin on: {name} N {pin number} {CR}
EXAMPLE command string: 2N3{CR}
(device named "2" turns on pin 3)

Turn a pin off: {name} F {pin number} {CR}
example command string: 5F2 {CR}
(device named "5" turns off pin 2

Output a Byte: {name} P {binary byte} {CR}
Example command string: 1P{byte} {CR}
(device named "1" outputs the value of the byte)

Truth Table:

N1 N2 N3 Name
1 1 1 All (all chips enabled)
1 1 0 6 (device Named SIX )
1 0 1 5 (device Named FIVE)
1 0 0 4 (device Named FOUR)
0 1 1 3 (device Named THREE)
0 1 0 2 (device Named TWO)
0 0 1 1 (device Named ONE)
0 0 0 0 (device Named Zero)

When all name jumpers are installed, the MNT-101 performs a raw serial-to-parallel conversion. In turn the output bit could be connected to a switching relay, Solid state relay, solenoid, motor or triac to power on or off any electronic or electrical device.

The system uses two wires from the Com port and can run upto half a KM.

Since I have recieved many request for the circuit diagram, I am enclosing my website for you to view it: (NO www)

If you need further info, you may request for a general catalog which contains our whole line of chips to solve common automation problems.

#05-16 International Plaza
10 , Anson Road Singapore 079903 Tel: (65) 4426897 Fax: (65) 2439309

Email: >> emaiiled to check URL

Naresh Melwani, Technical Manager Nashtech

Material from earlier versions of this page has been 'polished' into more organised pages. Click here to visit them.

Here is how you can contact this page's editor.
Link to 'My Desk Pile' main page
Link to a second page of "Desk Pile" electronics stuff