programmable timer uA2240cn

[bigal_scorpio]

Hi to all,

I have some uA2240cn timer chips, which I purchased hoping to use them as easily as the trusted old 555s that I have always used.

Alas the info on them in the only datasheet I can find is slightly beyond my limited understanding of electronics and to be honest I don't have the slightest idea of how they work, and I can't find a single schematic on the net that uses them.

I was hoping to build a couple of timers, one is simply a monostable to delay turning on a relay by about 20 minutes, and the other I need is an astable that will turn on a relay for between 3 to 10 minutes and then off for between 2 to 5 minutes repeatedly. The latter is for some disco lighting that depending on the surrounding temp, overheats if run constantly!

If anyone would take pity on me and help to design these circuits or help me to understand the basic workings of the uA2240cn I would be most beholding to them. I am not a complete novice with electronics but have been out of the game for 20 odd years and just seem it harder and harder to take things in nowadays

Anyway thanks for looking and keep up the excellent forum!

Regards..............Al

 

[ericgibbs]

hi Al,

That chips got more grey hairs than me! Have you seen the date?

If no one else steps forward, someone who has used the chip before, youv'e got my email addr, drop me a line and we will figure it out.

From a quick read of the datsheet, it looks straight forward, its an osc with an inbuilt 8 bit binary counter, bit like a HEF4060.

Regards

 

[bigal_scorpio]

Thanks Eric

hi Al,

That chips got more grey hairs than me! Have you seen the date?

If no one else steps forward, someone who has used the chip before, youv'e got my email addr, drop me a line and we will figure it out.

From a quick read of the datsheet, it looks straight forward, its an osc with an inbuilt 8 bit binary counter, bit like a HEF4060.

Regards

Hi Eric, hadn't noticed the date hehe, it just seemed what I needed for the projects at the mo.

I will gladly take up your offer of help if someone doesn't jump in within the next few days.

BTW did you get time to look at my lists? Is any info wrong or you can add to any?

Regards........Al

 

[k7elp60]

I thought the 2240 looked familiar. I found a complete chapter in one of my old text books about the EXAR XR-2240. It really dates me I graduated from college in 1981 and the text book was published in 1977. But I would be glad to read up on this IC and give some help.

 

[ericgibbs]

hi Al,

Look here: **broken link removed**

A section covers the XR-2240 as a timer.

 

[k7elp60]

Here is a design for the 20 minute delay to turn on a relay. From what I can figgure out when the power is applied the 2240 automatically powers up in the reset mode and all the outputs are a logic level 0. The CD4103 (dual D F/F) latches to on to the time delay set by the timiming rc on pin 12 of the 2240. The rc connected to pin 4 of the 4013 is to insure the Q output is low in power up.
Hope this helps

 

[ericgibbs]

Here is a design for the 20 minute delay to turn on a relay. From what I can figgure out when the power is applied the 2240 automatically powers up in the reset mode and all the outputs are a logic level 0. The CD4103 (dual D F/F) latches to on to the time delay set by the timiming rc on pin 12 of the 2240. The rc connected to pin 4 of the 4013 is to insure the Q output is low in power up.
Hope this helps

hi K7,
I believe 'Al' , aka 'bigal' is posting a chip to me, I'll give your circuit a try, let you know.

Thanks.

 

[bigal_scorpio]

Hi Ned,

Thanks for the circuit, I'll give it a try and let you know what happens.

Fingers crossed I'll have a working timer with a bit of luck and your help!

Thanks again Ned............Al

 

[bigal_scorpio]

Hi Eric,

Yes I have posted a 2240 to you, it should arrive tomorrow (thursday) with any luck, sent it first class today, so if the GPO is on form and not on strike, you could be timing very shortly!

All the best...........Al

 

[ericgibbs]

hi Al,
Received the ic OK.

Got a couple of circuits working, monostable and astable.

Will post a drawing later.

Regards

 

[k7elp60]

Here is the circuit for the double time. I am using the fact the on power up or when reset the output of the 2240 to at logic level 0 to turn on the PNP transistor. If you need adjustable times use a similar circuit that I posted earlier.

 

[ericgibbs]

hi Al,

This circuit will give a 20 minute delay before energising the relay, after the 'Trig p/b is pressed'.

This should cover project number one of your thread for the original post.

I'll post the ON/OFF timer sequence later.

BTW, your HCF4013 are not 'D type F/F's', check the datasheet.
EDITED: download 3 different datasheets for the HCF, two say its a gate and one says its a F/F...??

Let me know when you have the circuit working, it works on my test bench OK.

PS: you didnt include a return address in your package, so that I can send the ic back.

 

[ericgibbs]

hi Al,

Drawing of Astable Timer attached.

Enjoy!...

 

[bigal_scorpio]

Thanks for all the help guys!

Just thought I would let everyone who helped me with this problem know that at last I have working timer circuits, and its a very handy timer at that now.

Special thanks to K7elp60 and Eric Gibbs, who both put time and effort into helping a noob for no other reason than being good blokes.

I can't thank you enough and hope one day I can return the help.

Thanks again...........Al

 

[k7elp60]

Just thought I would let everyone who helped me with this problem know that at last I have working timer circuits, and its a very handy timer at that now.

Special thanks to K7elp60 and Eric Gibbs, who both put time and effort into helping a noob for no other reason than being good blokes.

I can't thank you enough and hope one day I can return the help.

Thanks again...........Al

Thankyou for your kind words, I am glad I could help you
Ned