PICAXE to CMOS
- Thread starter Vroom
- Start date
westaust55
Moderator
Yes, please slow down and step through problems more clearly.
Does "Whiteboard" = breadboard ??
Here is my interpretation:
From the datasheet ( http://focus.ti.com/lit/ds/symlink/cd4514b.pdf ),
for the 4514 CMOS chip, with a 5V supply the outputs should be at least 4.95 V with expected current loading
Total chip max supply is 10 mA
Also each output can ONLY source approx 3mA at 5V supply
With an output current of 1 mA, the output voltage will be ~ 4.6 V.
at 3mA output current the output voltage will fall to as low as 2.5 Volts.
See attached datasheet extract.
Your LED with a say nominal 2V Vforward and 390 Ohm series resistor results in apporx 7.7 mA current into LED if supply at output was ~5V.
Therefore I suggest that you are overloading the outputs and pulling the voltage down.
In simple terms you are not using the right chip for the LED driving.
Does "Whiteboard" = breadboard ??
Here is my interpretation:
From the datasheet ( http://focus.ti.com/lit/ds/symlink/cd4514b.pdf ),
for the 4514 CMOS chip, with a 5V supply the outputs should be at least 4.95 V with expected current loading
Total chip max supply is 10 mA
Also each output can ONLY source approx 3mA at 5V supply
With an output current of 1 mA, the output voltage will be ~ 4.6 V.
at 3mA output current the output voltage will fall to as low as 2.5 Volts.
See attached datasheet extract.
Your LED with a say nominal 2V Vforward and 390 Ohm series resistor results in apporx 7.7 mA current into LED if supply at output was ~5V.
Therefore I suggest that you are overloading the outputs and pulling the voltage down.
In simple terms you are not using the right chip for the LED driving.
Attachments
Sorry Vroom, your post is VERY hard to understand.
If the language is difficult then I suggest you post a SCHEMATIC or DRAWING.
Please use ARROWS to indicate your measurement 'Test Points'.
Perhaps post in your First language and others here can translate (?).
If I understand you correctly you are querying the Output voltage of a 4514 CMOS.
I used a CD4514 about 10 years ago and had no probs.
The DATA SHEET for the CD4514 shows the O/P voltage should be approx Vdd-0.05 Volts.
You have not said which version of the 4514 you are using , BUT, you will have seen in the Data Sheet that the output CURRENT is very limited. Just a few mA.
You may be OVERLOADING the output and dragging the voltage down.
Try measuring again after you have REMOVED the LEDs.
If the language is difficult then I suggest you post a SCHEMATIC or DRAWING.
Please use ARROWS to indicate your measurement 'Test Points'.
Perhaps post in your First language and others here can translate (?).
If I understand you correctly you are querying the Output voltage of a 4514 CMOS.
I used a CD4514 about 10 years ago and had no probs.
The DATA SHEET for the CD4514 shows the O/P voltage should be approx Vdd-0.05 Volts.
You have not said which version of the 4514 you are using , BUT, you will have seen in the Data Sheet that the output CURRENT is very limited. Just a few mA.
You may be OVERLOADING the output and dragging the voltage down.
Try measuring again after you have REMOVED the LEDs.
westaust55
Moderator
So now that is sorted out (ie overloading the 4514 as suggested), you could try something such as 8-channel ULN2803 darlington array DIP packages as the interface between the 4514 and the LED's which may allow you to keep the suppy at 5 Vdc.
There maybe other simple LED driver chips to use for the interface but I am sure you can Google for those.
There maybe other simple LED driver chips to use for the interface but I am sure you can Google for those.
OK, so you now understand about overloading.
And, for the record, a PICAXE can NOT output 100mA from a single port.pin. Don't try it.
READ the PICAXE Manuals and/or PIC Data Sheets fro electrical characteristics.
Back to the second question.
Read the Data Sheet for your device.
Read the section where it specifies (logic) Input voltages at given Vdd.
For the CD4514 operating at 10V it needs a logic input High/Low (On/off , 1/0) of >7V (high) & <3V (Low). It'll be even more at 12V Vdd.
So, a PICAXE at 5V could NOT (directly) control a CD4514 @12V.
Once again, you have not specified which variant of the 4514 your are using , so YOU will have to read the Data Sheet for your device.
But why do you want to do this? To drive an LED harder? This is NOT the way to do it.
Transisters or a driver chip are the way to go. Do the calcs.
Jeez, westy's in there like a terrier down a rabbit hole.
And, for the record, a PICAXE can NOT output 100mA from a single port.pin. Don't try it.
READ the PICAXE Manuals and/or PIC Data Sheets fro electrical characteristics.
Back to the second question.
Read the Data Sheet for your device.
Read the section where it specifies (logic) Input voltages at given Vdd.
For the CD4514 operating at 10V it needs a logic input High/Low (On/off , 1/0) of >7V (high) & <3V (Low). It'll be even more at 12V Vdd.
So, a PICAXE at 5V could NOT (directly) control a CD4514 @12V.
Once again, you have not specified which variant of the 4514 your are using , so YOU will have to read the Data Sheet for your device.
But why do you want to do this? To drive an LED harder? This is NOT the way to do it.
Transisters or a driver chip are the way to go. Do the calcs.
Jeez, westy's in there like a terrier down a rabbit hole.
That true... but note the limitations if you start using more than one Output pin.
You have a limit on that chip of 250mA TOTAL output.
Or 200mA from any port (e.g. All of port B. B.0 - B.7)
Does that make sense?
Note: 40X2 = 18F4520 . If you want FULL electrical details then download the latest PIC data sheet from Microchip .
You have a limit on that chip of 250mA TOTAL output.
Or 200mA from any port (e.g. All of port B. B.0 - B.7)
Does that make sense?
Note: 40X2 = 18F4520 . If you want FULL electrical details then download the latest PIC data sheet from Microchip .
westaust55
Moderator
The 25 mA for PICAXE outputs is typically the absolute maximum per pin.
Typically it would be best to suggest that you should design for not greater than 20 mA on any one IO pin.
There are then additional limits for the total current of each port (up to 8 IO pins) and another total current limit for the entire chip. These vary considerably depending upon which PICAXE chips you are using.
For some chips the total for the chip may be as low as around 95 mA whereas for others the chip total may be around 250/300 mA.
Best to read the relevant PIC datasheet.
Typically it would be best to suggest that you should design for not greater than 20 mA on any one IO pin.
There are then additional limits for the total current of each port (up to 8 IO pins) and another total current limit for the entire chip. These vary considerably depending upon which PICAXE chips you are using.
For some chips the total for the chip may be as low as around 95 mA whereas for others the chip total may be around 250/300 mA.
Best to read the relevant PIC datasheet.
hippy
Ex-Staff (retired)
The LED does not "use" 5-10 milliamp, you have to use a resistor to limit the current to 5 or 10 milliamps.
The resistor depends on the voltage drop the LED will have (from a datasheet, but generally different colors take different voltages). Red is ~1.8 blue and white ~3.2-3.6 volts, and usually specified at ~20 milliamps for 3 and 5mm common indicator leds. (for a seven segment display, use the datasheet).
You probably won't get into it, but the chip package is also limited to a maximum power dissipation as well. Not usually of any concern unless you are pushing it with elevated temperatures.
Andres Rodriguez
New Member
Last edited:
Yep. It's always good to remember that this is a world-wide forum with many members for whom English is not their first language. Also, there are those with disabilities as well, who may be having a tough time communicating clearly despite their best efforts.
I realize it's easy to become irritated with those who are simply sloppy with their posts, but in this medium we can't safely make any assumptions regarding the circumstances within which each poster operates. It's really best to be polite and as helpful as possible with everyone in order to bridge any communications gaps that exist for whatever reason.
Please play nice.
I realize it's easy to become irritated with those who are simply sloppy with their posts, but in this medium we can't safely make any assumptions regarding the circumstances within which each poster operates. It's really best to be polite and as helpful as possible with everyone in order to bridge any communications gaps that exist for whatever reason.
Please play nice.
westaust55
Moderator
Overload of the CMOS 4514 chip is highly likely to result in higher temperatures within the chip that will result in failure. That failure may not be immediate but the chip circuit is being overstressed and could fail at some time unknown.
westaust55
Moderator
@Marmitas and John West,
In defense of manuka, his input to this forum is usually of a very high standard and helpful.
I too found that vroom's request difficult to understand in the first instance with 2.5 lines of text and four "and"s.
Vroom does not let us know his location in his forum ID so folks are left to make assumptions.
We had a recent case where many thought a fault keyboard was the problem. I could see that spelling errors were in fact "hitting" an adjacent key to that required.The poster did after several posts indicate a disablity and the mood became more pleasant.
Personally, I answer many posts here and many PM's that never receive an acknowledgment from those who pose the question. I have also answered many on the French section of the forum as well with similar "results".
In general most here do aim to be polite and politically correct. Frustration can arise on occasions however in general this forum is a happy and polite place to participate. Non other than Technical and hippy are paid to be here and respond to questions. The rest of the members here respond to the best of their ability and those with questions also need to respect that time to answer is given freely.
In defense of manuka, his input to this forum is usually of a very high standard and helpful.
I too found that vroom's request difficult to understand in the first instance with 2.5 lines of text and four "and"s.
Vroom does not let us know his location in his forum ID so folks are left to make assumptions.
We had a recent case where many thought a fault keyboard was the problem. I could see that spelling errors were in fact "hitting" an adjacent key to that required.The poster did after several posts indicate a disablity and the mood became more pleasant.
Personally, I answer many posts here and many PM's that never receive an acknowledgment from those who pose the question. I have also answered many on the French section of the forum as well with similar "results".
In general most here do aim to be polite and politically correct. Frustration can arise on occasions however in general this forum is a happy and polite place to participate. Non other than Technical and hippy are paid to be here and respond to questions. The rest of the members here respond to the best of their ability and those with questions also need to respect that time to answer is given freely.
westaust55
Moderator
Yes, some versions of the 74HC4514 do allow up to 25mA source (out of the pin) and 20 mA sink (into the pin)
but be aware that the datasheets for those chips also have a total current limit of just 50mA:
Thus if you are using in a conventional manner with the 1 out of 16 outputs pins active low and thus in current sinking mode then as only one is low at any time there should be no problems.
Vroom, listen to Westy !!!!!!
I haven't seen at ANY STAGE that you have specified the variant of the 4514 that you are using - I may have missed it in the fog.
I politely suggested you should inform us a while back.
This is a simple problem turning into a mountain.
If you are having trouble with the Data Sheet then try and get a friend to translate it for you.
My (1995) Harris CD4514 Data Sheet says:-
Io = 0.6mA @ Vdd=5V and Vo = 4.6V .
It also says.
Io = 1.8mA @ Vdd=5V and Vo = 2.5V
See that?!?!
Increasing the output load from 0.6mA to 1.8mA made the output voltage DROOP from 4.6V to 2.5V.
That should be a CLUE as to how feeble the output is.
Try and remember, these are old-fashioned chips designed to feed integrated or dicsrete DRIVERs.
And if you use them BEYOND there design specirfication then you are in the region of ABUSE.
As said, several times, you are now overloading them.
In this realm their behaviour and longevity is unknown and a simple case of 'tough titty' when they break.
If you push them too far then ouch! YOU have been warned (several times).
I thought earlier that you understood the need for an extra driver?
But I see now that you have found a variant with extra oomph.
Now you appreciate the benefit of reading Data Sheets.
A satisfied customer - good luck.
I haven't seen at ANY STAGE that you have specified the variant of the 4514 that you are using - I may have missed it in the fog.
I politely suggested you should inform us a while back.
This is a simple problem turning into a mountain.
If you are having trouble with the Data Sheet then try and get a friend to translate it for you.
My (1995) Harris CD4514 Data Sheet says:-
Io = 0.6mA @ Vdd=5V and Vo = 4.6V .
It also says.
Io = 1.8mA @ Vdd=5V and Vo = 2.5V
See that?!?!
Increasing the output load from 0.6mA to 1.8mA made the output voltage DROOP from 4.6V to 2.5V.
That should be a CLUE as to how feeble the output is.
Try and remember, these are old-fashioned chips designed to feed integrated or dicsrete DRIVERs.
And if you use them BEYOND there design specirfication then you are in the region of ABUSE.
As said, several times, you are now overloading them.
In this realm their behaviour and longevity is unknown and a simple case of 'tough titty' when they break.
If you push them too far then ouch! YOU have been warned (several times).
I thought earlier that you understood the need for an extra driver?
But I see now that you have found a variant with extra oomph.
Now you appreciate the benefit of reading Data Sheets.
A satisfied customer - good luck.
counsel for the defence
I too wish to defend Stan/Manuka.
He has contributed more than most people to this Forum.
He certainly has the biggest beard as he can use it as an antenna.
Vroom seems to be from Australia. Adelaide?
Maybe people jumped to the wrong conclusion wrt language ability?
Stan's comment may have been a little excitable, but it probably came from the frustration of having trouble understanding the question.
Let me stroll off at a tangent and explain ....
To other viewers I can assure you that the longer you spend on this Forum the more grumpy you get.
Us (We?) old hacks have seen thousands of questions.
The ones that drive us (well, me actually) up the wall are the ones with the following spec.
(BTW: When English is definitely the First language)
1. One great long unbroken paragraph.
2. No gaps, no capitals, lazy spelling (not tpyos) and punctuation.
3. Childish text-speak.
4. No drawings in many cases.
5. The sense that the questioner expects everyone else to spend more time on the answer than the OP spent cobbling some question together.
6. Drip-feed of information.
7. The assumption that we have bl**dy great Crystal Balls.
8. The > 200 OPs who never seem to learn anything.
9. Lazy buggers looking cut'n'paste answers.
My extra 'dislikes'.
1. People who say "thx" , "awesome" (when it's not) , "cool" (when it's not) , and "my bad" (aaargh!).
2. Creepy Sycophancy. "Aw <whoever> , you're right like always, you're great."- (so, please spend hours answering all my other Qus)
The problem is that this creeping frustration with people ,who have English as a First language , then spills over onto others who may struggle with the language - unfortunately 'tarring everybody with the same brush'.
That's the basic psychology.
It's usually unintended , but the results include slightly terse , inappropriate and unfortunate replies.
I am certain that, on occasions, when a question is unintelligible that many old Hacks simply click-off rather than say "What the hell are you on about?".
I am genuinely really pleased we have people like Chava who are fluent in several languages and competent. A real benefit to the Forum.
Even Westy seems to have bought a French-English dictionary and suddenly become bisexual
In conclusion, Ladies and Gentlemen...
One thing I DO know ; Stan would never intend to be offensive.
(Even if he glued photos of breadboards all over my house, car and cat I'd still think he is a Good Bloke!)
I too wish to defend Stan/Manuka.
He has contributed more than most people to this Forum.
He certainly has the biggest beard as he can use it as an antenna.
Vroom seems to be from Australia. Adelaide?
Maybe people jumped to the wrong conclusion wrt language ability?
Stan's comment may have been a little excitable, but it probably came from the frustration of having trouble understanding the question.
Let me stroll off at a tangent and explain ....
To other viewers I can assure you that the longer you spend on this Forum the more grumpy you get.
Us (We?) old hacks have seen thousands of questions.
The ones that drive us (well, me actually) up the wall are the ones with the following spec.
(BTW: When English is definitely the First language)
1. One great long unbroken paragraph.
2. No gaps, no capitals, lazy spelling (not tpyos) and punctuation.
3. Childish text-speak.
4. No drawings in many cases.
5. The sense that the questioner expects everyone else to spend more time on the answer than the OP spent cobbling some question together.
6. Drip-feed of information.
7. The assumption that we have bl**dy great Crystal Balls.
8. The > 200 OPs who never seem to learn anything.
9. Lazy buggers looking cut'n'paste answers.
My extra 'dislikes'.
1. People who say "thx" , "awesome" (when it's not) , "cool" (when it's not) , and "my bad" (aaargh!).
2. Creepy Sycophancy. "Aw <whoever> , you're right like always, you're great."- (so, please spend hours answering all my other Qus)
The problem is that this creeping frustration with people ,who have English as a First language , then spills over onto others who may struggle with the language - unfortunately 'tarring everybody with the same brush'.
That's the basic psychology.
It's usually unintended , but the results include slightly terse , inappropriate and unfortunate replies.
I am certain that, on occasions, when a question is unintelligible that many old Hacks simply click-off rather than say "What the hell are you on about?".
I am genuinely really pleased we have people like Chava who are fluent in several languages and competent. A real benefit to the Forum.
Even Westy seems to have bought a French-English dictionary and suddenly become bisexual
In conclusion, Ladies and Gentlemen...
One thing I DO know ; Stan would never intend to be offensive.
(Even if he glued photos of breadboards all over my house, car and cat I'd still think he is a Good Bloke!)
westaust55
Moderator
Yes, and removed the text of each post he made.
Which is a pity as it makes this thread look strange. ANswer with no questions.
IMHO we were more critical of those who had taken something of a "shot" at manuka rather than vroom's posts.
I geuss he got the answer he needed and took it, and the questions, with him
Which is a pity as it makes this thread look strange. ANswer with no questions.
IMHO we were more critical of those who had taken something of a "shot" at manuka rather than vroom's posts.
I geuss he got the answer he needed and took it, and the questions, with him
BeanieBots
Moderator
I take that as VERY insulting and am unlikely to ever respond to such a poster again.
Vroom, please explain yourself.
Vroom, please explain yourself.
Andres Rodriguez
New Member
I Agree with BB
slimplynth
Senior Member
I hope that wasn't me
though in my defence it may have been 'my time of the month'... If i have.Something that cheesed me off a good few months back was a complete noob (I can't even remember the name) updating their original question after I'd pointed out an error.. at worse it made my response look stupid at best you'd think.. in the style of Alan Partridge "Why do I bother"
BeanieBots
Moderator
hippy
Ex-Staff (retired)
Let's please all take a step back, and not make an unfortunate situation any worse.
We have a very diverse membership and probably an even more diverse readership and not everyone has the same views and social values as others, aren't always as thick-skinned as some regulars may be, nor perceive a posting in the light it was intended. People struggling with English as a language will have problems posting, expressing themselves and understanding what they are being told and we have to be appreciative and tolerant of that. Even those with good English skills sometimes don't express themselves well and can have difficulty understanding things. That's a fact of life which we all have to deal with and we should do so with consideration of their feelings.
What makes this forum so great is that it is welcoming to all PICAXE users regardless of their experience and abilities and I don't think anyone wants to lose that, nor lose members should they perceive otherwise.
We have a very diverse membership and probably an even more diverse readership and not everyone has the same views and social values as others, aren't always as thick-skinned as some regulars may be, nor perceive a posting in the light it was intended. People struggling with English as a language will have problems posting, expressing themselves and understanding what they are being told and we have to be appreciative and tolerant of that. Even those with good English skills sometimes don't express themselves well and can have difficulty understanding things. That's a fact of life which we all have to deal with and we should do so with consideration of their feelings.
What makes this forum so great is that it is welcoming to all PICAXE users regardless of their experience and abilities and I don't think anyone wants to lose that, nor lose members should they perceive otherwise.
Slimmy, I've seen a few people do that.
Often their excuse is : "I went back and changed it to clarify the situation".
My codpiece! They went back and changed it because they thought that they looked a fool.
Every time they do that I think to myself " 'ere 'egos again! ". Emphasis on ego.
CDNG,
I think you'll find BB was being a little ironic. He has a robust pshyche.
And, you're right, a lot of people take it too seriously.
And some people actually enjoy being easily offended so that they can gob off and others can't moan.
It's the "I'll scweam and scweam and scweam" syndrome.
83% of the time you'll find it is some complete drip and 76% of people make up bogus statistics.
I don't insult people until I know them
Often their excuse is : "I went back and changed it to clarify the situation".
My codpiece! They went back and changed it because they thought that they looked a fool.
Every time they do that I think to myself " 'ere 'egos again! ". Emphasis on ego.
CDNG,
I think you'll find BB was being a little ironic. He has a robust pshyche.
And, you're right, a lot of people take it too seriously.
And some people actually enjoy being easily offended so that they can gob off and others can't moan.
It's the "I'll scweam and scweam and scweam" syndrome.
83% of the time you'll find it is some complete drip and 76% of people make up bogus statistics.
I don't insult people until I know them
BeanieBots
Moderator
Robust pshyche! You implying I'm fat?
I'll poke you with my knitting needle
I'll poke you with my knitting needle
My comment was not meant to be any sort of scold, just a general reminder to everyone of the realities of life on a world-wide forum. Manuka is one of my forum heroes, and has contributed far more to the forum than I'm ever likely to.
I'm just a very mellow guy who tries to smooth things over and help everyone get along. That sometimes leads me to say more than I have any right to or should.
Yes, even in my short time here I can see how very frustrating some posters can be, and how thankless the unpaid job of providing excellent PICAXE engineering support can be.
Why any of the experts here even bother to do it would seem a mystery to me, if I too did not feel the urge to help others do well with their PICAXE projects.
I'm just a very mellow guy who tries to smooth things over and help everyone get along. That sometimes leads me to say more than I have any right to or should.
Yes, even in my short time here I can see how very frustrating some posters can be, and how thankless the unpaid job of providing excellent PICAXE engineering support can be.
Why any of the experts here even bother to do it would seem a mystery to me, if I too did not feel the urge to help others do well with their PICAXE projects.
Last edited: