Manufacturing ...

Hello,

I have a problem:

Our controller V3 works great (maybe 3000 parts in the market) with our display V3. They communicate via I2C (16F876 - 16F872). The producer has soldert a lot of 2,7k pullups and at last 4,7k pullups (poland...).
They work great!

Now, we have our display V4 (+PWM for LCD +RGB-backlight) and it works great with controller V3.
Our controller V4 (18F4585) works great with both displays.

The software is nearly the same...

Yesterday we have a problem:
The I2C-communication is bad. A display V4 works on controller V3 but not really on a controller V4. (MSSP receives no bytes)
Sometimes I put my hand over the display - it works, or I touch the display - it works - or not...

Yesterday night i checked out the software. I set down the speed of the I2C to maybe 60kHz - it works. Back to 100kHz - it works. Up to 300kHz - it works. ???

Today I checked again...
A few days ago we have changed the pullups from 4,7k to 3,3k - that may be the problem. But all people tell, the lower the pullups, the better the signal. (signal form is ok). Inserting 10k pullups - it works. And why does the 2,7k pullup worked so well ?

Where is my problem ?
Pullups to low ?

I find 4K7 pull-up's good from one device on the I2C Bus, right up to about 8 devices on the I2C Bus. Have you put a scope on the Clock and Data lines to see how clean and square the pulses are?

If you are putting your hand over the product and it affects how it works, looks like a decoupling/noise problem. Your I2CBus is pretty resilient and should not be affected. You may need at add some 100nF's around your Vdd and perhaps improve the grounding. It is possible the problem is not with your display, but with your controller. The 18F's are a lot more intollerant of noise. Another thing to look at is if you are using a crystal, if it's being used in weak XT mode instead of HS mode (higher level of drive), your hand approaching it may just add enough extra capacitance to stop it from working.

PS... message me off-list, I'd like to know who you use to manufacture in Poland, what they're build quality is like, and how cost effective they are to use. Obviously the labour is cheaper than Germany, but how much cheaper? Always looking for good intelligence on where to get things made cheaper...

Quote:

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Originally Posted by Melanie

...Always looking for good intelligence on where to get things made cheaper...

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Goto Here!


Here:
Where I am.




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Soon... but not yet Sayzer... Turkey is not in EC yet, which means shipping parts to and from a non-EU country is prohibitive on Customs paperwork and this negates the savings made in lower-cost labour.

Please allow me to provide the following information.

On 31 December 1995 the customs union between Turkey and the European Union came into effect. Goods can travel between the two entities without any customs restrictions.


http://en.wikipedia.org/wiki/EU-Turkey_Customs_Union
http://www.gumruk.gov.tr/english/con...3&cId=b_origin

and also pls visit http://www.deltur.cec.eu.int/english/ei-gumruk.html


Lets negotiate Melanie! :-)



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I will send you details to quote by PM... gimme a couple of days to organise the specification and get some pictures taken so you know what's involved...

Melanie,

My apologies first, as this is not a technical reply, but sometimes, one needs to post these things, to inform people since they don't always keep up with politics.

Just for your information make sure you understand that dealing and supporting a country like Turkey which refuses to recognise an EU member and does not allow free trade with it, violates its citizens human rights, still refusing to comply with UN resolutions to get the hell out of Cyprus, after more than 30 years of occupation, and a whole lot more actions and behaviours totally incompatible with the form, function and spirit of EU directives, one does not really save a couple of euros in every pcboard, but looking deeper, one needs to ask, what is the price of morality......Money is not everything.

Sayzer, nothing personal with you. I don't have anything personally against you, just your goverment and military. I hope you suport a free and truly democratic Turkey. We would love to have a good neighbor one of this days.

Zenon

I agree with you, but you could say this of many countries… Microchip manufactures in many far-Eastern countries with atrocious Human Rights records. We don’t boycott Microchip, and we’re buying their products. We all buy and deal with China, a country whose record in Tibet is just as bad - yet I don't hear too many dissenting voices (apart from the Dalai Lama). Only sixty years ago Japan was committing mass genocide in Asia, and Germany was doing the same in Europe, yet everyone today drives BMW’s and carry Sony Walkmans.

Fortunately I’m an Engineer. Engineers build civilisations – I leave it to politicians to destroy them.

I don’t make the final decision as to what is manufactured where. This is done by the Buying Department and ultimately by the person who signs my paycheque, but it is my job to provide him with information necessary to make decisions. If those decisions were solely based on price, then I know I can hire good Assembly staff in India for $4 per day and Engineers and Managers for $10 per day, but the world is more complicated than that.

I have nothing more to add to Melanie’s post above.
It is just enough and self satisfactory answer.

Also, I appreciate Zenon saying that this is not personal. But, it seems it is personal to you, Zenon; no matter how much you insist that it is not.

Meanwhile, you guys are buying TVs, cars, foods, textiles, cleaning supplies etc. from Turkey, already. Approx. 35% of TV units sold in Europe are made in Turkey, as such, approx. 75% of refrigerators, 45% food processors, Dish Washers and Washing machines too (with PIC controllers inside :-), list goes on.

To add from higher tech, F16 fighters, nano level applications, remote controlled surgery operations and their associated devices etc.

In short, we are already selling millions of units to Europe and USA.

I see opportunity Zenon, try to take advantage of it while the government supports FDI (Foreign Direct Investment) by providing privileged resources and tax cuts to foreign investors. Even reserves free land for factories etc. 23 million young people under 30yrs of age and high tech skills. I am not good in math, you do the math.

Quote:

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Originally Posted by Zenon

Melanie,

My apologies first, as this is not a technical reply, but sometimes, one needs to post these things, to inform people since they don't always keep up with politics.

Just for your information make sure you understand that dealing and supporting a country like Turkey which refuses to recognise an EU member and does not allow free trade with it, violates its citizens human rights, still refusing to comply with UN resolutions to get the hell out of Cyprus, after more than 30 years of occupation, and a whole lot more actions and behaviours totally incompatible with the form, function and spirit of EU directives, one does not really save a couple of euros in every pcboard, but looking deeper, one needs to ask, what is the price of morality......Money is not everything.

Sayzer, nothing personal with you. I don't have anything personally against you, just your goverment and military. I hope you suport a free and truly democratic Turkey. We would love to have a good neighbor one of this days.

Zenon

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Independence from the UK was approved in 1960 with constitutional guarantees by the Greek Cypriot majority to the Turkish Cypriot minority. In 1974, a Greek-sponsored attempt to seize the government was met by military intervention from Turkey, which soon controlled almost 40% of the island. In 1983, the Turkish-held area declared itself the "Turkish Republic of Northern Cyprus", but it is recognized only by Turkey. UN-led talks on the status of Cyprus resumed in December 1999 to prepare the ground for meaningful negotiations leading to a comprehensive settlement.

(Click to enlarge).
http://img10.picsplace.to/7/thumbs/cy.PNG

More about:

http://www.cyprus-conflict.net/narrative-main.htm
http://www.cyprus-conflict.net

Luciano