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1  Using Arduino / Project Guidance / Re: elechouse fm transmitter hanging on fmtx_init on: December 13, 2013, 03:16:51 am
First apologize for the trouble brought to all your guys by the FM modules from
This module was designed 2 years ago.
We knew that the on the chip datasheet it recommends 1.6~3.6V.  The chip has an LDO inside. However, in the limit testing, we kept this module working under 5V for 1 month. There is no problem. And we tested all the modules one bye one with 5V from Arduino. All work ok.
Later we understand it was wrong to wrote 5V even it could work under 5V. We need to follow the rules.
We might ignore other factors, such as that 5V might be the max voltage it could work with. Unstable 5V power supply may cause problem.
 In fact, there were customers reporting that the module had problem. For those we could not help fixing the problem, we shipped again, but  just in a few cases.  And the new module had solved the problem.
We are upgrading this module to new version now. 2 months before,  we planned to discontinue this module. However, later  we decided to upgrade it . We are prepared for replacing any defective FM V1 module for our customers in the future.
If you FM module got problem, just contact us.
2  Products / Arduino Due / Re: [Finally a working EMAC library] Connecting an Ethernet PHY to Arduino Due on: May 30, 2013, 09:00:21 pm
We know it is not perfect. While designing it, we didn't consider its compatibility with other modules in hardware. The best choice would be a Due shield which contains PHY chips. But we think we should do that later. As this library is not finished yet, a small and cheap PHY module would be better. That's how it comes. Sure later there will be a shield for Due to have all on it.
3  Products / Arduino Due / Re: [Finally a working EMAC library] Connecting an Ethernet PHY to Arduino Due on: May 30, 2013, 03:59:57 am
Please allow me to tell everybody who might be interested in Due-Ethernet. You could find a hardware kit for developing this libaray here:
On ebay click here
On official web click here
We hope this kits could help those software guys who are less patient and sick of handing wires.
4  Products / Arduino Due / Re: RTC cann't running well in arduino DUE, because DUE's reset connects NRSTB on: May 20, 2013, 07:57:34 am
Acctually i think you could try this Due-compatible board:
The NRST pin is available on this board.
5  Products / Arduino Due / Re: [Finally a working EMAC library] Connecting an Ethernet PHY to Arduino Due on: April 15, 2013, 10:28:23 am

Hope it could make things easy
6  Products / Arduino Due / Re: When is Due is due? on: December 26, 2012, 02:43:48 am
I have the [sarcasm]paid version of eagle[/sarcasm] and I can see all 4 layers, Top, Route 2, Route 15, Bottom.  The 2 inner layers are GND and power plain respectively.
I have a question.
Recently i made an arduino viriation board. I want to offer the source file to users.
I designed it with Altium Designer DXP. Now I am working on Eagle version.
I just want to know, is it good to offer the DXP source file? Or is it better to offer the eagle files after i finish it?
I am not sure if the DXP file could help users since i see eagle seems to be more popular.
7  Products / Arduino Due / Re: When is Due is due? on: December 19, 2012, 10:08:17 am
All the vias seem go through.
I could still be 4 layer, many fab houses don't allow blind or buried vias or charge more for them so many (most?) people just use through vias.

We have discussed the movement of that chip and other inconsistencies between the released CAD files and the real thing before. It has never been resolved AFAIK.

Well, I am not sure if it is 4-layer or not. But i see no reason for this board to be 4-layer. I mean, 2-layer could also work.
Even though Arduino published different eagle file in purpose, i could understand. There are so many copies of Arduino board which infringe Arduino trademark. It is too easy for those factories to make the copies. If Arduino publishes different CAD files, the copy boards become different. For arduino, that is a good way to protect themselves.
8  Products / Arduino Due / Re: When is Due is due? on: December 19, 2012, 01:02:48 am
The eagle file is 4-layer pcb. The actual board is 2-layer.
What! I know there's been some argy bargy about the posted files not being the actual files, but to go from 4 layers to 2 layers doesn't seem practical. That would be a total re-lay of the board to arrive at an inferior product.

Unfortunately it is true.
Look at the following picture. In the eagle file, there is a chip between the headers. However, actually there is no chip on the board i received. And the chip is gone in the pictures on Arduino DUE product page. The eagle file is 4-layer. But i can't see any symbol on my board indicating this board is 4-layer. All the vias seem go through.
9  Products / Arduino Due / Re: When is Due is due? on: December 18, 2012, 08:45:10 pm
I bought two from Arduino with the help of my friend.
However, the board is different from the eagle file in official website. The eagle file is 4-layer pcb. The actual board is 2-layer.
I found many producers begins to copy the board. But it is easy to distinguish the real and the copy.
The attached pictures could show the difference.
The one on the box is the same with the eagle file
The real board are the one we receive.
10  Products / Arduino Due / Re: More ideas for new Arduino DUE compatible board on: December 18, 2012, 08:26:35 pm
Hi sweansw,

Just to make sure I follow, are you the person to have actually build then soldered the Taiji-uino as shown in your picture ?

Actually it was my friend and me who did the work together. It would have been a big challenge if i finish it by myself in one month, since I have my work to do.
11  Products / Arduino Due / Re: More ideas for new Arduino DUE compatible board on: December 18, 2012, 08:19:19 pm
The LED on pin 13 is most useful at times, especially during debugging, so it would be wise to leave it, IMHO.
Actually the PC30 and PA21 are connected with leds. We can use those instead.
12  Products / Arduino Due / Re: More ideas for new Arduino DUE compatible board on: December 17, 2012, 12:24:49 am
I tried but didn't success
I posted more information in the topic:,136717.15.html
13  Products / Arduino Due / Re: Solution for the 5V vs 3.3V problem on: December 17, 2012, 12:20:05 am
Here's the schematic & layout, please create a version with the parts you are suggesting.
Top & bottom mount surface mount headers would be one way to keep the physical board the same size, as long as its cut back from the USB header.
I tried the TXB0108 and finally gave up.
The blue boxes in the attached picture contain 3 pcs pf TXB0108.
I made the beta board and tested it.
While I test the TXB0108 5V output with voltmeter, the voltage is 3V.
However, I test it with oscilloscope, the output is 5V. I touch the wire or chip with my finger, the voltage became unstable.
Well, I think, the TXB0108 is easy to go into self-excited oscillation process. And the load capacity is small. If I connect other devices to it through long cables, such as a digital sensor, the output may have problem. However, if I intert the sensor in the header of the beta DUE board directly, it works fine.
I tried many time but still didn't success.
Not sure if the TXB0108 performs not good enough.
14  Products / Arduino Due / More ideas for new Arduino DUE compatible board on: December 14, 2012, 01:44:53 am
About a month ago I bought 2 pcs of Arduino DUE board from an Arduino distributor. After receiving the board, I found that the board is different from the official Eagle source file found on Arduino website.
The board looks very good. But we still have some ideas to improve it. I began to think about build a compatible version. After a month, we made some process. I made an beta board, soldered by hand.

Here is the changes we made from the official Arduino DUE:
1. Remove the led on pin 13. Well, i fact I don't know exactly why I want to remove this led. Although this led will not affect the output of pin 13 on Arduino DUE now, I just want it to be simple. My feeling said, remove it. I hope you guys could give some suggestion.
2. Remove the ATmega16U2. Since we could upload sketch from native USB now, I think the programming usb is not irreplacable any more. However, I breakout pins for external ATmega16u2 downloader (if any in the future). I think, many boards could share one downloader, like Arduino Mini. And the pins also make it possible for wireless downloaders.  On some occasions,  wires are annoying. I am thinking about the wireless downloader now.
3. breakout all the unused pins. Maybe those pins will not be used in most cases. But i believe it will be used one day.
4. breakout the Ethernet pins. I can see those pins on Arduino schematic. However, i guess due to limited space, finally the pins are gave up. Since i removed the ATmega16U2, there is space for those pins. Hopefully one day there will be ethernet library for those pins.
There are also some small changes in the schematic. But they are not important.
Here I need to collect new ideas to improve it further. Maybe several weeks later I will plan to sell those boards. But before that, anything else needs to be improved to Arduino DUE board?
15  Forum 2005-2010 (read only) / Syntax & Programs / Re: How to do parallel output efficiently on: May 11, 2010, 02:27:07 pm
thank you so much. Would you please give me some suggestion or recommend some material about systematical Arduino programming learning?
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