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Author Topic: Olimexino compatible?
brucemelle-
n
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Post Olimexino compatible?
on: May 27, 2013, 18:53
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Does the EPT-570-AP-U2 work on the ARM-based Olimexino-STM32? Pin voltages compatible?

EPT_User
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Post Re: Olimexino compatible?
on: May 27, 2013, 21:44
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Hi brucemellen, thanks for the question. I downloaded the STM32F103RBT6 datasheet and checked the Input/Outputs. They are 5 Volt tolerant and meet the TTL VIL and VIH voltage levels. So, the EPT-570-AP-U2 is compatible with the Olimexino-STM32 Rev D. The Input/Outputs of the EPT-570-AP-U2 board are selectable during programming of the CPLD. So, you can make them either inputs or outputs or they can be both, you just need to tri-state the output when using the pin as an input.

Let us know if you have any questions about programming the CPLD or the capability of the Active Host Software. We will also be posting video tutorials soon.

Thanks, EPT Team

brucemelle-
n
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Post Re: Olimexino compatible?
on: May 28, 2013, 23:32
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Thanks for responding. I was also (besides the Olimexino board) considering physical and voltage compatibility with the Maple board from leaflabs.com.

Looking further at your schematic, I assume you are using power from the Arduino board. In that the Olimexino (and Maple) instead supply 3.3V on what is usually (Arduino Uno) a 5V pin, is that going to cause problems with...
* use of the USB FT2232H Mini Module while on the Olimexino/Maple (is the mini-module taking power from your USB connection and is your USB power isolated from the 5V power shown on the schematics?),
* the few SN74LVC4245A on the board (will supplying 3.3V on Vcca allow it to function as just a translator)?,
* the D1 thru D4 LEDs (I don't know what mfr/part# is mounted on your board and am hopeful they will still light up using 3.3V, albeit dimmer),
* or concurrently using the Maple IDE with your FT2232H Mini Module under Win7x64
* or something else (I assume neither the Olimexino nor Maple have been yet tested)

EPT_User
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Post Re: Olimexino compatible?
on: May 29, 2013, 15:03
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Actually, the EPT-570-AP is designed to be powered from the 3.3V Regulator on the FT2232H Mini Module. You have pointed out a flaw in the schematic, R26 and R25 are not installed on the boards. R26 connects Pin 4 (+3.3V from Arduino) to EPT-570-AP +3.3V and R25 connects Pin 5 (+5V from Arduino) to EPT-570-AP +5V. The intention is that developers can program and test the EPT-570-AP separate from the Arduino. When the project is complete, R25 can be installed and let the EPT-570-AP power the Arduino. This is done because the EPT-570-AP board can command the USB port to output 500 mA. Also, if you don't need to run with the FT2232H Mini Module, you can install R25 and R26 and run from the Arduino power.

You have pointed out a significant flaws with the schematic, we did not include a Bill Of Materials. I apologize for our short comings, please bare with us while we work through our mistakes. I will update the schematic with the part No Stuffs and the BOM and upload it to the site later today.

The EPT-570-AP was designed with 3.3V to 5V voltage translators for use in the Arduino Uno market. The Olimexino and the Maple are native 3.3V devices, they really don't need these voltage translators. We could modify a version of the EPT-570-AP for the Olimexino/Maple your purpose. This would include removing the voltage translators and installing jumper wires. You would gain a lot of flexibility in the I/O's. The voltage translators work as a single port with one direction at a given time. Let us know if this is some thing you would be interested in.

brucemelle-
n
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Post Re: Olimexino compatible?
on: May 29, 2013, 19:57
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I was already guessing this is a relatively new product and fully understand you did not anticipate a need to work with Olimexino/Maple.
Based upon what you say, perhaps using tiny jumpers such as HPH1-A-32-UA pins with M50-1900005 shunts (both mouser) could be considered instead of resistors on future board revs. I would think you might want to consider triple pins so the choice is easily made between power from Arduino vs.the mini-module; power should be isolated from each other; you don't want a user to be able to toast something by crossing supplies.
I can see a need to most often leave the board on the Arduino for a project and sometimes concurrently use the mini-module and sometimes not - as I go between projects. I'm plannning to use the combo to learn and then build stand'alone PCBs that may communicate with a PC.
Lets think about how to bypass the voltage translators so the same board can work for all 'duino markets. Putting 24 triple jumpers does not seem to make initial sense, especially if things need to work without noise. Which exact CPLD part# are you using?
Sorry, I'm out of time for the day....

brucemelle-
n
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Post Re: Olimexino compatible?
on: May 30, 2013, 02:26
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Had a few further thoughts on the above etc....
Aren't there some relatively inexpensive CPLDs out there with more than 48 I/O pins that can have a 50:50 mix of 3.3V and 5V I/O that can do bidirectional translation like you have each SN74LVC4245A do? Could one replace the three SN74LVC4245A chips? Could it also then support 3.3V to 3.3V translation with a jumper change or different voltage supplied to the CPLD or reprogrammed for one or the other market?
Or I also see some shifter ICs that might allow not only shifting between 3.3V and 5V, but between 3.3V and 3.3V, depending upon whether Vcca is powered at 3.3V or 5V. Looking closer at the SN74LVC4245A datasheet, I wonder if 3.3V to 3.3V shifting will also work right now.
One limitation I also see is that a developer needs to be aware of the direction of each group of 8 pins and program the CPLD for it. Is that the way the CPLD needs to work, or is it just a requirement due to the SN74LVC4245A? If not a requirement of the CPLD, I'd want to group pins by 4's in that I believe you really only have 21 Arduino pins to work with. Do you really want to connect 4 bits to the Arduino's GND, AREF, and the last two of your 10pin header that don't exist on many Arduinos nor the Olimexino STM32/Maple?
To allow more flexibility for projects, I'd suggest taking all the CPLD's I/O pins [not going to the Arduino Uno], out the back edge of the board on a .1" pitch multi-row female [RA] header so they can be readily accessed. Jumper wires could be run to either breadboards or back into the shield pins to bypass the voltage translators.
I'm not so sure many USB ports can output 500mA.
You may want to obtain a Olimexino STM32 and make it part of your testing/verification methodology, and put that on your web site, although I'm not sure what volume of sales they have. Olimexino STM32 is sold on Mouser. Maple has multiple smaller distributors.
I have put your product number out in the Maple and Olimexino STM32 forums, so hopefully the web-crawlers will allow your product to be more easily found. I see a web-crawler already hit my post on the Olimex site.
...just food for thought...

EPT_User
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Post Re: Olimexino compatible?
on: May 30, 2013, 07:53
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Hi brucemellen, I have updated the schematic with Do Not Installs by the parts that are not installed and a Bill Of Materials. The schematic is available on the EPT-570-AP-U2 product page. Also, the User Manual has been updated to make the software installation a little more clear.

You raise some good points. We had debated about how to handle the power sharing between Arduino, EPT-570-AP and FT2232 Mini Module. The header idea lost out due to the thought that we want to get beginners attracted to the idea of designing and troubleshooting Programmable Logic Devices. And they might not be clear on how to insert the jumpers in the right spot or they might lose them. So, we figured just put large pads down and let the advanced people solder in 0 Ohm resistors in for different power configurations. We will definitely re-think this for the next design.

You are correct, there are other devices that can handle +5V and +3.3V I/O's. The Altera EPM1270 and EPM2210 can be easily designed to handle +5V on Bank 3 of their I/O's. The only problem, the cost per board will rise if we use one of these two devices. We stuck with the EPM570 because we can get it cheaply and keep the overall board cost low. We believe the low cost is the most important aspect for Arduino users. The goal for the EPT-570-AP was to produce a complete product that included a programming chip, CPLD, high speed clock, Arduino compatible I/O's and step by step instructions to produce advanced projects.

Our next product could include one of the larger CPLD's and a high speed bus that has its own high density board to board connector. This connector will be used to transfer high speed images from camera to a wi-fi chip. This would allow full motion video to be transmitted wirelessly from an Arduino robot.

brucemelle-
n
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Post Re: Olimexino compatible?
on: May 30, 2013, 16:48
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Response:
Thanks for adding/updating...
* It is not clear on the site whether the FT2232H mini-module is included in the development system purchase. Is it from FTDI or did you make your own?
* For your team discussion regarding the next board rev: I would never want to obtain/solder/desolder/solder/desolder... resistors on a board which will do many projects. Just print on the board the positions for power by the mini-module vs Arduino for the two different voltages (two strings of 3 pins w/2 shunts, shipped set for mini-module power). They shouldn't lose the shunts as they should set be one way or the other. If they (I) am trying to learn CPLD, then we should know enough about jumpers and power and understand a couple sentences in the documentation. I consider myself your typical beginner hobbyist, equally inept at hardware and software, having taken three analog/digital community college courses and done programming before you were likely born.
* I'm suggesting either a cheap 2nd CPLD dedicated to translation or chip translators that will also do 3.3V to 3.3V, leaving the development CPLD as-is. Wouldn't the cost be almost a wash replacing the $0.75-$1 x three sn74lvc4245apwr ?
* On the next board rev you may want to consider using a lower value resistor for R18-R21 so that it will be more visible with 3.3V supply and not toast with 5V, or move the LEDs to 3.3V
* On the next rev of this board you should consider adding two right angle PPTC102LJBN-RC and PPTC082LJBN-RC to the ends (or sides), to offer all pins not otherwise accessible.

brucemelle-
n
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Post Re: Olimexino compatible?
on: May 30, 2013, 21:07
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And don't forget about the Arduino Due and Netduino along with the Olimexino STM32 and Maple. Maybe a similar product to the EPT-570-AP-U2 with more flexibility would make sense, trading the translators for some additional connectors and jumpers. I'm not sure why, other than product momentum and install base, anyone would want an old ATmega processor or 5V.
Personally, for one of the supplemental external connectors, I'd like to see one side edge of the shield, with the 'ino and FTDI mini-module all together, plug directly into a standard breadboard like http://users.ece.utexas.edu/~valvano/EE345L/Labs/Fall2011/LM3S1968soldering.pdf,. You could get 48 pins or more directly into a breadboard in this way. Or at least make the holes in the shield so the developer could buy/solder the RA .1 pitch headers.
It could be the EPT-570-AP-D3 and almost a clone of the EPT-570-AP-U2.

EPT_User
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Post Re: Olimexino compatible?
on: May 31, 2013, 15:02
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Ah yes, great suggestion! The Altera EPT3032 can handle 5V and 3.3V on all I/O's. It has 34 user I/O's and is about $1 in quantities. I would have to put into the JTAG chain so that the user could change the pin types and add gates.

The FT2232H Mini Module is included in the EPT-570-AP-U2 package. I will clarify this on the product page.

I like your suggestions for building a product to support the Olimexino and Maple. I will purchase a Maple board this week and see what is involved in testing a CPLD product for this board. Designing and building a board is relatively quick (possibly two weeks), however testing and verification can take some time. I will let you know how it goes.

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