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I'm surprised they isolated the USB rather than the serial lines.
Not too sure why Arduino seems so hated. It is pretty slow compared to higher end stuff like ARM and dsPIC, but it still has a place. -
I'm surprised they isolated the USB rather than the serial lines.
LT sell these nice modules that have a DC-DC converter and isolator in the one small package. I've used their RS485 version before. Looks like this USB isolator is a new version that they'll release to the greater unwashed at some stage.
Only downside is they're many times the cost of other solutions.QuoteNot too sure why Arduino seems so hated. It is pretty slow compared to higher end stuff like ARM and dsPIC, but it still has a place.
I'm not sure it really is. It seems that uC topics like this that have no single technical answer just attract a disproportionate level of emotive involvement. Just go and have a look at the "why would you use an 8bit uC" thread. That thread spans hundreds of posts and multiple years, yet it has to be one of the technically least interesting topics that gets brought up on this forum. Such is the beast of the internet. -
Never mind the uC hi-class nerds. Soon their GHz processors will be just as 'heritage' as building-sized computers from the 1960's...
LT has isolation uModules - and AD and Microchip and others also. I can always buy a part and build something. But I am a board collector. I don't care about broads - give me boards ...
Anyway - I now probably have the world's first Linduino-Protocol-Hardware-Emulator Shield for Arduino. Two CD4051 (pin A switches I/O nos. 0 and 1). This has the exact same electrical function as the original dual SPDT switches in the FSA2257 in the schematic.
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My "Linduino clone" Multiplexed I2C / SPI Arduino works fine. I will build a permanent shield. My best option for isolation so far seems to be ADuM3180/4180 (fleabay USD15-20 inc. postage). Any other ideas (isolated ground/power+data)?
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The original on-board LTM2884 must be
something like
http://www.linear.com/product/LTM2881
http://www.linear.com/product/LTM2882
http://www.linear.com/product/LTM2883 -
For those who have read about the Linduino and taken a look at the schematic/C++ library, you will have noticed that the board has 3 serial buses on 2 wire sets : auxiliary I2C (hardware I2C) for the EEPROM board identification / calibration data storage chip, data SPI (muxed to hardware SPI), and data I2C (muxed to hardware SPI).
I made my first clone using two CD4051 (pin A switches I/O nos. 0 and 1). This has the exact same electrical function as the original dual SPDT switches in the FSA2257 in the schematic. Later I have found out that all I need is 1 pcs. CD4066.
At first the onboard EEPROM on LTC's ADC and DAC evaluation boards was an annoyance to me. Later I have understood how useful it can be to store data along with the chip.
It seems I am not the only one. A quick search gives many links and is in general covered by this:
EEPROM memory is used to enable features in other types of products that are not strictly memory products. Products such as real-time clocks, digital potentiometers, digital temperature sensors, among others, may have small amounts of EEPROM to store calibration information or other data that needs to be available in the event of power loss. http://en.wikipedia.org/wiki/EEPROM
There is even a video on the theme (see end of post).
The Linduino has the LTSketchBook library with easy to copy code and menus like this:
Code: [Select]Serial.println(F("\nCommand Summary:"));
Serial.println(F(" 1-Write to input register (no update)"));
Serial.println(F(" 2-Write and update DAC"));
Serial.println(F(" 3-Update / power up DAC"));
Serial.println(F(" 4-Power down DAC"));
Serial.println(F(" 5-Set reference mode"));
Serial.println(F(" 6-Calibrate DAC"));
Serial.println(F(" 7-Enable / Disable calibration"));
Serial.println("\nPresent Values:");
Serial.print(" DAC Reference: ");
if (reference_mode == REF_INTERNAL)
Serial.println("Internal");
else
{
Serial.print(F("External "));
Serial.print(reference_voltage, 5);
Serial.println(F("V reference, please verify"));
Serial.print(F("Enter a command:"));
So now I will add a 32k EEPROM to my best voltage reference boards. I will be able to store date of measurement, instrument and range used, PSU, temp, humidity and measured value in around 15-20 bytes (if I am not wrong). That means I can store a thousand or two thousand measurements on one 32k chip. Has anyone any experience with long time use of DIY or purchased devices with EEPROM calibration values or data?
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LT has posted a video about this Linduino on youtube:
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Quote
LT has posted a video about this Linduino on youtube:
I like his smile.
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Oh good lord. You guys weren't supposed to see this... ever.
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The video is good and so is the board / library. But the thumbnails are the prize we pay for digitally stored videos. You can just have somebody change it.
BTW
If you want to keep this thread alive, please help by posting. I think some insider reports from LTC would make good reading ... -
Well as far as insider stuff goes.
Right now we're working hard trying to fill in a back log of parts that we do not have code for. I'm also working on a short article/tutorial on how to convert our library code into a fully functioning data logger along with the code for a simple Windows based GUI to control the data logger.
If anybody has requests for certain parts that they want code support for, well please let me know. Right now our first goal is to cover most of the popular Delta Sigmas. We also plan on having code support ready whenever a new part rolls out. -
What I would really like is if LTC made a pro GUI with open code. I have seen your PScope and LTPowerplay. Fancy software.
Did you now that Microchip publishes the full code for their DataView.
http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1406&dDocName=en024782
Make a template for DIY GUI's for Linduino like the MakerPlot or something similar in C++. Many people will thank LTC for it.
(FYI MakerPlot is cheap and good, but no code
)
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The problem with giving people code is it often costs more in man hours for us to support than it would if we just dealt with it on a case by case basis.
If you dig into the DC590B emulator code, you'll begin to realize why. We have a serial protocol in place, and a lot of the code inside of QuickEval or PowerPlay ends up being obtuse strings such as: MIsS98S85sS99QQQQRp or something along those lines.
So people who dig into our GUI code not only have to deal with learning how the loop works, but then need to learn our "T++" (internal nickname for it) protocol and we end up burning more time explaining it.
But, that's why we started Linduino. Sure it's not a GUI, but it's easily explainable and transferable across multiple platforms. -
Well ... I finally managed to get my hands on a real Linduino. Thanks a lot to LTC.
So now I have two - that is - the second one (my Linduino-Emulator shield for Arduino) is only digitally function compatible (no USB isolation).
I have put he new Linduino to test use: 18 Bit DAC (LTC2756) to 24 Bit ADC (LTC2400) Loop Back.
The DAC is connected to PC via Linduino to USB. The DAC outputs the voltage that is chosen in QuikEval software.
The ADC voltage is measured by the ADC. The ADC is connected to PC via Arduino w/ the Linduino-clone shield to another USB port.
A DIY GUI Java applet (just a barebone start) made in Processing receives the ADC data and outputs them to screen.
When I have made an input field for the DAC voltage in the Java GUI (and drops QuikEval alltogether), I will incorporate both Linduinos (com x and y) to the same running program. Next step is to also measure the DAC output voltage with the 34401A and output the RS232 measurement to a third Arduino on com z. All three datasets - the DAC setting, the ADC reading and the DMM reading - are then accessible in the same program.
So I will be able to do:
But TTT (Things Take Time ...)
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Hi,
Any updates on the Arduino version of Linduino ?
I've tried to download the DC590B on an arduino UNO and try to connect to QuikEval PC software.
I end up with "The USB-to-Serial Controller is not connected" message.
I guess this may be a USB driver problem and not related to the actual arduino software.
A tutorial from someone that has succeeded whould be nice :-)
Or maybe I have to buy the Linduino to save some time (not money...)...
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After using processing to display a graph of the of the ADC readings via an Arduino, I can only second what Helgel has asked.
Is it feasible to use QuikEval with a normal Arduino and a homebrew LTC ADC board?
Greetings
Hannes -
Hi,
Any updates on the Arduino version of Linduino ?
I've tried to download the DC590B on an arduino UNO and try to connect to QuikEval PC software.
I end up with "The USB-to-Serial Controller is not connected" message.
I guess this may be a USB driver problem and not related to the actual arduino software.
A tutorial from someone that has succeeded whould be nice :-)
Or maybe I have to buy the Linduino to save some time (not money...)...
Hi,
One of the differences between a Linduino and Arduino UNO is that Linduino uses an FTDI chip for USB to serial data conversion, while Arduino has a different ATMEL chip. QuikEval software is programmed to to look for the FTDI chip and it would not work on an Arduino UNO. However, if you are trying to simply talk to some LTC part, we have code libraries that would work on an Arduino (with a few changes to the Linduino code). Hope this helps! -
Hi,
Any updates on the Arduino version of Linduino ?
I've tried to download the DC590B on an arduino UNO and try to connect to QuikEval PC software.
I end up with "The USB-to-Serial Controller is not connected" message.
I guess this may be a USB driver problem and not related to the actual arduino software.
A tutorial from someone that has succeeded whould be nice :-)
Or maybe I have to buy the Linduino to save some time (not money...)...
Hi,
One of the differences between a Linduino and Arduino UNO is that Linduino uses an FTDI chip for USB to serial data conversion, while Arduino has a different ATMEL chip. QuikEval software is programmed to to look for the FTDI chip and it would not work on an Arduino UNO. However, if you are trying to simply talk to some LTC part, we have code libraries that would work on an Arduino (with a few changes to the Linduino code). Hope this helps!
An alternative if you have an Uno and FTDI cable laying around may be to just hook the cable up to the UART pins so the onboard USB converter is bypassed!LinguiniLinduino, could I contact you about getting a Linduino and possibly one or two evaluation boards for an OSH project I'm working on? It would save me so much time versus rigging up my own test jigs. (This project will be going into small scale production later this year.)
Sent from my Tablet -
Sure! I would be happy to help. Email me at linduino@linear.com.
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Since I am the one who started this topic - sorry for not following it up (health reasons, I do not read or post anywhere anymore) .
Hello to Leo and all. I still use the Linduino that LT kindly gave me. It is a very good board with USB ground isolation and clean power, and has excellent free code. I also use the clone that I built myself (see earlier posts and video).
I am a bit sorry that Linduino has not taken off in the Arduino world, but as LT has stated: They do not want to set a price that competes with Arduino and clones. Fair enough. LT is not a sandbox player but a professional business.
Du to reasons stated above, I have had little chance to work with electronics. However, if anyone wants to make a Linduino clone from an Arduino, it is quite easily done. But you must read my earlier posts about MULTIPLEXING OF I2C AND SPI.
On page 11, Block Diagram in
http://cds.linear.com/docs/en/demo-board-manual/DC2026AFB.PDF
you will see that there is a multiplexer. You will have to reproduce this MUX or it's function. On page 14 you will see the schematic with the Atmega processor U7 and the MUX chip U4. This is the MUX you will have to buy, or emulate its switching by using junk box logic (as I have written in earlier posts). You can mount the MUX and the other components around it on an empty Arduino shield.
Now look at the schematic
http://cds.linear.com/image/resized/934asch.jpg from http://www.linear.com/solutions/3305.
You will see that the board has an a DAC, an ADC, a MUX and an EEPROM.
The WIRED Arduino I2C is OCCUPIED by the EEPROM. The DAC and ADC shares Arduino SPI via the MUX. The resultant signal is DEMULIPLEXED in the earlier mentioned Linduino MUX. So there are two MUXes - one for mixing the signals on the DAC/ADC board, and one for separating them before they reach the Atmega on the Linduino board.
So, unless you understand what I have just said, you will in my opinion find it difficult to use an Arduino as a Linduino clone.
OK. That's it. I am sorry I cannot follow this up. I highly recommend the Linduino and the code Library, and hope more people will use it. Thanks again to LT for generous help. -
I'm a bit confused, but let me see if I have understood this:
1. Linduino uses an FTDI chip for USB to serial data conversion. Thus, QuickEval will not detect the UNO. That could be fixed by "bypassing the onboard USB controller" with a "FTDI cable" as indicated by Timb. Can someone explain how that is done ? Are there other alternatives ? What about modifying the QuickEval ?
2. There is a MUX on the Linduino that is used to "detect" the various ADC/DAC modules. This can be fixed by the hardware modification described by Quantumvolt. But is it also correct that it can (instead) be fixed by modifying the arduino code as described by Linduino in this post: http://www.linear.com/solutions/4537. Or are these different things ?
3. The Linduino has USB optoisolation. I guess this is not vital, except for noise, measurement accuracy etc.
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What about using Arduino Nano with FTDI for this kind of emulation?
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I briefly tried with an Arduino Pro Mini with the following FTDI based USB to TTL Serial Cable: http://www.ebay.com/itm/400356015296?_trksid=p2059210.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT.
No success, though I didn't try very hard... -
I'm a bit confused, but let me see if I have understood this:
1. Linduino uses an FTDI chip for USB to serial data conversion. Thus, QuickEval will not detect the UNO. That could be fixed by "bypassing the onboard USB controller" with a "FTDI cable" as indicated by Timb. Can someone explain how that is done ? Are there other alternatives ? What about modifying the QuickEval ?
2. There is a MUX on the Linduino that is used to "detect" the various ADC/DAC modules. This can be fixed by the hardware modification described by Quantumvolt. But is it also correct that it can (instead) be fixed by modifying the arduino code as described by Linduino in this post: http://www.linear.com/solutions/4537. Or are these different things ?
3. The Linduino has USB optoisolation. I guess this is not vital, except for noise, measurement accuracy etc.
It really is very simple.
If you must use QuikEval you have to emulate Linduino and any supported LT demo board. This involves USB 'handshake'-ing to Linduino and (flat cable) read from Linduino of the signature of the EEPROM on the connected demo board. Leo now also says that QuikEval looks for FTDI stamp.
Dropping QuikEval you can:
Use any I2C exclusive-or SPI demo board (LT original or DIY) with ANY Arduino (as Leo explains in the link you give yourself). Effectively you just set the bus to EITHER I2C or SPI, and throw out the code that Linduino uses for checking that a demo board is connected. [This is a totally different case from the following:]
If your board uses BOTH SPI and I2C (like I2C DAC and SPI ADC - see for instance LT Demo Board DC934A - http://www.linear.com/solutions/3305), LT's Linduino code will work ONLY IF you make the hardware mods I have described. Any Arduino is OK. But still you might/will not be able to use QuikEval.
The ground isolation is totally irrelevant to all these considerations. It is just a nice feature to avoid (potentially harmful) ground currents.
[Edit: DC943Ato DC934A. Added link]
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@quantumvolt
I have LTC2983 demo board. But i don't have a Linduino board. I want to use my demo board with Arduino. QuickEval is not necessary now. I just want to read temperature datas from LTC2983. Can i use LTSketchbook examples for this demo board directly? or do i need some modification because of MUX? -
I guess the 'LTC2983 demo board' is DC2296 http://cds.linear.com/docs/en/demo-board-manual/dc2296fa.pdf.
First - from the LTC2983 datasheet http://cds.linear.com/docs/en/datasheet/2983fc.pdf - the chip is an SPI device.
Secondly - from the DEMO MANUAL DC2296 (top link) schematic on page 21 there is NO I2C device on the board. So I quote myself from my last post over:
"Dropping QuikEval you can:
Use any I2C exclusive-or SPI demo board (LT original or DIY) with ANY Arduino (as Leo explains in the link you give yourself). Effectively you just set the bus to EITHER I2C or SPI, and throw out the code that Linduino uses for checking that a demo board is connected."
So - as you are NOT using QuikEval AND the board is EXCLUSIVELY SPI you can use ANY Arduino. All you must be able to do is to talk to U1 in the schematic for the demo board [CS(bar), SCK, MOSI, MISO on J2]. You can use Linduino code and forget everything about the U2 EEPROM chip I2C stuff (which is just for QuikEval identification of the board).
LTC explains how to change the Linduino code in 'Going Generic' (= using Arduino) here http://www.linear.com/solutions/4537. But you really do not need the Linduino code - your board is nothing but another SPI chip - so any Arduino SPI tutorial or example program does the trick. However - the Linduino code will have the right data formats in the right sequence already.
Also there seems to be some LTC software that generates C-code to configure, program and run the LTC2983 device http://cds.linear.com/docs/en/software-and-simulation/2983dsmf.pdf.
So this is what I would do:
1. Learn Arduino SPI.
2. Modify Linduino code for LTC2983 to run on Arduino.
3. Run the LTC2983DSM and cut and paste what you need / want for your number of channels and sensor types and whatever other options there might be.
Good luck. It is not difficult - just a lot of work.
PS (Your PM). If you want to build a Linduino clone you must study the Linduino schematic http://cds.linear.com/docs/en/demo-board-manual/DC2026CFD.PDF. You will see that Linduino=Arduino+Mux+PullUpResistors+OtherResistors+Capacitors+.... Then you take an Arduino and put the rest on an empty shield and draw some wires. Voila - you have a Linduino