Using USB-8451 device to drive two i2c busses

Is it possible to use a single USB-8451 device to drive two seperate i2c busses at the same time or do I need to get a second 8451

I believe these devices act as single bus controller and if you want to control two separate buses, get two devices. An alternative (depending on the scope of your application) would be to use an FPGA device to implement as many controllers as you require.
Hope this helps.
StuartR

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Using USB-8451, and AD7747 from Analog Devices to measure capacitance and convert the capacitance to digital output

Hello,
I am new to LabView and data aqusition. I have LabView 8.5.1 installed on my laptop, and I studied the Getting Started document of LabView, except the data aqusition chapter.
I have microfabricated a differential capacitive sensor, and now I want to test the capabilities of my sensor.
After asking NI engineers, I have been suggested to use USB-8451 with AD7747 (24-Bit Capacitance-to-Digital Converter) from Analog Devices because AD7747 has I2C serial interface.
I have ordered USB-8451, AD7747, and Evaluation Board for AD7747. And I am waiting for them.
Are there any suggestions about how to connect my differential capacitive sensor to AD7747, and eventually to USB-8451?
You may want to know some further information to answer my question:
*The sensor is similar to the sensor on pages 501, 514, and 515 of "Microsystem Design" book from author Stephen D. Senturia.
*The datasheet for AD7747 can be reached from this link: http://www.analog.com/static/imported-files/data_sheets/AD7747.pdf
*My purpose is to make a very precise and accurate "displacement measurement micodevice" by using "the change in the capacitance" during the motion of the mobile fingers of the sensor.
As an initial challenge for myself, I will feel satisfied if I can measure the capacitance change in my sensor when I apply an external mechanical disturbance to my sensor. For example, there must be a change in capacitance if I just swing my hand from top of the sensor region.
I am looking forward for your reply,
Thanks in advance,
Sincerely,
sriverfxtr

Hi Aaron,
Here you go, this is made with a USB-8452.
When you run the code tick the power en dac enable box on.
Maybe you can help me with my problem, I want to use a fiber to sense light from a led.
Do you use any fiber hardware with the TCS3414?
gr,
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TCS3414.vi ‏63 KB

Using USB-8451 for accessing SMB Slave

Can i use the following example to read a SMB(System Management Bus) slave device using USB-8451 (since SMB is derived from I2C) .
Hardware Input and Output > I2C and SPI > I2C Basic > Generate I2C Read.vi
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The following is the read and write sequence examples , I want to confirm that this sequence is done by General I2C Read.vi .
Example Write sequence:
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6)      Data Byte 3
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1)      Slave Address 0x58
2)      Register Address 0x00
3)      Repeat start Slave address (will be 0x59)
4)      Byte Count 0x03 ( to read 3 bytes)
5)      Data Byte 1
6)      Data Byte 2
7)      Data Byte 3
Thanks
Baburaj

How to use USB Flash Key Pen Drive in Sun Ray?

Hello gentlemen,
Can anyone help me witn USB Flash Key Pen Drive in Sun Ray?
Every Sun Ray appliance has USB-ports and ammount of them more than default USB-set: Keyboard+mouse.
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I would like to connect a real USB GPS device to the emulator running my code. Is there any way for my app running under the emulator to access the real usb gps device? I did a search on this and did not find any relevant discussions.
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Thank you for your reply. But I can not connect the property node which you suggest me in reply of my question because there is problem of connection. Here I am attaching my vi so can you please give me the solution of my question, How can I use USB RAW device in Interrupt transfer write mode??
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project_basic1.vi ‏16 KB

Need help - I2C write/read with TAOS TCS3414 light sensor using USB-8451

Hello, I'm new to labview and need help setting up a vi that will allow me to communicate with a digital light sensor (TAOS TCS3414) using a USB-8451. I need to use the sensor to measure light from a light source that I designed and built as part of a project im working on. I've tried looking at several labview I2C exampled but find them to be very confusing. I've used an arduino to interface with the sensor successfully but need to use labview and dont understand how to write the program. The actions are simple; I need initialize the sensor with a simple command and then request data from 8 data registers and then read that data. The data will then be used in further calculations. The portion i need help with is writing and reading from the sensor. I've attached the datasheet for the sensor as a guide. I can also provide the arduino code that i use to read data from the sensor if that would help.
Pleae keep in mind that i am completely new to labVIEW. I really do want to learn from this but need quick results so the more help the better. It would greately appreciate any help or explaination.
Attachments:
TCS3414_Datasheet_EN_v1.pdf ‏1806 KB

Hi Aaron,
Here you go, this is made with a USB-8452.
When you run the code tick the power en dac enable box on.
Maybe you can help me with my problem, I want to use a fiber to sense light from a led.
Do you use any fiber hardware with the TCS3414?
gr,
Attachments:
TCS3414.vi ‏63 KB

Using USB 6341 device for frequency generation but level is droped when conect

i am using USB-6341 Daq Device for frequency generation. The desired frequency is generated correctly but when i connect to other device the voltage level i means the Peak to Peak voltage of the frequency dropped to 0.6, 1 Volt and also the frequency fluctuated. As I disconnect it from the load or the device the frequency becomes constant and peak to peak voltage becomes 5.
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Best Regards
Naseeb
Solved!
Go to Solution.

Hi Nasib,
I just wanted to clarify a few more things. Can you answer the following questions?
What frequency are you trying to generate?
When there is no load connected do you see the desired frequency?
When the load is connected, does the frequency always change to the same value or does it fluctuate within a certain range? If it fluctuates, what is the range?
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Using USB storage devices very slow in SL

I have two MAC's and use Entourage on both, in order to keep my Microsoft Data Base sync's I have it on a removable storage device which I move from MAc to Mac. Since updating to 10.6.1(SL) Entourage has slowed down to a snails pace and I can only assume that SL is doing something different in handling the USB external storage devices .
Very disappointing and frustrating .....Apple not a good move
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Yes, there are many threads about slow usb transfer or slow i/o in general e.g. (not necessary linux 3-related)
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Was the issue present in kernel26 as well? What filesystem does your usb device have? How slow is the transfer?
Last edited by karol (2011-11-19 15:30:59)

Mixed message lengths on CAN Bus using USB-8473 Device

I am attempting to use the Frame API functions for LabVIEW
and send both 11-bit and 29-bit headers over a bus that uses both address lengths. I am currently successfully sending 11-bit
packets but the 29-bit packets are having their addressing truncated to the 11-bit
length when put on the bus.
As far as I can see I should have to set the standard
comparator to 0xCFFFFFFFF and then send messages. I am using a NI USB-8473 CAN Device for doing
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You need to OR your Extended ID with the 0x20000000 before giving it to the NCwriteNet.vi.
This is the way that the underlying CAN driver and hardware know that is it an extended ID you are trying to send.
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Why do I get error -301703 on a USB-8451 device?

Hello,
I'm not very familiar with LabView.
I 'm trying to use USB8451 to program an Atmel microcontroller (using SPI).
I write 8 bytes at time, without any problem, but I get error -301703 when I write the following 8 bytes:
0x40 0x00 0x19 0x03 0x48 0x00 0x19 0x00
I tried to reduce the clock rate (from 2M to 200k), but without any effect. I don't know if this can be related on the contents of data written: however the error always occur with these data.
The error occur on the "NI-845x SPI Script Write read. vi:1"
Can someone help me?
Thank you
baloss

Hello Matthieu,
thank you for your suggestion. I tried to write more scripts in sequence. But in fact it didn't work as expected.
My idea was to erase the contents of the script when the limit of 64 instruction was reached, and then fill it again.
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Best Regards
baloss

Usb-8451 i2c developement

Generated a simple program to talk to i2c on NSE5310 using usb-8451. I get the following error.
Error -301742 occurred at NI-845x I2C Write Read.vi:1
Possible reason(s):
NI-845x: The slave did not acknowledge an address+direction byte transmitted by the I2C master. Reasons include the incorrect address set in the I2C configuration or the incorrect use of the 7-bit address. When entering an address to access a 7-bit device, do not include the direction bit. The NI-845x Basic I2C API internally sets the direction bit to the correct value, depending on the function (write or read). If your datasheet specfies the 7-bit device address as a byte, discard the direction bit (bit 0) and right-shift the byte value by one to create the 7-bit address.
I do have pullup resistors of 1.5k on both SDA and SCL. I've attached the data sheet for the device and a sample program.
THANKS FOR YOUR TIME. Happy Holidays.............................
Attachments:
NI-8451 Testing ver2.vi ‏13 KB
NSE-5310_Datasheet_v1_0.pdf ‏1569 KB

You are providing the wrong address. As the error message says, you must provide the 7-bit address, excluding the read/write bit. . You are providing the full value of the first byte, including the read/write bit. In other words, you are doing the exact opposite of what the error message tells you to do. If you've set the user-bits to 0 then the correct address is 0x40.
Side-note: When you set a front panel numeric control to hex display you should also display the radix so that others know that it refers to "81" hex, and not "81" decimal, which are two different values.

Integrating an NI-USB 8451 driver and Labview Run-Time Files in an installation package of a .vi application

Hello,
I've built a .vi which uses the NI-USB 8451 device (please see http://sine.ni.com/nips/cds/view/p/lang/en/nid/202368), and I would like to create an installation package to be used on a costumer's PC, which has no Labview installed on or a driver for this device.
I would like to have this installation as a completely stand-alone setup, so that the user could take this file and run it, and have the driver to the 8451, the run-time files for the Labview application installed by themselves, and have the .exe file working on a completely "clean" PC.
How can I integrate it all in one package ?
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Michael.

Nice hearing from you again, Ipshita
I do not call any dll's currently, but am using the driver of the USB device, NI-USB 845x, version 1.0.1
Now, I would very like to make the use of my application, by another user, with no Labview or this driver on his PC, as simple as possible.
I just thought that maybe I could create an .EXE file with some Labview created dll's, which this executable would use, and spare the need of the 845x Driver or Labview Run-Time library prior installation. I could be wrong.
What should I do ?
P.S.
Meanwhile, I've been playing with the Application Builder and tried to create an installation with the Driver and the Labview Run-Time.
It had started the compile, but stopped with the following pop-up window: "Locate the 'NI-845x Software 1.0.1' distribution. Labview needs to copy a component installed or updated by the distribution..."
(Attaching the pop-up window below)
What is it looking for and where can I find it ?
Thanks,
Michael.
Attachments:
Installation_pop-up.JPG ‏20 KB

USB-8451 SPI interface with analog devices isensor

Does anyone has example VI using USB-8451 with analog devices isensor? I am new to SPI interface and very slowly learning how to use labview in conjunction with USB-8451 to do SPI sensor reading.
Any help would be appreciated. I'm using labview 8.5.

elpiar wrote:
It's working!
Well, I realized I made a small mistake in the example. The number of bytes in the array constant should be 4, not 2. The device is full duplex, meaning you can write and read from it at the same time. The NI-845x SPI Write Read VI returns the same number of bytes as the number of bytes that were written. Thus, with just 2 bytes you will not actually get the current value of the register. You would get the values from the previous command. See attached mod.
Now if I read the data is burst mode, will the output be automatically be arranged in an array of 8-bit length words? You mention something about send out out 8 clock burst. I'm not sure how I do this.
For burst mode you have to send out more bytes so you get clocks generated for the read to occur. The burst mode command is 3E00. That needs to be followed by 12 16-bit numbers for the device to return all the registers from SUPPLY_OUT to AUX_ADC. The actual bytes after the 3E00 are irrelevant for a write. The NI-845x SPI Write Read VI should then return 26 bytes (2 bytes that line up with the 3E00 command, followed by 2 bytes per register, for 12 registers). You can convert this into an array of U16 values and do the conversions based on which register you're actually reading. I've attached a VI to get you started. The example converts the SUPPLY_OUT register and each of the GYRO_OUT registers. You can finish the VI. Note that you should make the 14-bit to 16-bit extension a subVI so you're not duplicating code.
NOTE: As with all example code that is provided you should verify that the numbers you get are correct. We don't have the hardware, so we can't verify correct operation.
Attachments:
ADIS16400 XGYRO_OUT v2.vi ‏29 KB
ADIS16400 Burst Read Example.vi ‏36 KB

Pls help! USB Storage Devices does not work for K7N2 Delta-L

hi all,
I am pulling my hair out trying to resolve this issue.
Everytime i plug in a USB Storage Device/Thumb Drive(eg Creative NOMAD), my system gives an error saying task cannot be performed due to a I/O device error.
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Thanks!
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I'm pretty much going to confirm the same going with compatibility issues here...there is still alot of hardware out there on the market that is incompatible with many other types of hardware...
We've reached the day when alot of us like to think that ALL manufacturer devices should work flawlessly with everyone else's devices on the market. This just isn't the case and I don't ever see this being the case. Ideally it would be nice but the fact is is that no company can "cover all the bases" in this respect. There are literally hundreds of thousands of hardware mfg's out there now and this cannot be a reality unless the PC world goes Apple. Same standards for all period. No fluctuation or ability to expand on new ideas without going to the "Standard Setting Company" directly for full testing capability.
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USB 8451-how to set a chip select value

I need some help on USB-8451 SPI programming using LabVIEW. On the USB-8451 device, there are 8 physical chip select (CS) lines. I will need to program or use all of these CS lines to select one of the 13 SPI slave chips on the circuit board. I know I will have to use the SPI Configuration Property Node to program CS state. What value should I use to set the CS property if need the following CS line states to select one of our chips?
CS0 = 1; CS1 = 0; CS2 = 0; CS3 = 1; CS4 = 1; CS5 = 0; CS6 = 1; CS7 = 0
Thanks, Min.

FYI: VI referenced is attached.
Chris R.
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National Instruments
Attachments:
845x CS Lines Set_modified.vi ‏28 KB

Using USB-8451 device to drive two i2c busses

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