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CC1310: Internal/External bias and "ambient" RSSI measurements

March 29, 2018, 10:18 am
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Part Number:CC1310

We have measured "ambient" RSSI in an environment without any intentional radiators at our frequency using the LAUNCHXL-CC1310 and got back values in the range of -92 to -101. Those values seem reasonable to me, but I guess my first question is do those values make sense?

On a board of our own design (though largely based on TI references) using external bias we took the same measurement and got back values in the range of -83 to -89. If the values the LAUNCHXL-CC1310 gets back are reasonable, do the values we get with our board indicate a problem? I experimented with changing the value of the external bias inductor and it did influence the readings but I am not sure if I am messing something else up by doing that, or how I should determine the "correct" value.

Thanks for your assistance!

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ADS1115: How to get the right readings from ADS1115 for a voltage range -3 to 3 V?

March 29, 2018, 10:24 am
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Part Number:ADS1115

Dear sir,

I have a device that works in the voltage range -3 to 3 V, and I want to measure its IV curve, so I generate a voltage in this range using MSP430, RC filter and opamp that is used to convert the signal from unipolar to bipolar, now I applied this voltage to the device and I don not have any problem.

I know ADS1115 can not read a negative voltage so I convert back the readings of the device to a unipolar (using opamps) before connecting it to the ADS1115, my questions is how to return back the right readings from ADS1115?

Thank you

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LM15851EVM: NCO_x inputs connections

March 29, 2018, 10:43 am
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Part Number:LM15851EVM

Hi!


The LM15851 datasheet states that each NCO_x pair must be connected together and driven with a common 1.8V LVCMOS signal (but, as it's seen in the Pin Functions table, these inputs appear to have differential structure). In turn, in the LM15851EVM a single-ended connection to only one side of these differential inputs is made. A differential connection to these NCO_x inputs is made as well (exactly as it's made for DSx outputs). It's a bit confusing.

Can you give some explanations on why you connected to the NCO_x inputs in such a way? Why didn't you do it as the datasheet requires?

Thanks in advance.

Regards, Vic.

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CC2538: PANID and extendedPANID manipulation

March 29, 2018, 10:43 am
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Part Number:CC2538

I experimented that I want to form one network use NLME_NetworkFormationRequest(). Furthermore, I want to form the network with PANID and extended PANID as the parameters I set myself, but not random number. Right now it does not work,

Can I change the PANID and ExtendedPANID by some API? Or how can the NetworkFormationRequest() form the network as the PANID and extendedPANID as I set?

Best Regards

 Xian Wang

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LM5118: LM5118

March 29, 2018, 11:00 am
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Part Number:LM5118

Limit current to pins on LM5118 so smaller creepage rules can be used. 

Vin = 9V to 40V.  Vout = 12V, Iout = 2A.

I would like to limit the current going to certain pins on the LM5118 to allow for the small spacing between pins on the device.

The pins that appear to be a concern are Vin, Vout and HS.

For Vout I would like to put a 500 ohm resistor in series.  I am not sure what the current over the resistor will be and how this may affect the emulated current mode.

For HS I would like to put a 500 ohm resistor in series.  This appears to be a reference for the high side gate driver. Are their any concerns with adding resistance here?

For Vout I would like to put a 200 ohm resistor in series.  Datasheet shows a current of 40mA on this pin.  This would result in significant voltage drop.  Perhaps for this pin an LDO with current limiting could be used.

Could you please provide feedback on the above pins and the affect the series components might have?

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DS90CR485: My design is not working as expected

March 29, 2018, 11:01 am
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Part Number:DS90CR485

Is Pin 24 DC balance working in this part, the datasheet Figure 12 is label as GND?

If I connect pin 23 low do I only get data from channels A0P, A0M, A1P, A1M, A2P, A2M and A3P and A3M on rising edge of the clockin? Is the output data corresponding to input pins TxIN0 (D0) to TxIN23 (D23)?

I found the schematic for the demo board where pins 26, 27, 54, 59, 60, 61, 62, 63, 64, 65, 66, 67, 78, 88 are not connected. Is it OK to leave those pins floating?

When VCC3 is connected to 3.3V can pre-emphasis pin be connected with 50 ohms to 3.3V?

Thanks a lot for your help.

Roberto

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LAUNCHXL-F28379D: Firmware Upgrade / Flash of C2000 Delfino via CAN

March 29, 2018, 11:05 am
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Part Number:LAUNCHXL-F28379D

Hi,

I am looking to flash C2000 Delfino via CAN using TM4C. Please suggest some standard method/api/tool, if any. Also guide me regarding safety checks and error checks to be done after the flash to check if the flash was successful.

With Regards,

Vedant

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SENSOR-CONTROLLER-STUDIO: sensor controller ram overflow - cc1350

March 29, 2018, 11:07 am
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Part Number:SENSOR-CONTROLLER-STUDIO

I'm building a SCS project to talk to a couple of i2c devices and am running up against a RAM overflow issue. Basically my code is too big and was wondering if there are any tricks or workarounds. I can probably trim the code and data to fit, but 1024 words seems pretty small. Is there any way to increase the space available or compiler option to optimize for size? The spec says its 2KB, so assuming 2 byte words, it looks like this is a hard limit.

The bulk of my code is in the initialization and configuration of the i2c devices. I'm thinking of doing 2 separate projects where I initialize the devices in one, then unload that project and swap in the running/data gathering project. Since the individual task in SCS is already split into this "general" model, it seems that there would already be a way to do this (i.e. only load the initialization, execution, or termination sections when needed, to save on RAM). Any thoughts?

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MSP430F5529: Programming MSP430F5529 via Spi-By-Wire

March 29, 2018, 11:21 am
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UCC24612: Proper Phasing for CM Balanced Flyback Transformer when using SR in return leg

March 29, 2018, 11:34 am
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Part Number:UCC24612

I am using a UCC28740 in combination with UCC24612 in the return leg of secondary side of transformer.  I am trying to implement a CM Balanced transformer design but i am not clear as to phasing when my SR is in the return leg. Application note titled "Flyback transformer design considerations for efficiency and EMI" states that special care needs to be taken when using Sr in the return leg while utilizing PSR regulation. Can i get a more clarification on how to properly phase the winding using the suggestions in this note.  I will attach an a schematic of an application with PSR and Diode in the positive leg.

Scott(Please visit the site to view this file)

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UCC28780: Design documents

March 29, 2018, 11:39 am
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Part Number:UCC28780

I started using the data sheet for this extremely complex part, section 8.2.2 "Detailed Design Procedure", and found by the end of the page that it was pretty much useless.  VCLAMP and VSPIKE are required to calculate turns ratio, and I couldn't find how to estimate them anywhere.  Then in 8.2.2.2.2 I read "KRES represents the duty cycle loss to wait for the switch-node voltage transition from the reflected output voltage to zero.  5% to 6% of KRES is used as a initial estimated value."  This seems to be a typo.  It makes no sense and doesn't give a clue to estimating KRES.  Then in eqn (23) at the bottom of the page I see where fSW(MIN) is required and no help anywhere for estimating it.

So by the end of just the first page of the procedure I was stymied and unable to calculate any of the variables.  No actual numbers (for example, for the EVM design) are shown for any of the equations in section 8.2.2, either, so you can't cross check the formulas or piece together what the variables mean.

Fortunately I found the Mathcad documents in sluc644 and I have Mathcad.  These are very helpful and look like they will make an actual design possible.  I have found a couple errors in "ACF Power Stage Calculations  - 21070531.xmcd" though:

  • The min and max NPS calculations can come out with min > max, depending on the input variables.  I have a high VBULK design, and I ended up with NPSmin = 7.265 and max = 5.302.  Then, I had to use an NPS of 5 (outside the given inverted range) in order to pass the VDS_margin test.  I think the worksheet needs more testing with wider input voltage range, and I'm not sure I'm getting the right turns ratio.
  • The calculation for kZmax is wrong if VBULK > VRfl.  I put a conditional test in there, but I'm not positive it's right.
  • I still can't find help anywhere on the required voltage rating for the clamp capacitor.

Please let me know if you want my edited copy of this worksheet so far.  The "insert file" button here doesn't look like it's working right.

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CC1310: CC1310 problem

March 29, 2018, 11:55 am
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Part Number:CC1310

Dear TI sir :

I would like to know the application of CC1310 :

1. On 802.15.4 SDK,   Dose it support 1M-bps data rate ?

   if it can, how to do it?

2. Dose  CC1310 support the frequency is at 783MHz ?

    if it can, how to do it?

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BQ25890: BQ25890 driver

March 29, 2018, 12:02 pm
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OPA381: Autozero operation - photoconductive mode TIA - single ended supply

March 29, 2018, 12:06 pm
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Part Number:OPA381

(Please visit the site to view this file)

I have run into a difficult to explain situation with the OPA381 in a simple TIA configuration with a photodiode in zero-bias photoconductive mode. The system is using a Thorlabs IS236A integrating sphere with an SM05PD1B photodiode. A 660nm red LED is being pulsed at 500Hz (500usec PW) at the input of the integrating sphere using the TI AFE4490 EVM. When the integrating sphere is completely closed with the LED at one input port and measuring the photodiode output, there are what appear to be ~100usec auto-zero glitches at the TIA input and output. Please see below:

 

 

In the following scope shot traces: Yellow = TIA inverting input, Green = TIA output

 

In this shot, sphere is open to ambient light @ one of the ports while measuring the RED LED – all seems normal . . .

 

 

In this shot, all integrating sphere ports are closed while measuring the red LED.  Yellow trace is TIA input and the voltage should always be zero (i.e. zero-bias action of op-amp summing junction).  In this case it looks like an autozero is performed that also glitches the output.  Not much detail on autozero in datasheet other than it is proprietary and takes about 100usec. From what I know about chopper stabilized amplifiers, the glitch at the input appears to be an autozero attempt.

 

 

This is very repeatable and seems to be related to the dark condition of a totally enclosed integrating sphere.

 

My questions are:

  1. Does it seem that this is an artifact of autozero operation?
  2. Am I required to use reverse bias as in figure 4 of the data sheet when operating from a single ended supply? Would this eliminate the glitch I am seeing here?

 

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CCS/TM4C123GH6PM: can't open a terminal

March 29, 2018, 12:19 pm
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Part Number:TM4C123GH6PM

Tool/software: Code Composer Studio

Hi all, 

I have used the terminal (serial monitoring) in CCS for debuggng many times before.

Yesterday, it stops working suddenly. I tried a lot to send data using this snippet

InitConsole(); 
uartprintf("Testing .. \n ");

but nothing works.

I have installed CCS v.8.. when i choose and open the com port the window appears with <closed> title ! 

any help ? 

Regards, 

Sarea

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Compiler: Issue with captures

March 29, 2018, 12:22 pm
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Tool/software: TI C/C++ Compiler

I am trying new c++ features not supported with the previous compiler and found and issue that I would like to ask about. The snippet is taken from Josuttis' "The C++ Standard Library", 2nd edition:

#include <iostream>

using namespace std;

int main( void )
{
    int x = 0, y = 42;

    auto qqq = [x, &y]
                {
                    cout << "x: " << x << endl;
                    cout << "y: " << y << endl;

                    ++y;
                };

    x = y = 77;

    qqq();
    qqq();

    cout << "Final y: " << y << endl;
}

It compiles properly, but when I try to debug it I get:

The project configuration is sane though, I can run it by removing the lambda and the local variables from main() and not using any capture argument:

#include <iostream>

using namespace std;

int x = 0, y = 42;

auto qqq = []
            {
                cout << "x: " << x << endl;
                cout << "y: " << y << endl;

                ++y;
            };

int main( void )
{
    x = y = 77;

    qqq();
    qqq();

    cout << "Final y: " << y << endl;
}

Gives:

Since the book is post c++11, is this something that changed with c++14?

Thank you,

Pibe

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CCS on MAC - few questions

March 29, 2018, 12:24 pm
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Hi team,

 

I don’t have any hands on experience with MAC, but had a customer bring up a few things. We have CCS support for MAC, but it seems Tivaware only has a windows executable. I think some have manually copied files, also one could use TiRex. Do we have a formal way to get Tivaware into CCS on MAC? For example in v7?

 

Also I thought TI-RTOS was part of the App Center? I don’t see TI-RTOS in my v7.2 install. I do see the older DSP/BIOS however. Is there an update site one can add to bring in TI-RTOS, short of going to its product page to download? Again this is for the MAC users.

 

Maybe its included in the App Center in v8?

 

Thanks in advance for the help,

Billy

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CCS/CC3200: Install TI-RTOS for SimpleLink from the CCS App Center

March 29, 2018, 12:28 pm
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Part Number:CC3200

Tool/software: Code Composer Studio

I have installed CCS 7.3 . 

I want to install TI_RTOS for Simplelink from CCS App Center so that I could exercise sample  projects. However I can not locate any TI-RTOS module  in the app center.

I installed tirtos_cc32xx_2_16_01_14 manually. If the CCS App center fails to locate TI-RTOS for CC32xx related modules, how could I utilize this tirtos_cc32xx_2_16_01_14?

Any help?

thanks,

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Compiler/MSP430F5514: Can I get the linker to output both a .out file and a .txt file and how do I put constant text arrays into flash rather than ram?

March 29, 2018, 12:41 pm
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Part Number:MSP430F5514

Tool/software: TI C/C++ Compiler

In the specify output file name, can I specify two output files? The current .out file and an additional .txt file to use with the boot loader.

Also, can someone point me to the documentation for the linker?

In addition, what are the compiler/linker commands/key words to a constant array of characters into flash memory rather than ram.

Again, documentation would be useful if I could find it

Thanks,

Gerry Kurz

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IWR1642: Wildlife tracking

March 29, 2018, 12:33 pm
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Part Number:IWR1642

Hello. I am a wildlife researcher and am interested in simultaneously following multiple individuals in the field. Traditional methods use RFID tags, but that is not an option as I require position information. It seems that the mmWave sensor might be able to help. The field is a complicated landscape (trees, branches, moving leaves and other animals), and individuals need to be identified as they move in and out of the sensor range (an individual that moves out of the sensor range must be identified as that same individual when it moves back into sensor range). Because of these issues/requirements, might there be a way to tag individuals that will either bounce back an identification number (similar to RFID tags), OR that will "respond" only to a given frequency (if the mmWave sensor is able to scan in multiple frequencies)?

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