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PGA900EVM: PGA970EVM

Part Number: PGA900EVM
Other Parts Discussed in Thread: PGA970EVM, USB2ANY, PGA970

Hi,

I am using PGA970EVM with usb2any. I have issue of sine wave frequency. I set 5KHz  in WFM Frequency. Then I populate waveform table and click on write. Then clicked on Generate then I am getting 1.812KHz frequency. 

I checked at PI(TP16). There also 1.812KHz. What is going wrong.

Thanks.

Somnath

  • Hello Somnath,

    Do you have a load attached to the output? And what are you using?

    Can you show your waveform output settings? And can you dump the waveform table contents and share them?


    Regards,

  • Hello Scott,

    Currently nothing is given to the output. But this problem arise only after I connected HB LVDT probe(T101F peterhirt make). But after disconnecting load then also this problem remained same.

    I have attached wavefrom coming on DSO, waveform table and waveform output settings.

    Waiting for your reply.

    Thanks and regards,

    Somnath

    PGA970 Waveform Data.txt
    Address(Hex)	MSB(Hex)	LSB(Hex)
    0	00	4D
    2	00	E8
    4	01	82
    6	02	1B
    8	02	B5
    A	03	4D
    C	03	E5
    E	04	7B
    10	05	11
    12	05	A5
    14	06	38
    16	06	C9
    18	07	59
    1A	07	E7
    1C	08	72
    1E	08	FC
    20	09	83
    22	0A	08
    24	0A	8B
    26	0B	0A
    28	0B	87
    2A	0C	01
    2C	0C	78
    2E	0C	EC
    30	0D	5D
    32	0D	CA
    34	0E	33
    36	0E	9A
    38	0E	FC
    3A	0F	5B
    3C	0F	B5
    3E	10	0C
    40	10	5F
    42	10	AD
    44	10	F8
    46	11	3E
    48	11	80
    4A	11	BD
    4C	11	F6
    4E	12	2A
    50	12	5A
    52	12	85
    54	12	AB
    56	12	CD
    58	12	EA
    5A	13	02
    5C	13	16
    5E	13	24
    60	13	2E
    62	13	33
    

  • Hello Scott,

     Any updates on frequency issue?

    Thanks and regards,

    Swapnil

  • Hello Scott,

    I checked in all forum and found many peoples have same issue. They found only solution is to change IC PGA970. 

    Waiting for your reply.

    Thanks and regards,

    Somnath

  • Hi Somnath,

    It does appear that everything is set up correctly. There have been similar reports like you mentioned that may be due to a defective PGA970 device. Where did you purchase the EVM? If you return the EVM through the store that you purchased it then you should be able to get a replacement. What is the top-marking on the PGA970 device that is soldered to your EVM?


    Regards,

  • Dear Scott,

    PGA970 was working perfectly. Problem arised only when I tried to connect 3 wire HBT to it.

    Anyway, TOP marking is,

    PGA970Q

    83T,

    CH4E

    How to program PGA970 through USB2ANY? 

    Thanks and regards,

    Somnath

  • Hello Somnath,

    Thank you for the information. Can you also show a simple schematic with the connections that you made between your LVDT and the PGA970?

    Regards,

  • Hello Scott,

    I had done connections as per attached schematic. Please let me know if I am doing something wrong.

    Thanks and regards,

    Somnath

    PGA970_CON.pdf

  • Hello Scott,

    If I purchase new PGA970 IC then will it come with firmware loaded or blank?

    If it is blank then can I program it with USBANY? Please guide me how to program it? Or will it program with XDS200 only?

    I compiled program in CCS and hex file is generated. I tried to program it through PGA970 UI in FRAM Programming. But after Verify FRAM, NOT matched status is not changing. Why? 

    Also in SOFTWARE INSTALLATION USER GUIDE, OTP memory is mentioned. What it means?

    Please reply as soon as possible. Project is urgent.

    Thanks and regards,

    Somnath

  • Hello Somnath,

    Any new PGA970 IC that you purchase will come with all of the EEPROM, RAM, and FRAM empty. You can program through the USB2ANY using any of the available digital interfaces. For example there is a section in the datasheet called "FRAM Programming Using SPI" which gives a detailed procedure on how to program the FRAM. There is a similar section which describes how to program through OWI.

    Is the firmware that you have developed based on the PGA970 example firmware? You may need to change the PGA970.cmd file to ensure that it is instructing the firmware to be loaded in the correct memory space for the FRAM and  not to load into the DEVRAM.

    Please ignore the mentions of OTP, since there is no OTP memory in the PGA970. It is referring to the FRAM program memory space.

    I am looking into the waveform generation issue and I will get back to you as soon as I can.

    Regards,

  • Hello Scott,

    Any news related to waveform generation issue. 

    I replaced new PGA970 IC in EVM board then it start working fine. Waveform coming as per setting.

    I interfaced HBT probe to PGA1(S1P and S1N) using external inverting and noninverting amplifier with unity gain. It worked fine(I observed it for 2 days). Then same I connected another HBT probe at PGA2(S2P and S2N). Again Waveform generation problem start. Before connecting to pga2, I checked all signals like primary excitation and differential output from external opamp. All signals were fine. Now it is giving 3.9KHz for setting of 5KHz. What may be issue?

    How much the maximum voltage is okay at S1P and S2P? Because my inverting and non inverting signals were 2V pk-pk but riding on 7.5V dc.

    Any other precaution should I take?

    Please accept friend request.

    Thanks and regards,

    Somnath

  • Hello Scott,

    Please update.

    I have lot of orders ahead. Project is urgent.

    Waiting for your feedback.

    Thanks and regards,

    Somnath

  • Hi Somnath,

    Just to clarify, after connecting the waveform output to the S2N and S2P the waveform generation stopped supplying the correct frequency, and it never returned to the correct frequency, even if the second HBT probe was removed?

    You are most likely running into an issue with the voltage levels at the S1 and S2 gain inputs. The input voltage maximum at each pin is specified at 2V (6.12 Electrical Characteristics – S1 and S2 Gain).

    Regards,

  • Hi Scott,

    Just to clarify, after connecting the waveform output to the S2N and S2P the waveform generation stopped supplying the correct frequency, and it never returned to the correct frequency, even if the second HBT probe was removed?

    Yes. It never comes to correct frequency even if I removed all probe connections.

    You are most likely running into an issue with the voltage levels at the S1 and S2 gain inputs. The input voltage maximum at each pin is specified at 2V (6.12 Electrical Characteristics – S1 and S2 Gain).

    Okay. I will take care of it.

    On earlier you told new chip come with empty. But when I replaced old chip with new one then without loading hex file into Fram it start working. Is there no need to download hex file into PGA970 using XDS200?

    Thanks and Regards,

    Somnath

  • Hi Somnath,

    There are a couple of FRAM registered that are pre-written to the device. These are for things like the DAC_VCM value and some calibration points for the internal temperature sensor. The waveform data may also be pre-written with an example, but there should not be any program code in the FRAM to start with.

    Regards,