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MSP430FR2633: CapTIvate Electrical Characteristics / Register Map

Sam Vinci
Prodigy 150 points
Part Number: MSP430FR2633


Hello,

I am looking to determine if your MSP430FR2633's CapTIvate peripheral is suitable for a particular design. 

Can you please help me locate the Electrical Characteristics table for the CapTIvate peripheral? 

Can you please help me locate the Register Map for the CapTIvate peripheral? 

I found the MSP430FR4xx and MSP430FR2xx Family User's Guide, but in Chapter 9: CaptIvate Module, it only lists three registers: CAPIE, CAPIFG, and CAPIV. I am looking for the configuration/control register for this peripheral so I can understand its ADC capabilities. 

  • 0
    TI__Mastermind 40040 points
    Hi Sam
    The the Electrical Characteristics table for the CapTIvate periphera is in the msp430fr2633's datasheet which in www.ti.com/.../msp430fr2633.pdf in chapter 4.11.9
    For the the Register Map you can the msp430fr2633's datasheet in chapter 6.13.2.
    There is no ADC in the Captivate peripheral. For more information you read the on line user's guide
    software-dl.ti.com/.../ch_technology.html
    in the Technology chapter.
  • 0 in reply to Gary Gao
    Prodigy 150 points

    Hi Gary,

    There is no chapter 4.11.9 in the msp430fr2633's datasheet. Chapter 4 only goes up to 4.6.

    Additionally, in chapter 6.13.2, it looks like this is the register map you are referring to:

    What I am looking for is a complete register listing for the CapTIvate peripheral. The User Guide only shows these registers: CAPIV, CAPIFG, CAPIE:

    Notice how the EOCIEN bit refers to a bit in a different register called EOCIFG. If you do a search through the PDF for "EOCIFG", the only result is on this page. If you go to the CapTIvate Design Center website and use the search box on the webpage to look for EOCIFG, the search returns no results.

    Please help me find the similar register listing for the CapTIvate registers, as well as a complete Electrical Characteristics table for the peripheral.

    I understand there is no "ADC" in the CapTIvate peripheral per se; capacitance is an analog quantity and it is converted into a digital quantity by the MCU.

  • 0 in reply to Sam Vinci
    TI__Mastermind 40040 points

    I am sorry for the mistake.It should be 5.11.9.
    We just open the three registers: CAPIV, CAPIFG, CAPIE: for customer. Because it is a protected IP so far.
    You can't search the EOCIEN in the online user's guide is because the register description is save as a picture.(Sorry for that. You can find it in "Technology->The Captivate Peripheral->Auxiliary Digital Function") But it is same with the off-line version in pdf.

  • 0 in reply to Gary Gao
    Prodigy 150 points

    Hi Gary,

    This is the small table in section 5.11.9:

    The only parameters listed are 

    VREG, tWAKEUP,COLD, tWAKEUP,WARM, fCAPCLK, and fCAPCLK,DC. 

    I am trying to find parameters such as:

    Size of Reference Cap

    Maximum number of counts

    Linearity (INL/DNL)

    SNR

    THD

    Noise Floor

    Number of Bits

    Effective Number of bits

    Effective capacitance resolution

    Essentially, I am planning to determine the displacement between a capacitance of two parallel plates. If the change in capacitance over the full displacement range is 1pF for example, and I want to determine the capacitance at multiple levels of displacement in this range, I cannot do that if the noise floor is 1.5pF RMS. 

    Can you comment on any of the above parameters?

    P.S. Please don't hide information because TI thinks it is "too hard for the customer". If we are trying to implement something more than copying a cookie-cutter reference design, it is helpful to have as much information as possible about the device.

  • 0 in reply to Sam Vinci
    TI__Mastermind 40040 points

    Hi Sam
    Sorry for the misunderstanding words. The real meaning I want to say is to make the module easy to use for customer.I will change the words,later.
    For the parameters I will try to find them for you:
    Size of Reference Cap , Linearity (INL/DNL) , THD (I will check it with team)
    Maximum number of counts (you can get it in the Captivate design center(CDC), click on the Conversion count you will see the description on right.The range is 100~8191. You can apply this method to other parameters which are showed in CDC)
    SNR you can test it in your real system with CDC.(The CDC have the function)
    Noise Floor (We can control it with the count filter which in the Tuning)
    Effective capacitance resolution (you can refer to on-line user's guide "Design Guide->Best Practices" )

    Best regards
    Gary

  • 0 in reply to Gary Gao
    TI__Mastermind 40040 points
    Hi Sam,

    Some information added
    1.There is no INL, DNL, or ENOB specs for CapTIvate. For the resolution it is depends on how the IP is configured.
    2. what is the overall capacitance range? In other words, is it 1pF of range varying from 1pF to 2pF, or more like 1pF of range varying from 10pF to 11pF?
    3.In the application, would the plates be floating (outside of whatever capacitive sensing excitation signals are applied)?
    4.The CapTIvate is suitable for relative measurements but not absolute capacitance measurements.
  • 0 in reply to Gary Gao
    Prodigy 150 points

    Hi Gary,

    Thanks for the quick reply. Here's a little more information about our application:

    Overall Capacitance Range: Our prototype is calculated to be about 1pF range varying from 22 to 23pF. In Counts, the CapTIvate system reports a change of about 753 counts. 

    For this application, the system consists of two parallel capacitances: a fixed capacitance to GND, and a varying capacitance to GND as the distance between the cap-sense pad and an GND plane is varied. The cap-sense pad is shielded, so I think the answer to your question is no, the plate is not floating.

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