CAPTIVATE-PGMR: Minimum Connectivity to Retain Captivate Design Center Interactivity

Jay09

Part Number: CAPTIVATE-PGMR
Other Parts Discussed in Thread: MSP430FR2512, , CAPTIVATE-FR2633

I have been prototyping using the CAPTIVATE-PGMR and the CAPTIVATE-FR2633 board. In my final design I would like to embed the smaller MSP430FR2512 (I don't need the extra sensor ports).

I plan to program the board using the CAPTIVATE-PGMR, since it has ezFET built in. That said, I was looking at the schematic for the CAPTIVATE-FR2633, and it looks like all I really have to do to achieve that is maintain the connectivity from that development header. My plan was to essentially reproduce this pinout:

In doing so, if my board has its own power, I assume I can drop pins 3,4,5,6. As for the grounds, do I need to keep both of them? Are there any other pins I can remove? I know, for example, the IRQ pin (17/18) is needed for interactivity with the design studio.

Are there other things I should be considering? It looks like the only other thing the board needs is the crystal, for which I will using the following design:

Thanks!

over 3 years ago

0 Eddie LaCost over 3 years ago

TI__Mastermind 38620 points

Hello John,

Have a look at the image of the interface header at the link below. It gives some more description of what each pin is used for. The typical required connections for either I2C or UART are also described in this page.

http://software-dl.ti.com/msp430/msp430_public_sw/mcu/msp430/CapTIvate_Design_Center/latest/exports/docs/users_guide/html/CapTIvate_Technology_Guide_html/markdown/ch_evm_CAPT_PGMR.html

0 Jay09 over 3 years ago in reply to Eddie LaCost

Expert 1030 points

Great thanks for this. So are these connections enough to retain the ability to flash the board from CCS as well? Assuming I will connect with uart in the design center:

Example 6-pin target PCB connections supporting UART communications with CapTIvate Design Center

+3.3v

Ground

SBWTCK_TST

SBWTDIO_RST

UART-TXD

UART-RXD

0 Eddie LaCost over 3 years ago in reply to Jay09

TI__Mastermind 38620 points

Correct. SBWTCK_TST and SBWTDIO_RST are used for programming.

0 Jay09 over 3 years ago in reply to Eddie LaCost

Expert 1030 points

Thanks Eddie! One last thing about this issue:

Here is my completed layout:

In the schematics I referenced, the larger MSPs had dedicated XIN/XOUT pins. I assume it's OK to do things in this way, putting MSP_RDX/MSP_TDX on pins 17 and 16 and XOUT and XIN on 8 and 7.

Ideally I'd like to omit the oscillator, but I am unsure how this will impact the performance of the touch sensing aspects of the MCU.

0 Eddie LaCost over 3 years ago in reply to Jay09

TI__Mastermind 38620 points

John,

Yes, this is okay. You set the functions of the pins using the PxSEL registers. See section 2.8.5 of the users guide for details.

https://www.ti.com/lit/ug/slau445i/slau445i.pdf

Also, your RC on the reset pin is incorrect, but it looks like you have another post where you have corrected it. RST line should go in between the RC.

0 Jay09 over 3 years ago in reply to Eddie LaCost

Expert 1030 points

Hi Eddie,

Great, thank you! Yes, I caught that error during layout but much appreciated you pointing it out.

In the end I decided to omit the external oscillator -- hopefully that's good enough for captivate to function. I put MSP_TXD/RXD on those pins, instead.

Thanks!

0 Eddie LaCost over 3 years ago in reply to Jay09

TI__Mastermind 38620 points

Yes, you can still use the captivate function using the internal LF clock called REFO instead of external oscillator. If this is a test board, you may want to put the pads for a crystal and load caps, but not populate it by default, that way you can add it later if needed or just want to compare performance.

0 Jay09 over 3 years ago in reply to Eddie LaCost

Expert 1030 points

Hi Eddie,

Thank you, that is helpful information. In general, what is the expected difference in performance? I couldn't find any documentation about the impact of using the internal oscillator.

Thanks!

0 Eddie LaCost over 3 years ago in reply to Jay09

TI__Mastermind 38620 points

John,

I don't have any data to show cap touch performance differences. You can find the specification of the calibrated internal LF clock(REFO) in table 7 of the datasheet.

https://www.ti.com/lit/ds/symlink/msp430fr2522.pdf

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CAPTIVATE-PGMR: Minimum Connectivity to Retain Captivate Design Center Interactivity