• State Resolved
  • Locked Locked
  • Replies 3 replies
  • Subscribers 79 subscribers
  • Views 678 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

MSP432P401R: RGC(VQFN-64) PCB Circuit requirements

JamesL
Prodigy 90 points
Part Number: MSP432P401R


For my design, I need to use the package quoted in the title, and am looking at the MSP432 hardware design files schematic. I just have a few questions about what blocks are actually required for my design after looking at the datasheets extensively.

Required peripherals:

-5 Digital out pins

-1 ADC input @ 20 kHz+ w/ 12+ bits of accuracy - putting signal through op-amp, so signal level can be changed, and planning on a reference of 2.5 V since it seems that's built in

Questioned block requirements:

1. Do I need the DC-DC block?

2. Do I need the Digital/Analog VCC blocks? If not, do I still have AVCC1/2 connected across a resistor and DVSS1/2/3 and AVSS1/2/3 connected to ground?

3. Do I need the LFX/HFX blocks? I assume not, as 3 MHz processing should be plenty for what I'm doing

4. Is DCOR always connected to the R5 91k resistor into ground?

5. Do I need the RESET block if I don't plan on ever resetting, just power cycling? If not, should I just keep this pin at 3.3 V?

6. Since I plan on using another Launchpad 432 to (no debug) program the PCB 432, the only connections between the 2 I need are:

SWCLKTCK, SWDIOTMS, PJ.5/SWO (SWDIO?), PJ.4/TDI, and RSTN/TMI 

into a 10POS connector, correct (of course with the 3.3V source on 1 and 3,5,7,9 all grounded)?

  • 0
    TI__Guru 65521 points
    (1) The device is a 3.3V device. If you have a 5V supply it will need to be regulated down to 3.3V. The device itself has an internal LDO and DC-DC, which you can choose from to regulate the 3.3V to the core voltage. Please note that the DC-DC converter requires an external inductor.
    (2) You do not need separate analog and digital supplies. This is typically done to help isolate digital noise from the analog.
    (3) If your application can utilize the internal oscillators (DCO, SYSOSC, MODOSC, REFO, VLO) then no external resistors are needed.
    (4) DCOR is used to improve the temperature drift of the DCO. If your design requires a tighter tolerance over temperature, then an external precision resistor with low temp coefficient would be required.
    (5) A pullup on reset is required. Please refer to the Launchpad example, datasheet, and or the Technical Reference Manual for guidance.
    (6) Programming the device can be done through the JTAG as you have shown or the BSL.

    Regards,
    Chris
  • 0 in reply to Chris Sterzik
    Prodigy 90 points

    Just to be clear on (2), DVCC and AVCC just needs to be at 3.3V and DVSS and AVSS at Ground - no capacitor banks or 0 Ohm resistor between them,from what you're saying, right?

    Thanks a bunch for the help, this clears it up a lot.

  • 0 in reply to JamesL
    TI__Guru 65521 points
    Yes, you do not need the 0 ohm resistor between AVCC and DVCC, but it is good practice. As far as capacitors, it is good practice to place decoupling caps as close as possible to the device at each instance of DVCC and AVCC. The other ends of those capacitors should be connected to ground, ideally with as short a trace as possible between the component and the ground plane.

**Attention** This is a public forum