MSP430FR5992: MSP430FR5992

Fred Assadi

My EE is designing our 5992 MSP to run @ 2.5 VDC. I know that i can disconnect the 3.3 VCC power provided by the TI FET and instead power the SDK (or my custom target) from the local PS.

Assuming a shared ground, is it safe to connect the other 3.3 V FET signals (like RESET, SBWTCK, JTDI...) to my lower voltage MCU?

I see that some of the signals on the FET have a series 330 Ohm resistor, perhaps for this purpose. But just wanted to make sure that I would not damage my FET or my target.

Thanks.

over 4 years ago

0 Evan Lew over 4 years ago

TI__Genius 10060 points

Hi Fred,

You have two options:

Use the MSPFET to power the MCU the board:

The MSPFET has a configuration power supply that can output voltages from 1.8V to 3.3V in steps on 100mV. If you design stays within the current limit of the MSPFET (100mA or 60 if limited by USB) than this option should work for you. Pin 2 of the MSP JTAG connector will supply power. Don't connect pin 4 in this configuration.

Use the target power supply:

The MSPFET will automatically adjust the JTAG signal levels based on target Vcc. Pin 4 of the MSP JTAG connector will power the MSPFET from the Target Vcc. Don't connect pin 2 in this configuration.

Here are a couple related references:

Hardware tools user guide specifically: