Connecting the MSP430FR5722 to the FET debugger.

Christopher Hack

Other Parts Discussed in Thread: MSP430FR5722

Hello,

I am a student attempting to get an MSP430FR5722 attached to a custom PCB to connect to the MSP FET-Emulator tool. I have had no luck getting it to connect after multiple attempts. I have verified that the header I'm using to connect to the PCB is connected to the correct pins on the debug tool, that there are no shorts between the pins, and that there is continuity between the PCB header pins and the corresponding pads on the MSP430. We are using the IRGER package, so it is a little difficult for us to do resolder work.

Is there anything special I need to do in Code Composer Studio in order to get the FET to recognize the MSP? Are there any tests we can do to determine if the MSP's internal circuitry has been damaged? If the maximum reflow temperature is listed at 260c and it was heated to 265c, is it possible that something was broken internally? I'm at a loss as to why this isn't working.

I have attached my schematic for the connections to the MSP for reference.MSPcontrol.pdf

Thank you in advance for your help.

-Chris Hack

over 9 years ago

0 Dennis Eichmann over 9 years ago

Guru 74080 points

First thing I see in your schematic: There is a 2.2uF capacitor at RST which is quite large and will probably prevent the FET from toggling the RST-line.
Is the FET recognized in the device manager?

0 Leo Bosch over 9 years ago in reply to Dennis Eichmann

Guru 23000 points

Additionally to Dennis; The 2.2uF will prevent the FET to work at all. I think you made a little mistake here, it should be max 2.2nF!

0 eltury over 9 years ago in reply to Leo Bosch

Genius 3330 points

For Spy by Wire - is no capacitor a problem? Should there be at least some C for noise?

0 Dennis Eichmann over 9 years ago in reply to eltury

Guru 74080 points

You can program it without the capacitor. But for normal use without a FET connected the capacitor delays the MCU startup to let the supply voltage become stable. So the recommended RC combination was set to 47k + 2n2 to ensure operation with the FET connected. But 2u2 is much too large. In general you can put any value you want on RST - put 100uF in there - no problem at all. But not for programming. If the capacitive load is too large, the FET can't handle it.

0 eltury over 9 years ago in reply to Dennis Eichmann

Genius 3330 points

Thanks Dennis, but my question still is should there be some C while programming?

0 Dennis Eichmann over 9 years ago in reply to eltury

Guru 74080 points

Why not using TI's recommended component values?

processors.wiki.ti.com/.../JTAG_%28MSP430%29

0 eltury over 9 years ago in reply to Dennis Eichmann

Genius 3330 points

I am. This is a philosophical question.

0 Dennis Eichmann over 9 years ago in reply to eltury

Guru 74080 points

For programming it is more of a hindrance.

0 eltury over 9 years ago in reply to Dennis Eichmann

Genius 3330 points

Thanks Dennis. That is the answer I was looking for.

0 Jens-Michael Gross over 9 years ago in reply to eltury

Guru 227245 points

With a bit of math, a higher cap can be used wihtout hindering programming (especially SBW): Since the cap is meant to slow down RST in relation to a rising VCC, it doesn't matter if it takes longer to charge, as long as the resulting RST level is below the low threshold while VCC is still rising.
So a series resistor to the cap will reduce its influence on the high-speed programming signals. It will also reduce the delay effect on RST while power-up, but too a much smaller extent. I once did a calculation (and posted it in one of my many threads) but since I don't use SBW, I didn't keep it.

**Attention** This is a public forum

MSP low-power microcontrollers

MSP low-power microcontroller forum

Connecting the MSP430FR5722 to the FET debugger.