MSP430I2041: Code won't run at startup

Hi Erik,

Just so I know a little more about your setup, how do you know when your code is running or not running?  What do you see or not see?

Can you try a simple project that loops and toggles an IO pin?  Trying to rule out anything possibly in your code.

It's a simple modbus code. I do get a response when the MSP-FET is connected and I also get a response on the other board, but not on this board when the MSP-FET is disconnected. Since it runs on the other board I assume there is nothing wrong with the code itself.

Hi Erik,

Do you have a 47k pull up resistor and 1nF capacitor on the RST pin?

The pullup resistor is indeed 47k, but for the capacitor I have 2.2nF as it's value

Hi Erik,

Ok, you're fine with the 2.2nF.

So let me make sure I understand the conditions.  If you just flash the device or run in debug mode, it works.  When you say you 'disconnect' the MSPFET, you mean physically disconnect it from the MSP430, correct?  Do you cycle power after this?

After flashing or in debugmode it works. Even after I cycle power it still works, as long as the MSP-FET is connected. I can even take out the TEST/SBWTCK pin and do a power cycle and it still works. I can disconnect the device from the MSP-FET completely as well and it still works. But when I cycle the power at that moment it stops working. Reconnecting the MSP-FET has no influence. Only reflashing it makes is work again.

Hi Erik,

I have asked around, but nobody seems to come back with any useful suggestions.

Are you using the 2wire (SPY-BY-WIRE) JTAG or the full 4-wire JTAG connections from the MSPFET?

When you are cycling power at the moment it stops working, can you look at the RST and TST pins to see what they are doing before, during and after you cycle power?

Dear Dennis,

I did some probing on the !RST/NMI/SBWDIO pin (since that's the one causing issues) and these were the results.

In this first image the situation with the MSP-FET connected is shown durring a power cycle. The yellow channel is the 3.3 V power line and the blue channel is the !RST/NMI/SBWDIO pin.

This next image is the situation with the MSP-FET disconnected durring a power cycle. As can be seen, the off state voltages are lower when the MSP-FET is disconnected.

Hi Erik,

How do you connect the MSPFET to the PCB for programming?  Can you confirm there is a ground connection for the MSPFET to be tied to the system ground?

Yes, there is a ground connection between the MSP-FET and the MSP430i2041

You indicated the code runs on one package type but not the other.  Which package has this problem?

For the working board a 28-pin PW package was used and for the non-working one a 32-pin RHB package was used.

Hi Erik,

Do you have a capacitor on Vcore?  Do you have more than one board or device that demonstrates this issue? The 32-pin package is a QFN, so is there a possible bad solder joint?

Hi Erik,

One more thing...the 32-pin package has a thermal pad on the bottom that must be grounded.

I have a 470nF capacitor between Vcore and digital ground.

The issue is present at all 3 boards that are made accoriding the same design and the boards are assembled by a PCB manufacturing company and I haven't detected any bad soldering joints myself.

I did connect the thermal pad to digital ground as well

Hi Erik,

I haven't been able to get any new suggestions from our production team.  Have you discovered anything new?