CCS/MSP-EXP430FR6989: Turning Off EnergyTrace Switching supply and using the LDO instead.

Hi Tindel,
You can use an external power supply instead of getting it from the EnergyTrace switching regulator.

Best regards,
Cash Hao

Hi Tindel,
I think you can make some fly wires from the linear regulator to the 3V3 pin. And cut off the wires that connected to the switching regulator.

Best regards,
Cash Hao

Cash Hao said:

I think you can make some fly wires from the linear regulator to the 3V3 pin.

As Tindel has already mentioned, the schematic for the MSP-EXP430FR6989 shows the EZFET_VCCTARGET supply voltage can be switched between EZFET_VCC (the 3.3V LDO output) or EZFET_VCCOUT (the output from the software controlled DC-DC converter):

Where the EZFET_VCCEN1 and EZFET_VCCEN2 controls are connected to the MSP430F5528 which runs the EZFET firmware:

From looking at the MSP Debug Stack source code in slac460 I think the EZFET will select the LDO as the EZFET_VCCTARGET supply voltage when Energy Trace is disabled, but don't have the test equipment to measure this.

Can you confirm if the MSP Debug Stack provides a mechanism to switch EZFET_VCCTARGET supply voltage between EZFET_VCC (the 3.3V LDO output) or EZFET_VCCOUT (the output from the software controlled DC-DC converter)?

Chester,

Yes this is what I was getting at - thanks for helping me clarify.  I too downloaded the debug stack at one point, but I couldn't discern where the debug stack actually enabled the LDO.  I also thought about modifying the stack to turn on the LDO by default but I was unsure of how to load the software, or how if it would interface properly with the CCS after it was loaded.

Sounds like you figured out that the LDO will be used when the energy trace is disabled.  Do you know how to disable it?  I could probably confirm if it was turned off or not with a simple test of my sensor.  I looked through out CCS and couldn't find a way to disable EnergyTrace.  I haven't found anything in any of the energyTrace configuration settings within CCS that I thought would disable energyTrace.  I played around with the settings also, but couldn't find an answer quickly so I moved along.

It does look like this document: http://www.ti.com/lit/an/slaa603/slaa603.pdf shows an "Enable" checkbox on pg 5.  This checkbox is not present in new versions of CCS.  Perhaps if I went back to version 6.0 (which this document references) then that checkbox would still be active.

Tindel said:

Sounds like you figured out that the LDO will be used when the energy trace is disabled.  Do you know how to disable it? 

When the "Enable Auto-Launch on target connect" option on the CCS 8 preferences is NOT ticked:

When starting a debug session for a MSP-EXP430FR6989 used the CCS Debug Server Logging to confirm that the MSP430_DisableEnergyTrace function in the MSP430 Debug Stack is called.

From looking at the MSP430 Debug Stack source code think that MSP430_DisableEnergyTrace will result in the the following in DLL430_v3\src\TI\DLL430\EnergyTrace_TSPA\EnergyTraceManager.cpp being called to select the LDO:

void EnergyTraceManager::stopPolling()
{
	mPollingManager->stopEnergyTracePolling();

	if (mParent->getControl()->getFetToolId() == eZ_FET_WITH_DCDC_V2x)
	{
		//switch on dcdc supply
		HalExecElement* el = new HalExecElement(ID_Zero, coreSwitchFet);
		el->appendInputData16(mParent->getConfigManager()->LDO_ON);
		HalExecCommand dcdcCmd;
		dcdcCmd.elements.emplace_back(el);
		dcdcCmd.setTimeout(15000);
		mParent->getControl()->send(dcdcCmd);

		if (WarningFactory::instance())
		{
			WarningFactory::instance()->message(MESSAGE_LEVEL_T::MSPDS_MESSAGE_LEVEL_INFORMATION, WarningCode::WARNING_LDO_SUPPLY);
		}
	}
}

I was hoping to build the MSP430 Debug Stack for debug from the source code in slac460y, and attach Visual Studio to CCS to confirm that the MSP430 Debug Stack does tell the Ez-FET firmware but had trouble installing the correct tools to build the MSP430 Debug Stack, so haven't yet been able to confirm my theory.

See Linux: Compiling MSP Debug Stack in linux for one work-around for an error building the MSP430 Debug Stack.

When the "Enable Auto-Launch on target connect" option on the CCS 8 preferences is NOT ticked:

I disabled that checkbox and tried it in debug mode. I can confirm that disabling that check box does NOT turn off the switching supply. There is about 30mV of switching noise on the 3.3V rail and L101 switching node continues to switch.

Tindel,

in the post e2e.ti.com/.../691229
I have written:

TI says:
In debuggers that support EnergyTrace™ technology, a software-controlled DC-DC converter generates the target power supply.
And a few paragraphs down:
EnergyTrace™ technology is included in Code Composer Studio (CCS) version 6.0 and later, as well as the latest version of IAR Embedded Workbench.

Feature, you are asking for, is not supported under CCS v6.0 and higher.