Why are there 3 ADC0 event Mux trigger sources possible for 3 PWM modules but the PWM generator triggers are tied together?

Hi Amit,

Lets agree then the individual triggers are not all tied together into one PWM module signal being Fig23-1 does say (triggers).

Then should not the ADCEMUX in any single sequencer (EM0-EM4) be capable to MUX any single or multiple PWM generator output triggers into one dedicated sequencer trigger? That action OR's 3 triggers into one output as a mux would do in any single sequencer FIFO capable to select any logical combination of the named sources in any single or multiple EMx bit sets. 

If we program 3 PWM generator trigger sources separately ADCSequencerConfigure() only the last trigger source (PWM2) is actually being programmed and triggers samples as expected. That confirms PWM GEN0 is not the only trigger (PWM0INTEN) source possible in any single or perhaps multiple bits EM0-EM4. Yet when we HWREG mux 3 PWM generators (shown above) into EM0 or EM1 the ADC stops sampling for the LM3, not so sure about the TM4C.

Was combining 3 PWM generator triggers into a single FIFO not supported on LM3 and now is on TM4C, if not why not?

BTW:

Tivaware is doing the same thing Stellarisware was doing by configuring only the last ADCEMUX entry. Even OR'ing the 3  trigger sources in one statement in Stellarisware set the EM0/EM1 to 0xf trigger always. The reason to use HWREG forcing an ( |= ) in the same EMx FIFO bits.

Hi Amit,

>The FIFO has been designed for multiple design scenario and not just motor control

Motion control is boasted feature of the TM4C yet the architecture of the PWM/ADC peripherals is bottle necked at the ADCEMUX. Suppose we want to generate 3 phase DC to AC inverters using 3 PWM generators, each 120 degree phase angle. Again 3 sequencers of the 4 total in either ADC peripheral must be sacrificed since the ADCEMUX is bottle necking the sequencer. Seemingly that is what steps are for so the sample window can follow the source with as little interruption as possible in near real time. Reprogramming the same sequencer repeatedly for a different generator trigger source is time consuming and seemingly invites mayhem. Yet that may be the most effective way to use the same sequencer with 3 PWM generators in the present TM4C architecture.

Have read your idea a few times but seem to get lost in how the ADCEMUX can be set to trigger from 3 PWM generators using only one sequencer. The scenario infers all the other sequencers are occupied, only one sequencer exists for 3 generators load count triggers.

Another solution may be to reprogram the ADCEMUX for the same sequencer each time the PWM generator changes. A zero count interrupt handler for each generator can reprogram the ADCEMUX so the load count trigger is ready at top center of load count. That would give some settling time in the ADCEMUX before reaching the top of count. That as well may be plagued by current phase angle issues if the PWM output control block is driven by an source such as Halls or sequence reload timers. Another idea uses an edge count timer that follows each PWM generator B output pin triggering an interrupt handler routine reprogramming the ADCEMUX in sync with the actual (gated) generator pin event versus the free running PWM load count events. Relying on PWM (load count) triggers solely for ADC samples seems to me where the problem of following exact current phase angle is being introduced.

Hi Amit,

So it seems only the interrupt source is set by configuring the interrupt pin type and the service handler IM entering it in startup_ccs.c? Never really connected the dots before yet knew we had to add the handler for the interrupt to vector.

That said do we still have to clear the GPIO interrupt source each interrupt cycle, my thought is in the ADC interrupt handler?

Thanks :)

Hi Amit,

It seems plausible each of the OR'd GPIO pin interrupt trigger sources should be cleared in samples interrupt handler.

MAP_GPIOPadConfigSet(GPIO_PORTQ0_AHB_BASE, GPIO_PIN_2, GPIO_STRENGTH_2MA, GPIO_PIN_TYPE_STD);
MAP_GPIODirModeSet(GPIO_PORTQ0_AHB_BASE, GPIO_PIN_2, GPIO_DIR_MODE_IN);

/* ADC trigger source edge event interrupt initiator */
ROM_GPIOIntEnable(GPIO_PORTQ0_AHB_BASE, GPIO_INT_PIN_2);
ROM_GPIOIntTypeSet(GPIO_PORTQ0_AHB_BASE, GPIO_PIN_2, GPIO_RISING_EDGE | GPIO_DISCRETE_INT);
ROM_GPIOADCTriggerEnable(GPIO_PORTQ0_AHB_BASE, GPIO_PIN_2);
ROM_IntEnable(INT_GPIOQ2);

Hi Amit,

It seems to me if the interrupt is not enabled or simply removed the GPIO rising edge event would not trigger the ADC. The real question then, is the ADC external trigger source considered an NVIC or GPIO source event?

Hi Amit,

Would like to test this same configuration on legacy LM3 being the INA282 shunt current monitor is so dang precise. After the low level ADC sample noise was removed by replacing Opamps doing current monitoring it was revealed PWM GEN0 triggered load count samples are not covering all the electrical angles. The problem seems that trapezoidal wave shape is complex, has good and bad attributes, some we want to monitor current and others we might want to ignore. 

That sample behavior now restricted by comparator monitor at times catches random undesired current spikes tripping the PWM fault comparator. Seems an indication the pitfalls of single generator trigged ADC samples in a 3 phase 120 degree phase angle topology. Would like to prove that hypothesis on legacy LM3 before adopting to TM4C current monitor schema. The problem with LM3 uses GPIO pin B4 the only selection available in the ADCEMUX for all 4 sequencers.

Another possibility perhaps TI engineers can check hypothesis 3 generator ADC triggers TM4C123 with BOOSTXL DRV8301 in the lab. The DRV8301 is shown mated to C2000 Piccolo F28027F yet is close to EK-TM4C1294XL booster pack 2 header pin layout but for only a few pins. DRV8301 might mate with the EK-TM4C123XL launch pad but couldn't say for sure. The point is wouldn't TI engineers also like to know for sure as I did?

Hi Amit,

See how nice the current looks after SW changes sample data is filtered in sync to PWM triggers. Seems am on to something when the samples start to visually relay real time oscilloscope attributes. Imagine how digital current might appear if all 3 generators could trigger samples driving low side MOS and capturing/displaying each phases current events in real time.

Results of 3 separate ADC samples of current triggered from PWM0 Gen0 shown below. Ideally the PWM single ADC triggers 3, one each generator yet can't. Unless later discussed posts below ADC samples are triggered remotely via GPIO monitor inputs on each PWM generator.

Target current set below maximum peak so the duty cycle pulses are filtered:

BP101 said:

Seems I am on to something here

Would not that, "On to something here" be far better supported with the display of the more normal/expected, "Wider PWM" drive signals?      

Are not those - rather narrow (power-limiting) - PWM pulse widths eroding the claim?   (i.e. setting the goal-posts (lower AND closer) may not be overly convincing!)

Let's say, "All of that is true" (I'm unconvinced) would it not be far more impressive (and marketable) if you'd post such, "high definition view of each FET inductive avalanche" (huh?) at reasonable power levels - not "dialed down" to (almost) 500W (i.e. toy) level?   Does a motor - bolted down to your basement concrete - require such "securing" if we're driving ONLY @ LESS THAN ONE-TENTH of its capacity?   (i.e. you "claim" an Avalanche - yet curves reveal (at most) small Snowflake!)
 
You know that firm/I are, "tech promoters" - those (rather pedestrian) curves/values generate little (i.e. no) excitement - can't you post a more meaningful (i.e. similar size/shape curves but @ 2KW (or greater) output?)

That's marketable - that presented (thus far) not at all...

The point of INA282 in RDK was to gain a more accurate before and after DOE analysis. How do we prove the 20th century has a few things wrong about horse power now being defined and directly tied to Kilowatts. This latest DOE analysis proves that is not true at all especially of BLDC motors as they get more efficient at higher voltage. The US Department of Energy has lately pushed claims that HP coverts directly to KW in all motors and or engines.

BP101 said:

The US Department of Energy has lately pushed claims that HP coverts directly to KW in all motors and or engines.

That equivalence is true by definition. Both are measures of the physical property of power.

This is quite different from brake horse power which is often used to rate engines.

Robert

BP101 said:

Unfortunately internet conversion calculators and various formula make no such distinction in classes of horse power in that definition.

That would be because there is no relation between brake horse power and kW. Brake horse power is largely a measure of motor inertia.

BP101 said:

The DOE attempt to rate all motor as if the KW produced always has a direct relation to HP is 20th century bunk based on AC and not DC power creating simulated AC current.

HP and KW remain distinctly different animals - not so easily to mix one with the other and expect any formula will produce the same outcome in all cases.

Wrong.

BP101 said:

Will the true horse power please stand up: If a generator typically requires 18 HP diesel engine to produce 12KW of 220VAC how can we say it takes the same electrical +/- HP based on the AC KW alone.

I expect you will find both the engine and the generator get rather warm.

Robert

The unspoken word (Torque) is missing in that improper conversion from KW to HP.

KW don't convert in any way directly into Torque which is relative only to (Torque pounds * RPM / 5252 = HP). One might surmise heat energy (KW) released by producing Torque is partly equivalent to a small part of KW but not in an exact calculable amount. Only when we know one side of the equation can we truly know the other is even valid otherwise the formula is useless to predict required HP for the required KW output.

Kilowatts are reactive energy resulting from producing torque in the presence counter EMF. Professors need to clarify the difference between LEZS law and counter EMF as reactive energy which they have yet to do.

The plotted GUI examples above and many other independent scientist are proving that formula is not always correct in predicting the Required KW in the aspect of required Torque. How do we know it requires 18HP diesel to run a 12KW AC generator and otherwise a 24HP gasoline engine is relative mostly to Torque not so much KW.

Seemingly predicting the torque relation to the required KW energy output becomes a better method in determining the wasted reactive heat Energy. The problem then becomes which way to go with current in order to achieve less destructive wasted KW and more efficient Torque. It seems in BLDC motors pushing current down and voltage up produces less destructive reactive KW energy and more efficient torque results. Thanks to the INA282 current shunt monitor for bringing out that aspect of current versus voltage. Form the basics, voltage is the electrical pressure behind current then seems to have a missing entry in the equation for an unknown amount of counter EMF reactive energy. Perhaps a Yokogawa power analyzer would shed some light in the absence of any real or proven science supporting the GUI plots above.

Jim gives a good presentation on reactive energy which it seems he is describing torque. I for one appreciate what Jim has done to reveal the hidden inner truth of reactive energy.

https://www.youtube.com/watch?v=HK3JOlY0V8Y&feature=player_embedded

BP101 said:

The unspoken word (Torque) is missing in that improper conversion from KW to HP.

Wrong

BP101 said:

KW don't convert in any way directly into Torque

It does in exactly the same fashion as HP.

This is basic (first year undergrad, and probably high school) physics.

Robert

That's a nice calculator, a bit more convincing but then again creates even more questions about the INA282 and LM3S8971 MCU test results. The calculator is not exactly correct in matching the KW to HP on my 12KW generator. In reality it requires a lot more HP to get 12KW from the generator than the calculator proves. For some unknown reason the V36 BLDC motor defies all present day formulas and calculators!

The results above GUI plots of motor (TI INA282 current detection) has the same load conditions in each case. Seems to me in science we shouldn't accept the first test result as being remotely correct and simply disqualify the second because it defies power calculators or formulas.  

That is not saying Robert you are wrong as several times you have done based on what you believe to be true in your mind. You argue in the scope of these test results around present day formulas yet the test results say they may be wrong. Perhaps these results have something to do with (F=MA) moving magnetic flux domains have velocity within a larger moving mass at specific flux (voltage) cancels out some of the effects of counter counter EMF in the phase coils. Far as I know the V36 BLDC motor is the first ever built by mankind (us) so there has never existed any such prior testing. BTW the Obama DOE turned down our unsolicited grant proposal to further the research on the V36 BLDC motor stating like technology already exists. Well then shouldn't electric cars now be getting 1000 miles distance between charging the battery?

Keep in mind Einstein rewrote all text books in the 20th century when the entire science community defied his find that gravity bends photons around planets. It's no wonder man kind is still struggling with the Effects of counter EMF, HP and KW in the 21st century. These test results warrant a higher investigation level than we are capable to provide mankind with from my basement.

BP101 said:

In reality it requires a lot more HP to get 12KW from the generator than the calculator proves.

You're surprised by this? Seriously!!?

BP101 said:

DOE turned down our unsolicited grant proposal to further the research on the V36 BLDC motor stating like technology already exists. Well then shouldn't electric cars now be getting 1000 miles distance between charging the battery?

The range limitations of electric vehicles (cars or otherwise) are not due to either motor or controller and have not been for at least 25 years. Anyone who thinks otherwise is doomed to disappointment.

Robert

So it seems you agree we can't convert exactly a known output KW to the required HP to develop a given known KW rating. Adding the torque in the formula helps in that conversion calculator and makes for a good effort truer final answer. Had searched back awhile ago for similar calculator got stuck with the basic.

Have to agree with battery range in part due to lack of serious battery voltages.

>The range limitations of electric vehicles (cars or otherwise) are not due to either motor or controller and have not been for at least 25 years. Anyone who thinks otherwise is doomed to disappointment.

Sorry to disagree - basic results are posted here for anyone with an open mind will see higher voltage has a direct effect in this custom BLDC motors efficiency. Combined to a rudimentary BEMF rotor position, hesitate to imagine what Piccolo C2000 FOC might do with it. Seems a bit of an opinion in claim progress should simply stop on BLDC designs which in the last 25 years until recently have not improved by much in efficiency or run at higher voltages for extended time. Otherwise the claim of range would much further along than 300Km.

FEM analysis has become more accurate and NdFeB has helped efficiency. There is lots of room for improvement non of which many companies were awarded in kind grants that others of lessor impact received under the Obama run DOE. Most of those grantors are now bankrupt gives us a clue to what really went down. BTW the battery voltages mysteriously keep inching there way up from 97v-137v-173v perhaps they to see a similar pattern. Our BLDC motor could be easily made to run at 1200vdc in that scenario where expent heat in similar motors becomes is an issue with NdFeB magnets, not so much with Sm2Co17 which tolerate up to 350 Celsius prior to demagnetization. The point is to recover the reactive energy before it becomes expent as wasted heat not simply throw it away.