Using TMDSCNCD28069MISO with DRV8301-HC-C2-KIT

Enrico,

If you are trying to use TMDSCNCD28069MISO and the InstaSPIN-FOC GUI with DRV8301-HC-C2-KIT baseboard you need to make sure that the DRV8301 baseboard is REVISION D (as mentioned in the README, QSG, and video).  About half of the kits we sold in 2011-12 were revision C before we moved to revision D.  The GUI project and the MotorWare examples only support revision D.

If you are so inclined you can make the MotorWare projects work with revision C. The only difference is in the pins used for ADC sampling and the scaling in user.h

With revision D we populated the external 3x op-amps (revision C only uses the 2x PGAs on DRV8301) so that we could do 3-shunt measurement and extend duty cycle range beyond what we define as 1.0 up to 2.0 (full trapezoidal).  We also choose to scale the current to 40A to get more resolution to suit more applications (the Rev C default is 80A if I recall correctly).

Hello,

is it possible then to make revision C compatible with Revision D by populating the 2 additional PGAs for 3-shunt current measurement?

Will we be able then to make the software changes you mentioned and enable FOC using InstaSPIN-FOC GUI?

If the conversion is not possible, I suppose that the recommended solution for FOC is DRV8301-69M-KIT which already includes a FOC-capable control card, correct?

Thank you in advance,

Giannis

I don't recommend, it's not worth the effort IMO. It's more than just dropping down the OPA devices.  Spend the extra $200 and get a new Rev D inverter with the 69M kit.

Hi Chris,

thanks for the reply. Are the differences between Rev C and Rev D of the inverter documented somewhere or do we have to crosscheck the schematics ourselves? Can you please explain what more than populating the missing amplifiers and associative passives is required?

Thank you in advance.

Hi Giannis,

I believe these are the only changes, populating the DNP componenets and changing the routing to the DIMM100 header.

I looked over the two schematics and did not see anything else. You can find both of the revisions documented (schematic, layout) in ControlSUITE.

http://www.ti.com/tool/controlsuite

Rec C Schematic

1830.DRV8301-HC-RevC1-RELEASE.pdf

Rec D Schematic

2818.515502~1.PDF

Hi Chris,

thank you for the information.

I see that on REV C.the IA_FB, IB_FB, IC_FB and I-TOTAL are already routed to pins 13 & 59, 9 & 17, 63 & 67, 61 of the DIMM100 respectively ( individual phases signals are connected to two pins each, maybe for interleaved sampling to increase sampling rate?).

On REV D. the above pin assignments are the same but there are also EXT_IA_FB, EXT_IB_FB, and EXT_IC_FB which are connected to pins 69, 19 and 57 respectively. In REV C these pins are unconnected. The EXT_I*_FB (*A,B,C) signals are connected via zero Ohm resistors to the ones with EXT_ in their name, so it seems that all signals are ready available on the DIMM100 connecter on REV C, just not on all the pins that are available on REV D, where each individual phase signal is practically connected to 3 pins.

I have not yet studied the operation f the C2000 processor with the DRV kit to know if the above differences practically limit the possible functions though.

Giannis Roussos said:

I see that on REV C.the IA_FB, IB_FB, IC_FB and I-TOTAL are already routed to pins 13 & 59, 9 & 17, 63 & 67, 61 of the DIMM100 respectively ( individual phases signals are connected to two pins each, maybe for interleaved sampling to increase sampling rate?).

yes, we brought back the signals to multiple pins so we could interleave signals if desired

Giannis Roussos said:

On REV D. the above pin assignments are the same but there are also EXT_IA_FB, EXT_IB_FB, and EXT_IC_FB which are connected to pins 69, 19 and 57 respectively. In REV C these pins are unconnected. The EXT_I*_FB (*A,B,C) signals are connected via zero Ohm resistors to the ones with EXT_ in their name, so it seems that all signals are ready available on the DIMM100 connecter on REV C, just not on all the pins that are available on REV D, where each individual phase signal is practically connected to 3 pins.

If you populate the Rev C you will need to use the EXT_I# pins for the MotorWare / InstaSPIN-FOC solution. The projects are all set-up with pins 69, 19, and 57

from C:\ti\motorware\motorware_1_01_00_13\sw\modules\hal\boards\drv8301kit_revD\f28x\f2806x\src\hal.c

  //configure the SOCs for drv8301kit_revD
  // EXT IA-FB
  ADC_setSocChanNumber(obj->adcHandle,ADC_SocNumber_0,ADC_SocChanNumber_A6);
  ADC_setSocTrigSrc(obj->adcHandle,ADC_SocNumber_0,ADC_SocTrigSrc_EPWM1_ADCSOCA);
  ADC_setSocSampleDelay(obj->adcHandle,ADC_SocNumber_0,ADC_SocSampleDelay_9_cycles);

  // EXT IA-FB
  // Duplicate conversion due to ADC Initial Conversion bug (SPRZ342)
  ADC_setSocChanNumber(obj->adcHandle,ADC_SocNumber_1,ADC_SocChanNumber_A6);
  ADC_setSocTrigSrc(obj->adcHandle,ADC_SocNumber_1,ADC_SocTrigSrc_EPWM1_ADCSOCA);
  ADC_setSocSampleDelay(obj->adcHandle,ADC_SocNumber_1,ADC_SocSampleDelay_9_cycles);

  // EXT IB-FB
  ADC_setSocChanNumber(obj->adcHandle,ADC_SocNumber_2,ADC_SocChanNumber_B6);
  ADC_setSocTrigSrc(obj->adcHandle,ADC_SocNumber_2,ADC_SocTrigSrc_EPWM1_ADCSOCA);
  ADC_setSocSampleDelay(obj->adcHandle,ADC_SocNumber_2,ADC_SocSampleDelay_9_cycles);

  // EXT IC-FB
  ADC_setSocChanNumber(obj->adcHandle,ADC_SocNumber_3,ADC_SocChanNumber_A0);
  ADC_setSocTrigSrc(obj->adcHandle,ADC_SocNumber_3,ADC_SocTrigSrc_EPWM1_ADCSOCA);
  ADC_setSocSampleDelay(obj->adcHandle,ADC_SocNumber_3,ADC_SocSampleDelay_9_cycles);

Thank you Chris!

So it seems that if we modify the MotorWare projects to use the pins already connected in Rev C we only need to populate the missing current sense components.

This is great, it means that we can upgrade our 2 Rev C boards and save 400$.

Thank you for all the help, I will post the results when we perform the upgrade.

Giannis

ok, it's worth a try. I feel like I remember something else though with HW, like the polarity of something is changed....hope it works!

Hi again,

we ended up buying the Rev D kit and now we are developping our own board. I see in the schematic and the MotorWare HAL code that the EXT current feedback signals are used and the ADC conversion sequence is interleaved on the ADC inputs, i.e. the conversion order I1, I2, I3, V1, V2, V3 uses Sample&Hold A,B,A,B,A,B. However, I do not see the ADC being setup for simultaneous sampling, so I would like to know if this arrangement makes any difference in the ADC results or the total measurement time, or can we rearrange the pins for better routing?

Reading the device TRM I see that the total measurement duration is the sampling time (9 cycles in Motorware) and the Conversion time (13 cycles). However it is not clear what happens in simultaneous sampling mode, because if both S&H start sampling at the same time, lets call it cycle 0, the at cycle 9 BOTH have already completed sampling so theoretically only 26 more cycles are needed for a total of 35 cycles instead of 44 for sequential sampling. This would mean that 6 measurement with 9 cycles window each at 45MHz ADC clock would be 2.33us using simultaneous sampling instead of 2.93us in sequential mode. For reference, 1 PWM cycle at 45KHz (relatively fast according to MW) is  22.2us.

If the above assumption is correct, i.e. the measurement time is decreased in simultaneous mode, wouldn't this be useful in MotorWare applications, allowing also the current and voltage of each phase to be sample simultaneously?

Giannis Roussos said:

HAL code that the EXT current feedback signals are used

on the DRV8301 EVM, the DRV8301 chip only has 2 amplifier on-chip.  We wanted to use 3 to be able to show over-modulation (proj_lab10) and we decided it would be better to try to match all three off-chip.  It turns out this really wasn't necessary; on the BOOSTXL-DRV8301 we used the 2 on-chip and 1 external and it works just fine.

Giannis Roussos said:

and the ADC conversion sequence is interleaved on the ADC inputs, i.e. the conversion order I1, I2, I3, V1, V2, V3 uses Sample&Hold A,B,A,B,A,B. However, I do not see the ADC being setup for simultaneous sampling, so I would like to know if this arrangement makes any difference in the ADC results or the total measurement time, or can we rearrange the pins for better routing?

This DRV8301 EVM was designed many years ago, and we layed it out to have the flexibility to do simultaneous sample of current pairs so you can always get two good samples simultaneously....but in MotorWare we never actually set this up.  It is probably "better" but we haven't really seen a big difference.  It would make the most impact at very lowest and very highest duty cycles and especially with lower inductance (higher speed motors).

If you're comfortable doing this you can, but it does add some logic / complexity to your CTRL system on handling the samples.

Giannis Roussos said:

If the above assumption is correct, i.e. the measurement time is decreased in simultaneous mode, wouldn't this be useful in MotorWare applications, allowing also the current and voltage of each phase to be sample simultaneously?

As you noted, the conversion time can be decreased a bit, but that doesn't bring a big benefit. CAPTURING simultaneous signals is more beneficial, but even that is a pretty small benefit most of the time.