AM2432: TIDEP Example DMC_LEVEL_1 SDFM scale

Alexander Hänel-Baas

Prodigy 170 points

Part Number: AM2432
Other Parts Discussed in Thread: SYSCONFIG, TIDEP-01032

in the TIDEP example BUIDL_LEVEL_1 I would like to check the SDFM scale as described.

Here it says that the offset should be about half of the OSR configuration.

In the example, the OSR is set to 262144.0. In the screencout, however, you can see the value: 2052

How is this to be understood?

I want to understand this, because for me only the 1st value is about half of the configured value. The other two values show something different.

What could be wrong?

BR Alexander

3 months ago

0 Jomy Paul P S 3 months ago

TI__Intellectual 2080 points

Hi Alexander Hänel-Ba,

I will look into this issue and get back to you shortly

Thanks,

JOMY

0 Achala Ram 3 months ago in reply to Jomy Paul P S

TI__Expert 4870 points

Hi Alexander,

What SDFM OSR value and SINC filter type are you configuring in SysConfig? As mentioned in the comment, 262144.0 is the value for an OSR of 64 and a SINC3 filter.

The expected maximum SDFM output value can be calculated as (OSR)^(SINC_Filter_Type).

BR,

Achala Ram

0 Alexander Hänel-Baas 3 months ago in reply to Achala Ram

Prodigy 170 points

Hi Achala,

You're right. OCR=64 and SINC3 is configured in the sysconfig.

This is the same value for all channels (0-5).

I wonder why the calculated value is only for the 1. Elemet (offset_I_ad [0]) looks correct, but a different value was calculated for Elemet [1-2].

What I would like to understand further is:

- I now configure this value via SysConfig or via the define in hal.h?

- Why is there a completely different value (2025) in your example, when I have loaded the example unchanged?

BR Alexander

0 Achala Ram 3 months ago in reply to Alexander Hänel-Baas

TI__Expert 4870 points

Hi Alexander,

Alexander Hänel-Baas said:
I now configure this value via SysConfig or via the define in hal.h?

- Why is there a completely different value (2025) in your example, when I have loaded the example unchanged?

The expected value is half of the max SDFM output, as mentioned. The attached image may have been captured for a different OSR, it looks like it is for OSR 16 with SINC3 filter. The OSR and SINC filter type are configured in SysConfig, and this offset value depends on the OSR and SINC3 filter type configured. If you want to use a different OSR or SINC filter type, you need to update both places sysconfig as well as hal.h https://software-dl.ti.com/processor-industrial-sw/esd/motor_control_sdk/am243x/2025_00_00_06/docs/api_guide_am243x/EXAMPLE_TIDEP_01032_REFERENCE_DESIGN.html#autotoc_md338

Alexander Hänel-Baas said:
I wonder why the calculated value is only for the 1. Elemet (offset_I_ad [0]) looks correct, but a different value was calculated for Elemet [1-2].

Is this the case for all other channel1-5 ? Can you ensure the other channels are getting the correct inputs and that the configured OSR is the same as for channel 0?

BR,

Achala Ram

0 Alexander Hänel-Baas 3 months ago in reply to Achala Ram

Prodigy 170 points

Hi Achala,

Yes, I am sure that all channels have the same value,

But channels 1-2 are not receiving the same input...

I forgot to insert jumper 27 for 3-wire SDFM.

Thank you very much for the tip about the keyword: Input

Now I am getting the correct values.

Alexander

0 Alexander Hänel-Baas 3 months ago in reply to Alexander Hänel-Baas

Prodigy 170 points

Hi Achala,

I am still wondering why I now have to install the jumper J27 to get valid SigmaDelta currents for all 3 phases,

when your documentation says that this jumper is NOT to be installed?

Please look on page 11.

BP-AM2BLDCSERVO AM2x BLDC Servo Motor BoosterPack (BP-AM2BLDCSERVO)

Can you tell me what I am misunderstanding here.

Alexander

0 Achala Ram 3 months ago in reply to Alexander Hänel-Baas

TI__Expert 4870 points

Hi Alexander,

For SDFM AM243x LP pins we do not require this routing for the current sensing path, so we have marked them as off in the TIDEP-01032 AM243x project doc. Installing these jumpers routes current sense and voltage sense to the jumper pins, as described in the BP user guide.

As mentioned here, these pins are mapped to ADC pins, not PRU SDFM pins, so we do not need this.

BR,

Achala Ram

0 Alexander Hänel-Baas 3 months ago in reply to Achala Ram

Prodigy 170 points

HI Achala,

I'm talking about the Jumper J27!

BR Alexander

+1 Achala Ram 3 months ago in reply to Alexander Hänel-Baas

TI__Expert 4870 points

Hi Alexander,

This is a correction in the doc.

For the AM263PX encoder path, it should be disconnected, and for the SDFM AM243X path, it should be connected.

The image below shows how the J28/J27 different signals are routed: when the jumper is not connected, it follows the red line; when the jumper is installed, it follows the green line.

Achala Ram

0 Alexander Hänel-Baas 3 months ago in reply to Achala Ram

Prodigy 170 points

Hi Achala,

>>For the AM263PX encoder path, it should be disconnected, and for the SDFM AM243X path, it should be connected.

Please correct the doc!

BR Alexander

Processors

Processors forum

AM2432: TIDEP Example DMC_LEVEL_1 SDFM scale