TMS320F28379D: rotary transformer

Rhea Gao

Part Number: TMS320F28379D

Hi，

I have a customer who uses F28379D and would like to know whether SDFM module can be used for rotary decoding? The customer wants to know whether it is possible to use SDFM to complete the decoding output without external AMC1305? What are the advantages of this over ADI's AD2S1205?

Many thanks~

over 1 year ago

0 Kevin Allen18 over 1 year ago

TI__Mastermind 40825 points

Hi Rhea,

Have you looked at the eQEP module of F2837x device? It's specifically designed for interfacing with linear or rotary incremental encoders.

SDFM module is meant for interfacing with sigma-delta modulators (i.e. ADCs).

Best,

Kevin

0 Rhea Gao over 1 year ago in reply to Kevin Allen18

Expert 2290 points

Hi Kevin,

Is there a design reference scheme with DAS1205+F28379 or F2838X?

Many thanks~

0 Kevin Allen18 over 1 year ago in reply to Rhea Gao

TI__Mastermind 40825 points

Hi Rhea,

Sorry, I misunderstood your question in my initial reply and didn't look at the AD2S1205 device datasheet. You are wanting to interface with the digital side of the AD2S1205 device then?

The datasheet provides some reference below where a SPI interface is used. On the C2000 you could consider using the SPI and CLB modules to interface with the device. We do have some reference designs for interfacing with different Absolute Encoder types in this way.

Please see below for the references we have:

https://www.ti.com/tool/TIDM-1010

https://www.ti.com/tool/TIDM-1011

https://www.ti.com/tool/TIDM-1008

Best,

Kevin

0 Rhea Gao over 1 year ago in reply to Kevin Allen18

Expert 2290 points

Hi Kevin，

1. Could you please ask me again whether the clock input interface of the SDFM module of F28379 is compatible with I2C and SPI?

2. Are the F28379 and F2838x compatible in a 176pin package?

Many thanks~

0 Lori Heustess over 1 year ago in reply to Rhea Gao

TI__Guru* 90315 points

Hi Rhea,

We are looking into your questions and will reply back within a day.

Lori

0 Lori Heustess over 1 year ago in reply to Rhea Gao

TI__Guru* 90315 points

Rhea Gao said:
1. Could you please ask me again whether the clock input interface of the SDFM module of F28379 is compatible with I2C and SPI?

Looking at the datasheet, there doesn't seem to be any jitter or clock accuracy requirements for SDFM. If the same SPI or I2C is routed to the delta sigma modulators as well as looped back to the SDFM, there shouldn't be a challenge. They do need to maintain the setup hold time requirements which is now a function of the PCB layout. If the SPI or I2C is shared with some other communication interface, then again PCB related termination aspects

Note: ePWM is the most common way to clock the SDFM and delta sigma modulators. This is the tried and tested method.

There is a very informative application note on these details: https://www.ti.com/lit/TIDA033

Rhea Gao said:
2. Are the F28379 and F2838x compatible in a 176pin package?

There is a porting guide which describes the hardware changes from these two families: www.ti.com/lit/spracq1

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TMS320F28379D: rotary transformer