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TMS320F28375S: Expanding the available analog inputs for more signals.

Asad Hameed
Intellectual 735 points

Part Number: TMS320F28375S
Other Parts Discussed in Thread: TMS320F28384S

In our product design with the 176 pin TMS320F28375s DSP we are facing limitation with the number of available analog inputs. We are unable to map all the required analog signals to the available 20 analog pins. We are looking for a efficient analog expansion that requires minimum communication overhead from the main CPU. Ideally it should be a sequential sampling device that samples analog inputs one after another and then streams the results over some serial interface available on the TMS320F28375S DSP.  On the DSP side there should be a DMA based serial data read into some buffers. The main CPU can then process data whenever it needs. Please let me know if there is any such or better solution available.

  • 0
    Intellectual 735 points

    Please note that the expanded analog readings are not controls related so precise sampling time requirements are not there. These are slow readings such temperatures etc. The control inputs will be routed directly to the DSP analog inputs.

  • 0
    TI__Guru** 119680 points

    you can look at the 337-ball BGA or look at 

    TMS320F28384S

  • +1 in reply to ChrisClearman
    Intellectual 735 points

    Actually the total ADC requirements is a big count i.e. 38 in total . We are routing 14 fast conversions relating to controls on our main DSP leaving a room for two additional inputs for future requirements. We have selected a low cost microcontroller (under 2 dollar chip) in 44 pin package having 28 analog inputs. The remaining 24 slow conversions will be routed to this microcontroller.  This microcontroller will do all the analog conversions and then stream to our TMS320F2837x DSP  over UART or SPI. On the DSP side we intend to setup a DMA based serial data read to remove serial communication overhead from the main processor. Please let me know if you have better idea.