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TMDXMDKPO8328 Pulse Oximeter on FPGA

Borja Menendez
Prodigy 20 points
Other Parts Discussed in Thread: TMS320C5515, DAC7573

Hello,

I'm trying to work with the pulse oximeter mentioned on the subject. I'm codifying on Windows 7 with Xilinx 13.1 in VHDL, simulating with Modelsim Student Edition 10.1 and verifying data transmit with GoLogic2 (version 5.31). The problem I have is I'm doing (or I think I'm doing) the right things in the FPGA and it doesn't works. The TMS320C5515 DSP works as you can see in the following image:

And my FPGA, programming by me, works as follow:

As you can see, it's practically the same (ok, the I2C_SCL is always running during the R_SWT / IR_SWT, but I think it's not relevant while you transmit the other signals correctly) but it doesn't works and I don't know why. I'm trying to follow the documentation as much as I can, but there are many things I don't understand (the first of all is that DSP doesn't follow documentacion, i.e. R / IR pulses aren't active 450 us but 520-530-540 us) and, also, I'm trying to do a mix between documentation and DSP.

Can anyone help me with my project? I'm desperate trying to light the LED of the finger SpO2 probe.

Thank you.

  • 0
    TI__Guru**** 180961 points

    Hi Borja,

    The TMDXMDKPO8328 is supported by our C5000 applications team.  I'll move your post to their forum.

  • 0
    TI__Mastermind 30120 points

    Hi Borja,

    Any progress in getting the LED to light up?

    The R_SWT and IR_SWT signals look the same in both waveforms... so the switching should be okay.

    Can you compare the DAC0_A and DAC0_B voltages when running with DSP vs running with FPGA?

    Are you getting expected I2C communication between your FPGA and the DAC7573?

    Refer to the I2C Interface of DAC7573: http://www.ti.com/lit/ds/symlink/dac7573.pdf

    Hope this helps,
    Mark

  • 0 in reply to Mark M
    Prodigy 20 points

    Hi Mark,

    I still can't get the LED to light up. Running with DSP, the voltages in DAC0_A and DAC0_B are around 0.130V, but with FPGA are around 3.7V! Would you know what I am doing wrong? I'm very surprised...

    Between my FPGA and the DAC7573 (thanks for the reference to its datasheet) there is communication: the FPGA tell the DAC to put some values to its current and voltage (to the LEDs) and the DAC reply to the FPGA with the values that it is getting from the finger probe.

    I'm supplying the pulse oximeter with its three points of 1.8V, 3.3V and 5V, it is all correct? Do I need to supply with these three voltages of reference to the pulse oximeter or do I only need one point (3.3V)?

    Thank you for your help,

    Borja.