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STM32F4 with TDC7200 for ToF measurement

Question asked by Ananth C G on Jun 22, 2017
Latest reply on Jun 23, 2017 by Ananth C G


I am using TI's TDC7200 with STM32F407. The interface is SPI. I am able to read and write into the TDC7200 registers (CONFIG1 and CONFIG2) over SPI without any problem. As per the TDC7200 Datasheet, upon writing a 0x01 into the CONFIG1 register of the TDC7200, a TRIGGER signal will be set by the TDC7200, which will be reset only after a START signal is received by the TDC7200.


The issue is that after I write a 0x01 or 0x03 into CONFIG1 register, I don't get any TRIGGER signal. I am able to read back the same CONFIG1 register and see that the register value has changed to whatever I have configured. The values of other registers are kept default and only CONFIG1 register is modified. I have checked the CLOCK - its 8MHz, SPI CLOCK - SCLK is 8MHz, and there is a LOW to HIGH on ENABLE Pin at the beginning as well (as per the datasheet). I have monitored the TRIGGER pin of the TDC using Oscilloscope, it doesn't go HIGH.


For my purpose, I am not using TDC1000. Both TRIGGER and INTB of TDC7200 are connected to MCU (STM32F4) as interrupts. The purpose is to send START (followed by STOP) signals to the TDC7200 upon receiving TRIGGER interrupt, and then get INTB interrupt from TDC7200 after STOP Signal and then proceed for calculations of TOF.


What could be the problem ? Why am I not able to get TRIGGER interrupt from TDC7200 ? Is there something that I have missed ? Can someone help ?


The Measurement Sequence, as described in the TDC7200 datasheet is as below:

For reference I have attached the Datasheet of TDC7200 as well.

Thanks in advance.