ADS1201: Transmit MOUT and MCLK thru a fiber optic device

Hi,

I am interested in this topic and I am new to this subject. How does the internal oscillator eliminate the delay? Do you have  a part recommendation that will work when the processor is on a different board wrt to the modulator and the data needs to be transmitted through fiber optic? The sensed signal is 500 Hz and the clock frequency does not need to be high (around 100 kHz is good). The analog input has a +/- 1 V range.

Thanks,

Hi Lakshmi,

Modulators that have an internal oscillator would send both clock and data synchronously to the digital filter - FPGA, mCU, DSP, etc.  Whatever the transmission line is from the modulator to the processor, the clock and data remain in phase.  There is still some delay, but the signals remain synchronous to each other when it reaches the filter module.

If the modulator uses an external clock, there will be delay on the clock from the processor to the modulator and then a delay on the data from the modulator back to the processor.  This creates a phase delay between the two signals as they enter the digital filter block.  Depending on the setup and hold requirements at the processor side, you could introduce errors in reading the data.  Our newer modulators use minimum clock speeds of 10-20MHz, so these delays can cause problems.  The ADS1201 device, running with 100kHz clock, would be more forgiving of transmission delays.  In the end, once the transmission delay approaches 1/2 clock cycle, you could start to experience data loss.

Hi Tom,

Thanks for the explanation! Where can I find information about programming the ADS1201 to work with the C2000 processor?

-Lakshmi

Hi Lakshmi,

Since the ADS1201 has nothing to program (no internal registers), you would need to start with the C2000 datasheet/SDFM peripheral user manual.  Which processor variant are you using?