SLAA126B April   2001  – September 2018 MSP430F149 , MSP430F149 , TLC3544 , TLC3544 , TLC3548 , TLC3548

 

  1.   Interfacing the TLC3544 or TLC3548 ADC to the MSP430F149 MCU
    1.     Trademarks
    2. 1 Introduction
    3. 2 TLC3544/48 Evaluation Module
    4. 3 Serial Interface
      1. 3.1 Chip Select (CS)
      2. 3.2 Serial Data Input (SDI)
      3. 3.3 Serial Data Output Pin (SDO)
      4. 3.4 Serial Clock Pin (SCLK)
    5. 4 Control and I/O Pins
      1. 4.1 Conversion Start (CSTART)
      2. 4.2 Frame Sync (FS)
      3. 4.3 End of Conversion/Interrupt (EOC/INT)
      4. 4.4 Device Pinout
    6. 5 ADC Initialization and Operation
      1. 5.1 Initializing the ADC
      2. 5.2 Operating the ADC
      3. 5.3 EOC or INT
    7. 6 MSPF149 Code Example
    8. 7 References

4.3 End of Conversion/Interrupt (EOC/INT)

The EOC/INT pin is a programmable output, which indicates the end of conversion (EOC) or acts as an interrupt (INT) to host processor. When programmed as EOC, the output goes from a high-to-low state at the end of the sampling period and returns to a high state when the conversion process is complete. In other words, EOC indicates that the ADC is busy doing a conversion.

When programmed as INT, the pin goes low after the conversion is complete, and stays low until reset by the falling edge of CS or CSTART. A rising edge on the FS input can also clear INT.

The assembly code for this application report uses the EOC/INT pin to signal the processor that the conversion process has completed. The configuration/channel selection information is transmitted to the ADC as two bytes. The processor then enters a loop that transmits zeros or dummy data until it receives an interrupt from the ADC.