Texas Instruments TLV320AIC23 manual I2C Adjust, Clock Select Button, Frequency Display Areas

I2C Adjust

4.4.18Clock Select Button

Clicking the Clock Select button opens a panel that allows selection of master clock speed and ADC and DAC sampling rates (see Section 4.6.11). (Do clock selections correspond to sampling rate register bits?)

4.4.19 Frequency Display Areas

In the lower right corner of the main panel are two frequency displays. The one on the left shows the master clock frequency MCLK in megaHertz; the one on the right shows the DAC sampling frequency in kiloHertz.

4.5 I2C Adjust

The I2C commands are generated on the parallel port using a method referred to as bit-banging. Because Windows does not have readily accessible timers down into the microseconds, the I2C clocks are done using C++ for-loops to create the delay. The number of executions of the for-loop is calibrated initially when the program is started. This initial calibration sets SCL to 100 kHz. The looping variable in the for-loop can be changed using the SCL period A and

"buttons, which only become active after clicking the Fine Adjust button. To see the result of changing this variable, requires capturing the SCL output on a storage oscilloscope. The program recalibrates SCL to 100 kHz if the RECALIBRATE button is pressed.

Figure 4–3. I2C Adjust

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