How can I select the Left/Right channel when writing data to the HT82V731?
When the WS pin is set high, the Left channel is selected and when the WS pin is low, the Right channel is selected.
For the HT82V731, why does a code of 0000h not give an output voltage of 0V?
This device is normally used to output music frequencies. The output voltage range of the D/A will normally fluctuate around some centre voltage. Because the HT82V731 uses 2's compliment input values, therefore with VDD = 5V, a 0000H input will give a centre voltage of 2.5V. An input value of 7FFFH, which is the largest value, will give an approximate output voltage of 3.7V. For a 8000H input value, which is the smallest value, an output voltage of approximately 1.3V will be provided. The average value between the smallest and largest value is 2.5V.
Is it necessary to send a complete 16 bits frame for each channel?
Yes. If the data length is shorter than 16 bits, 0 stuffing is needed. For single-channel applications, the unused channel should be filled with data, however, the timing could be 50 kHz faster than normal.