CM6533-N Datasheet, PDF (47/60 Pages) C-Media Electronics – USB 2.0 Full-Speed compliant

CM6533,CM6533N,CM6533X1,CM6533DH
USB Audio Chip
6.11 Arbitrary Sine-tone Generator
There are four (4) memory banks to store user defined waveform in CM6533/CM6533N/CM6533X1/CM6533DH
design. This function would generate waveform data that is desired to be heard from earphones. For example
when function keys were pressed or do other operations. User can predefine two different waveforms with 96K and
88.2K sampling rates and stores it in corresponding memory banks. The waveform data format must comply with
the following specifications:
1. 16 bits PCM with 2’s complement
2. First word must define waveform length (Length[9:0]= {byte1[2:0], byte0[7:0]})
3. Waveform length must less than 2046
4. Four memory banks
Bank1: 0x6000~0x67FF (Length: 0x6000~0x6001, Waveform data 0x6002~0x67FF)
Bank2: 0x6800~0x6FFF (Length: 0x6800~0x6801, Waveform data 0x6802~0x6FFF)
Bank3: 0x7000~0x77FF (Length: 0x7000~0x7001, Waveform data 0x7002~0x77FF)
Bank4: 0x7800~0x7FFF (Length: 0x7800~0x7801, Waveform data 0x7802~0x7FFF)
Generating sine-tone is based on a look-up table and the step size of look-up table for different sampling rates
would be adjusted automatically.
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Rev.1.6
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