CM6533DH datasheet(47/60 Pages) CMEDIA

47 / 60 page

CM6533,CM6533N,CM6533X1,CM6533DH

USB Audio Chip

Page 47 / 60

www.cmedia.com.tw

Rev.1.6

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.

CM6533DH Datasheet(PDF) 47 Page - C-Media Electronics