TCC720 Datasheet, PDF (23/143 Pages) List of Unclassifed Manufacturers – 32-bit RISC Microprocessor For Digital Media Player

TCC720
32-bit RISC Microprocessor for Digital Media Player
Dec. 16. 2002
DAI & CDIF
Preliminary Spec 0.51
3 DAI (Digital Audio Interface) & CDIF (CD-DSP Interface)
3.1 DAI
The TCC720 provides digital audio interface that complies with IIS (Inter-IC Sound). The DAI
has five input/output pins for IIS interface; MCLK, BCLK, LRCK, DAI, DAO. All DAI
input/output pins are multiplexed with GPIO pins; GPIO_B<21:25>. The MCLK is the system
clock pin that is used for CODEC system clock. The DAI provides 256fs, 384fs and 512fs as a
system clock. 256fs means that 256 times of sampling frequency fs. The BCLK is the serial bit
clock for IIS data exchange. The DAI can generate 64fs, 48fs and 32fs by dividing a system
clock. The polarity of BCLK can be programmed. The LRCK is the frame clock for the audio
channel Left and Right. The frequency of LRCK is the “fs” – sampling frequency. Generally, for
audio application – such as MP3 Player , CD player, the fs can be set to 8kHz, 16kHz,
11.05kHz, 24kHz, 32kHz, 44.1kHz and 48kHz. For supporting the wide range of sampling
frequency in audio application, the DCO function is very useful to generate a system clock.
Refer Chap. 7 for detail information. All three clocks are selectable as master or slave. The
DAI, DAO are the serial data input output pins respectively.
The DAI has two 8-word input/output buffers. The buffers can be read/written through the
DADI/DADO. The hidden buffer pointers automatically increment when user read/write from/to
the DADI/DADO. The maximum data word size is 24 bit. Data is justified to MSB of 32bits
and zeros are padded to LSB.
There are 2 types of interrupt from IIS; transmit done interrupt, receive done interrupt. The
transmit-done interrupt is generated when the 4 words are transferred successfully in the output
buffer. At this interrupt, user should fill another 4 more words into the other part of the output
buffer in the interrupt service routine (ISR). In this ISR routine, 4 consecutive stores of word
data to the DADO is needed – sequence is that the left channel is the first and right channel.
The receive-done interrupt is generated when the 4 words are received successfully in the input
buffer. At this interrupt, user should read 4 received words from the input buffer using 4
consecutive load instructions from the DADI – sequence is that the left channel is the first.
3-1