User's Manual

UniStone
Interfaces
Product Overview 17 T3130-8XV10PO5-7600, 2007-01-31
3.2 PCM Interface
The PCM interface is used to exchange synchronous data (usually audio) between
UniStone and the host as well as to connect e.g. an external audio codec or an external
DSP to UniStone. It can be configured as an industry standard PCM interface supporting
long and short frame synchronization, as an I2S interface
1)
or as an IOM-2 interface in
terminal mode with reduced capabilities.
The main features of the PCM interface are:
• Two bidirectional PCM channels
• Separate supply voltage (VDDPCM) for easy interfacing to other systems
• Support for all sample types defined in the Bluetooth specification
(Up to 16-bit linear samples and 8-bit A-law/µ-law compressed samples)
2)
• 8x32-bit FIFOs for each channel
• Programmable frame length
• Programmable frame signal length
• Programmable channel start positions
• Programmable idle level on PCMOUT
• Programmable low-power/inactive levels on all PCM pins
• Data word LSB justified or MSB justified with respect to frame signal
• Clock master/slave mode
• Frame master/slave mode
• Fractional divider for PCM clock generation
1)
Does not support variable word length. Hardware supports 16 or 24 bits. Current firmware supports 16 bits.
2)
The hardware supports data word lengths of up to 24 bits.