A software library that allows you to control an I²S or TDM (time division multiplexed) bus via xCORE ports. I²S and TDM are digital data streaming interfaces particularly appropriate for transmission of audio data. The components in the library are controlled via C using the XMOS multicore extensions (xC) and can either act as I²S master, TDM master or I²S slave.

• I²S master, TDM master and I²S slave modes.
• Handles multiple input and output data lines.
• Support for standard I²S, left justified or right justified data modes for I²S.
• Support for multiple formats of TDM synchronization signal.
• Efficient "frame-based" versions of I²S master and slave allowing use of processor cycles in between I2S signal handling.
• Sample rate support up to 192kHz or 768kHz for "frame-based" versions.
• Up to 32 channels in/32 channels out (depending on sample rate and protocol).

.. resusage::

  * - configuration: |I2S| Master (frame-based)
    - globals:   out buffered port:32 p_dout[2] = {XS1_PORT_1D, XS1_PORT_1E};
                 in buffered port:32 p_din[2]  = {XS1_PORT_1I, XS1_PORT_1K};
                 port p_mclk  = XS1_PORT_1M;
                 out port p_bclk  = XS1_PORT_1A;
                 out buffered port:32 p_lrclk = XS1_PORT_1C;
                 clock mclk = XS1_CLKBLK_1;
                 clock bclk = XS1_CLKBLK_2;
    - locals: interface i2s_frame_callback_if i;
    - fn: i2s_frame_master(i, p_dout, 2, p_din, 2, p_bclk, p_lrclk, p_mclk, bclk);
    - pins: 3 + data lines
    - ports: 3 x (1-bit) + data lines
    - cores: 1
    - target: XCORE-200-EXPLORER
  * - configuration: |I2S| Master
    - globals:   out buffered port:32 p_dout[2] = {XS1_PORT_1D, XS1_PORT_1E};
                 in buffered port:32 p_din[2]  = {XS1_PORT_1I, XS1_PORT_1K};
                 port p_mclk  = XS1_PORT_1M;
                 out buffered port:32 p_bclk  = XS1_PORT_1A;
                 out buffered port:32 p_lrclk = XS1_PORT_1C;
                 clock mclk = XS1_CLKBLK_1;
                 clock bclk = XS1_CLKBLK_2;
    - locals: interface i2s_callback_if i;
    - fn: i2s_master(i, p_dout, 2, p_din, 2, p_bclk, p_lrclk, bclk, mclk);
    - pins: 3 + data lines
    - ports: 3 x (1-bit) + data lines
    - cores: 1
    - target: XCORE-200-EXPLORER
  * - configuration: |I2S| Slave (frame-based)
    - globals:   out buffered port:32 p_dout[2] = {XS1_PORT_1D, XS1_PORT_1E};
                 in buffered port:32 p_din[2]  = {XS1_PORT_1I, XS1_PORT_1K};
                 port p_mclk  = XS1_PORT_1M;
                 in port p_bclk  = XS1_PORT_1A;
                 in buffered port:32 p_lrclk = XS1_PORT_1C;
                 clock bclk = XS1_CLKBLK_2;
    - locals: interface i2s_frame_callback_if i;
    - fn: i2s_frame_slave(i, p_dout, 2, p_din, 2, p_bclk, p_lrclk, bclk);
    - pins: 2 + data lines
    - ports: 2 x (1-bit) + data lines
    - cores: 1
    - target: XCORE-200-EXPLORER
  * - configuration: |I2S| Slave
    - globals:   out buffered port:32 p_dout[2] = {XS1_PORT_1D, XS1_PORT_1E};
                 in buffered port:32 p_din[2]  = {XS1_PORT_1I, XS1_PORT_1K};
                 port p_mclk  = XS1_PORT_1M;
                 in port p_bclk  = XS1_PORT_1A;
                 in buffered port:32 p_lrclk = XS1_PORT_1C;
                 clock bclk = XS1_CLKBLK_2;
    - locals: interface i2s_callback_if i;
    - fn: i2s_slave(i, p_dout, 2, p_din, 2, p_bclk, p_lrclk, bclk);
    - pins: 2 + data lines
    - ports: 2 x (1-bit) + data lines
    - cores: 1
    - target: XCORE-200-EXPLORER
  * - configuration: TDM Master
    - globals:   out buffered port:32 p_dout[2] = {XS1_PORT_1D, XS1_PORT_1E};
                 in buffered port:32 p_din[2]  = {XS1_PORT_1I, XS1_PORT_1K};
                 out buffered port:32 p_fsync = XS1_PORT_1C;
                 clock bclk = XS1_CLKBLK_2;
    - locals: interface i2s_callback_if i;
    - fn: tdm_master(i, p_fsync, p_dout, 2, p_din, 2, bclk);
    - pins: 2 + data lines
    - ports: 2 x (1-bit) + data lines
    - cores: 1
    - target: XCORE-200-EXPLORER

.. libdeps::

The library supports both "sample-based" and "frame-based" versions of I²S master and slave. The "frame-based" versions are recommended for new designs and support higher I²S channel counts and rates. In addition, the number of callbacks to pass data to and from the I²S handler task are reduced. "Frame-based" I²S pass an array of channels per sample period whereas "sample-based" versions make a callback per channel within a sample period. The "frame-based" callbacks are all grouped together allowing the user side to make maximum use of the MIPS between I²S frames. For example, a 48kHz (20.83us) I²S interface supports a total of 19us processing per sample period, in any order, across the callbacks. The older "sample-based" versions are currently maintained to provide compatibility with existing code examples.

The following application notes use this library:

• AN00162 - Using the I²S library