Use the TLV320 with in-built I2S object to stream audio data from an SD Card and send it to the TLV320 CODEC for audio playback
Dependencies: I2SSlave mbed TLV320
I2SSlave/I2SSlave.cpp
- Committer:
- d_worrall
- Date:
- 2011-08-05
- Revision:
- 0:3d6892f6384f
File content as of revision 0:3d6892f6384f:
/****************************************************** * I2SSlave.cpp: I2S port abstraction library cpp file for NXP LPC1768 * * Written by: * mbed Team - 15th July 2011 * Daniel Worrall * * History * version 1.31 ******************************************************/ #include "I2SSlave.h" /*Global Functions*/ FunctionPointer akjnh3489v8ncv; extern "C" void I2S_IRQHandler(void){ //this is a very special function so can remain outside akjnh3489v8ncv.call(); } /****************************************************** * Function name: I2SSlave * * Description: class constructor * * Parameters: PinName tx_sda, PinName tx_ws, PinName clk, PinName rx_sda, PinName rx_ws * Returns: none ******************************************************/ //Constructor I2SSlave::I2SSlave(PinName tx_sda, PinName tx_ws, PinName clk, PinName rx_sda, PinName rx_ws){ storePins_(tx_sda, tx_ws, clk, rx_sda, rx_ws); format(16, STEREO); //this also invokes initialize so no need to call it twice } //Public functions /****************************************************** * Function name: format() * * Description: sets the bit length for writing and stereo or mono mode * * Parameters: int bit, bool mode * Returns: none ******************************************************/ void I2SSlave::format(int bit, bool mode){ bit_ = bit; mode_ = mode; initialize_(tx_sda_, tx_ws_, clk_, rx_sda_, rx_ws_); } /****************************************************** * Function name: write() * * Description: load buffer to write to I2S port * * Parameters: long *buffer * Returns: none ******************************************************/ void I2SSlave::write(int* buffer, int from, int length){ int to = from + length; for(int i = from; i < to; ++i){ LPC_I2S->I2STXFIFO = buffer[i]; } } /****************************************************** * Function name: start() * * Description: attach streamOut_ function to ticker interrupt * * Parameters: none * Returns: none ******************************************************/ void I2SSlave::start(int mode){ switch(mode){ case(0): LPC_I2S->I2SIRQ |= (0 << 0); //disable receive interrupt LPC_I2S->I2SIRQ |= (0 << 1); //disable transmit interrupt break; case(1): LPC_I2S->I2SIRQ |= (0 << 0); //disable receive interrupt LPC_I2S->I2SIRQ |= (1 << 1); //enable transmit interrupt LPC_I2S->I2SIRQ |= (0 << 16); //set I2STXFIFO depth to 0 words break; case(2): LPC_I2S->I2SIRQ |= (1 << 0); //enable receive interrupt LPC_I2S->I2SIRQ |= (0 << 1); //disable transmit interrupt LPC_I2S->I2SIRQ |= (4 << 8); //set I2SRXFIFO depth to 4 words break; case(3): LPC_I2S->I2SIRQ |= (1 << 0); //enable receive interrupt LPC_I2S->I2SIRQ |= (4 << 8); //set I2SRXFIFO depth to 4 words LPC_I2S->I2SIRQ |= (1 << 1); //enable transmit interrupt LPC_I2S->I2SIRQ |= (0 << 16); //set I2STXFIFO depth to 0 words break; default: break; } NVIC_SetPriority(I2S_IRQn, 0); NVIC_EnableIRQ(I2S_IRQn); //enable I2S interrupt in the NVIC } /****************************************************** * Function name: stop() * * Description: detach streamOut_ from ticker * * Parameters: none * Returns: none ******************************************************/ void I2SSlave::stop(void){ NVIC_DisableIRQ(I2S_IRQn); } /****************************************************** * Function name: read() * * Description: reads FIFORX buffer into [int32_t rxBuffer[8]] * * Parameters: none * Returns: none ******************************************************/ void I2SSlave::read(void){ rxBuffer[0] = LPC_I2S->I2SRXFIFO; rxBuffer[1] = LPC_I2S->I2SRXFIFO; rxBuffer[2] = LPC_I2S->I2SRXFIFO; rxBuffer[3] = LPC_I2S->I2SRXFIFO; } /****************************************************** * Function name: status_() * * Description: Read I2SSTATE register * * Parameters: none * Returns: int ******************************************************/ int I2SSlave::status(void){ return LPC_I2S->I2SSTATE; } //Private functions /****************************************************** * Function name: initialize() * * Description: initialises I2S port * * Parameters: PinName tx_sda, PinName tx_ws, PinName clk, PinName rx_sda, PinName rx_ws * Returns: 0 = successful initialisation -1 = initialisation failure ******************************************************/ int I2SSlave::initialize_(PinName tx_sda, PinName tx_ws, PinName clk, PinName rx_sda, PinName rx_ws){ setPins_(tx_sda, tx_ws, clk, rx_sda, rx_ws); //designate pins LPC_SC->PCONP |= (1 << 27); //configure input/output register format_(bit_, mode_); //set mbed as SLAVE LPC_I2S->I2SDAO |= (1 << 5); LPC_I2S->I2SDAI |= (1 << 5); //clock mode setClocks_(4); //set slave mode modeConfig_(); //set receiver mode LPC_I2S->I2SRXMODE |= (1 << 1); //slave mode LPC_I2S->I2STXRATE = 0; LPC_I2S->I2SRXRATE = 0; //Start LPC_I2S->I2SDAO |= (0 << 3); LPC_I2S->I2SDAI |= (0 << 3); LPC_I2S->I2SDAO |= (0 << 4); LPC_I2S->I2SDAI |= (0 << 4); LPC_I2S->I2SDAO |= (0 << 15); return 0; } /****************************************************** * Function name: setClocks_() * * Description: Set the division setting on the internal clocks * * Parameters: int divideBy * Returns: nothing ******************************************************/ void I2SSlave::setClocks_(int divideBy){ switch(divideBy){ case 1: LPC_SC->PCLKSEL1 |= (1 << 22); LPC_SC->PCLKSEL1 |= (0 << 23); break; case 2: LPC_SC->PCLKSEL1 |= (0 << 22); LPC_SC->PCLKSEL1 |= (1 << 23); break; case 4: LPC_SC->PCLKSEL1 |= (0 << 22); LPC_SC->PCLKSEL1 |= (0 << 23); break; case 8: LPC_SC->PCLKSEL1 |= (1 << 22); LPC_SC->PCLKSEL1 |= (1 << 23); break; default: break; } } /****************************************************** * Function name: setPins_() * * Description: set external pin configuration * * Parameters: PinName tx_sda, PinName tx_ws, PinName clk, PinName rx_sda, PinName rx_ws * Returns: none ******************************************************/ void I2SSlave::setPins_(PinName tx_sda, PinName tx_ws, PinName clk, PinName rx_sda, PinName rx_ws){ if(rx_ws == p29){ LPC_PINCON->PINSEL0 |= (1 << 10); //set p29 as receive word select line } else { LPC_PINCON->PINSEL1 |= (2 << 16); //set p16 as receive word select line } if(rx_sda == p8){ LPC_PINCON->PINSEL0 |= (1 << 12); //set p8 as receive serial data line } else { LPC_PINCON->PINSEL1 |= (2 << 18); //set p17 as receive serial data line } LPC_PINCON->PINSEL0 |= (1 << 14); //set p7 as transmit clock line (only one of these) LPC_PINCON->PINSEL0 |= (1 << 16); //set p6 as word select line (only one of these) LPC_PINCON->PINSEL0 |= (1 << 18); //set p5 as transmit serial data line (only one of these) LPC_PINCON->PINSEL0 |= (0 << 8); //clear rx_clk } /****************************************************** * Function name: format_() * * Description: sets the bit length for writing and stereo or mono mode * * Parameters: int bit, bool mode * Returns: none ******************************************************/ void I2SSlave::format_(int bit, bool mode){ uint32_t bps= ((bit+1)*8)-1; LPC_I2S->I2SDAO &= (0x00 << 6); LPC_I2S->I2SDAO |= (bps << 6); //set bit length switch(bit){ case 8: LPC_I2S->I2SDAO &= 0xfffffffc; break; case 16: LPC_I2S->I2SDAO &= (0 << 1); LPC_I2S->I2SDAO |= (1 << 0); break; case 32: LPC_I2S->I2SDAO &= (0 << 1); LPC_I2S->I2SDAO |= (3 << 0); break; default: break; } //set audio mode if(mode == STEREO){ LPC_I2S->I2SDAO |= (0 << 2); } else { LPC_I2S->I2SDAO |= (1 << 2); } //set transmitter and receiver setting to be the same LPC_I2S->I2SDAI &= (0x00 << 6); LPC_I2S->I2SDAI |= (bps << 6); //set bit length switch(bit){ case 8: LPC_I2S->I2SDAI &= 0xfffffffc; break; case 16: LPC_I2S->I2SDAI &= (0 << 1); LPC_I2S->I2SDAI |= (1 << 0); break; case 32: LPC_I2S->I2SDAI &= (0 << 1); LPC_I2S->I2SDAI |= (3 << 0); break; default: break; } //set audio mode if(mode == STEREO){ LPC_I2S->I2SDAI |= (0 << 2); } else { LPC_I2S->I2SDAI |= (1 << 2); } } /****************************************************** * Function name: modeConfig_() * * Description: Set slave mode * * Parameters: none * Returns: none ******************************************************/ void I2SSlave::modeConfig_(void){ LPC_I2S->I2STXMODE |= (0x0 << 0); LPC_I2S->I2SRXMODE |= (0x0 << 0); } /****************************************************** * Function name: storePins_() * * Description: set external pin configuration * * Parameters: PinName tx_sda, PinName tx_ws, PinName clk, PinName rx_sda, PinName rx_ws * Returns: none ******************************************************/ void I2SSlave::storePins_(PinName tx_sda, PinName tx_ws, PinName clk, PinName rx_sda, PinName rx_ws){ tx_sda_ = tx_sda; tx_ws_ = tx_ws; clk_ = clk; rx_sda_ = rx_sda; rx_ws_ = rx_ws; }