LPC_SC->PCONP |= (1 << 27);	//power up I2S

// ????? LPC_SC->PCLKSEL1  |= (3 << 22); // as an example CCLK:8 = 96MHz:8=12MHz;

LPC_SC->PINSEL0 |= (1 << 14); // I2SRX_CLK  ; P0[23] is Mbed Pin 15
LPC_SC->PINSEL0 |= (1 << 16); // I2SRX_WS   ; P0[24] is Mbed Pin 16
LPC_SC->PINSEL0 |= (1 << 18); // I2SRX_SDA  ; P0[25] is Mbed Pin 17

LPC_SC->I2SRXMODE = 0x0; // Typical Receiver Slave Mode ,page 486 LPC17xx handbook

LPC_SC->I2SDAI |= (3 << 0); // wordwidth 32 bit data
LPC_SC->I2SDAI |= (0 << 2);  // Set Stereo
LPC_SC->I2SDAI |= (1 << 5);  // set Slave Mode

LPC_SC->I2SRXBITRATE = 0x1F; // is 63, because RX_MCLK(6,144Mbit/s) : (63+1) = 96kHz 

LPC_SC->I2SIRQ |= (1 << 0);  // Enable I2S receive interrupt

Hello, I have an application, where I want to receive data from an external ADC. In this configuration, I will use the mbed in "Slave mode" and I will you use the rx channel to get the data. The LPC17xx user manual shows this configuration in Chapter 20 "Fig. 110. Typical receiver slave mode". So I will receive the I2SRX_CLK from the ADC. In my case it is 6,144Mbit/s for a frame of 2*32bit with a sampling rate of 96kHz. **My question:** Do I have to setup the PCLKSEL1 register ? The manual requires it for the basic setup. I think not, since the bit clock will be provided by the ADC, which is setup as Master. Thanks for any advice. Michael Code extract: <<code>> LPC_SC->PCONP |= (1 << 27); //power up I2S // ????? LPC_SC->PCLKSEL1 |= (3 << 22); // as an example CCLK:8 = 96MHz:8=12MHz; LPC_SC->PINSEL0 |= (1 << 14); // I2SRX_CLK ; P0[23] is Mbed Pin 15 LPC_SC->PINSEL0 |= (1 << 16); // I2SRX_WS ; P0[24] is Mbed Pin 16 LPC_SC->PINSEL0 |= (1 << 18); // I2SRX_SDA ; P0[25] is Mbed Pin 17 LPC_SC->I2SRXMODE = 0x0; // Typical Receiver Slave Mode ,page 486 LPC17xx handbook LPC_SC->I2SDAI |= (3 << 0); // wordwidth 32 bit data LPC_SC->I2SDAI |= (0 << 2); // Set Stereo LPC_SC->I2SDAI |= (1 << 5); // set Slave Mode LPC_SC->I2SRXBITRATE = 0x1F; // is 63, because RX_MCLK(6,144Mbit/s) : (63+1) = 96kHz LPC_SC->I2SIRQ |= (1 << 0); // Enable I2S receive interrupt <</code>>