嵌入式电子工程师资料合集 9.FPGA

/* * ip_functions.c * * Contains all functions which pertain to setup and use of IP periperals. */ #include "adventures_with_ip.h" #include "audio.h" /* ---------------------------------------------------------------------------- * * lms_filter() * * ---------------------------------------------------------------------------- * * This function adds a tonal noise component to the sampled audio from the * audio codec by passing a step size to the input of an NCO component in the * PL. A sinusoidal signal is received back from the NCO which is then scaled * and added to the sampled audio. The audio + noise sample can then be * adaptively filtered using an LMS filter in the PL. The resulting audio, * filtered or not, is then output to the audio codec. * * The main menu can be accessed by entering 'q' on the keyboard. * ---------------------------------------------------------------------------- */ void lms_filter() { u32 nco_in, nco_out, in_left, in_right, out_left, out_right, step, \ prevL, prevR, prevTone, temp; /* Read step size value from DIP switches */ step = XGpio_DiscreteRead(&Gpio, SWITCH_CHANNEL); /* Write step size value to the LEDs */ Xil_Out32(LED_BASE, step); /* Scale the step size */ nco_in = step; xil_printf("Step = %d, nco_in = %d\r\n",step, nco_in); while (!XUartPs_IsReceiveData(UART_BASEADDR)){ /* Input step size to the NCO core */ XNco_Set_step_size_V(&Nco, nco_in); /* Receive sinusoidal sample from NCO core */ nco_out = XNco_Get_sine_sample_V(&Nco); if(nco_out!=prevTone) { /* New sinusoidal sample? */ temp = nco_out; } /* Sample L+R audio from the codec */ in_left = Xil_In32(I2S_DATA_RX_L_REG); in_right = Xil_In32(I2S_DATA_RX_R_REG); /* -------------------------------------------------------------------------------- * * --------------------------------- LEFT CHANNEL --------------------------------- * * -------------------------------------------------------------------------------- */ if(in_left != prevL) /* New left sample? */ { /* Add noise component to the L+R audio samples */ out_left = (temp + in_left); Xil_Out32(LMS_D, out_left >> SCALE); // Input audio+noise as desired signal Xil_Out32(LMS_X, temp >> SCALE); // Input noise as input Xil_Out32(LMS_STROBE, 0x01); // Stobe LMS to signal inputs are finished /* If any button is pressed */ if(XGpio_DiscreteRead(&Gpio, BUTTON_CHANNEL)>0){ /* Wait until output data is ready */ out_left = (Xil_In32(LMS_E) << (SCALE-1)); // Output filtered audio } /* Output audio to the codec */ Xil_Out32(I2S_DATA_TX_L_REG, out_left); } /* -------------------------------------------------------------------------------- * * --------------------------------- RIGHT CHANNEL -------------------------------- * * -------------------------------------------------------------------------------- */ if(in_right != prevR) /* New right sample? */ { /* Add scaled noise component to the L+R audio samples */ out_right = (temp + in_right); Xil_Out32(LMS_D, out_right >> SCALE); // Input audio+noise as desired signal Xil_Out32(LMS_X, temp >> SCALE); // Input noise as input Xil_Out32(LMS_STROBE, 0x01); // Stobe LMS to signal inputs are finished /* If any button is pressed */ if(XGpio_DiscreteRead(&Gpio, BUTTON_CHANNEL)>0){ out_right = (Xil_In32(LMS_E) << (SCALE-1)); // output filtered audio } /* Output audio to the codec */ Xil_Out32(I2S_DATA_TX_R_REG, out_right); } /* Update previous input values */ prevL = in_left; prevR = in_right; prevTone = nco_out; /* If the DIP switch values have changed, break from while * loop to allow the step size value to update. */ if(step != XGpio_DiscreteRead(&Gpio, SWITCH_CHANNEL)) break; } // while /* If input from the terminal is 'q', then return to menu. * Else, continue. */ if(XUartPs_ReadReg(UART_BASEADDR, XUARTPS_FIFO_OFFSET)=='q') menu(); else lms_filter(); } // LMS filtering /* ---------------------------------------------------------------------------- * * tonal_noise() * * ---------------------------------------------------------------------------- * * This function adds a tonal noise component to the sampled audio from the * audio codec by passing a step size to the input of an NCO component in the * PL. A sinusoidal signal is received back from the NCO which is then scaled * and added to the sampled audio. The audio + noise sample is then sent to * the audio codec for output. * * The main menu can be accessed by entering 'q' on the keyboard. * ---------------------------------------------------------------------------- */ void tonal_noise(void) { u32 nco_in, nco_out, in_left, in_right, out_left, out_right, step, temp; /* Read step size value from DIP switches */ step = XGpio_DiscreteRead(&Gpio, SWITCH_CHANNEL); /* Write step size value to the LEDs */ Xil_Out32(LED_BASE, step); /* Scale the step size */ nco_in = step; xil_printf("Step = %d, nco_in = %d\r\n",step, nco_in); while (!XUartPs_IsReceiveData(UART_BASEADDR)){ /* Input scaled step size to the NCO core */ XNco_Set_step_size_V(&Nco, nco_in); /* Receive sinusoidal sample from NCO core */ nco_out = XNco_Get_sine_sample_V(&Nco); temp = nco_out; /* Sample L+R audio from the codec */ in_left = Xil_In32(I2S_DATA_RX_L_REG); in_right = Xil_In32(I2S_DATA_RX_R_REG); /* Add scaled noise component to the L+R audio samples */ out_left = temp + in_left; out_right = temp + in_right; /* Output corrupted audio to the codec */ Xil_Out32(I2S_DATA_TX_L_REG, out_left); Xil_Out32(I2S_DATA_TX_R_REG, out_right); /* If the DIP switch values have changed, break from while * loop to allow the step size value to update. */ if(step != XGpio_DiscreteRead(&Gpio, SWITCH_CHANNEL)) break; } // while /* If input from the terminal is 'q', then return to menu. * Else, continue. */ if(XUartPs_ReadReg(UART_BASEADDR, XUARTPS_FIFO_OFFSET) == 'q') menu(); else tonal_noise(); } // tonal_noise() /* ---------------------------------------------------------------------------- * * audio_stream() * * ---------------------------------------------------------------------------- * * This function performs audio loopback streaming by sampling the input audio * from the codec and then immediately passing the sample to the output of the * codec. * * The main menu can be accessed by entering 'q' on the keyboard. * ---------------------------------------------------------------------------- */ void audio_stream(){ //int index = 0; u32 in_left, in_right; while (!XUartPs_IsReceiveData(UART_BASEADDR)){ // Read audio input from codec in_left = Xil_In32(I2S_DATA_RX_L_REG); in_right = Xil_In32(I2S_DATA_RX_R_REG); // Write audio input to codec Xil_Out32(I2S_DATA_TX_L_REG, in_left); Xil_Out32(I2S_DATA_TX_R_REG, in_right); } /* If input from the terminal is 'q', then return to menu. * Else, continue streaming. */ if(XUartPs_ReadReg(UART_BASEADDR, XUARTPS_FIFO_OFFSET) == 'q') menu(); else audio_stream(); } // audio_stream() /* ---------------------------------------------------------------------------- * * gpio_initi() * * ---------------------------------------------------------------------------- * * Initialises the GPIO driver for the push buttons and switches. * ---------------------------------------------------------------------------- */ unsigned char gpio_init() { int Status; Status = XGpio_Initialize(&Gpio, BUTTON_SWITCH_ID); if(Status != XST_SUCCESS) return XST_FAILURE; Status = XGpio_Initialize(&Gpio_audio_enable, AUDIO_ENABLE_ID); if(Status != XST_SUCCESS) return XS