dac_max9850.c

nordic 2.4G RF transceiver nRF24z01 firmware source code.

/*= dac_max9850.c ==============================================================
 *
 * Copyright (C) 2005 Nordic Semiconductor
 *
 * This file is distributed in the hope that it will be useful, but WITHOUT
 * WARRANTY OF ANY KIND.
 *
 * Author(s): B鴕ge Strand
 *
 * Description:
 *
 *    DAC specific code for Maxim MAX9850
 *    This file must be ported to any other DAC to be used. 
 *    It must implement all functions in dac.h
 *    All defines specific to MAX9850 reside in this file!
 *
 * Compiler: Tested with WinAVR, avr-gcc (GCC) 3.4.3
 *
 * Revision: 1.0 
 *
 *==============================================================================
 */


#include "dac.h"

// Some forward declarations of functions that are not available externally
char dac_setvolume(void);


// Set up the DAC
char dac_init(void) {
	extern char slaveoutbuf[SLAVEBUFSIZE];			// Global data buffer from MCU to Z1 slave
	extern char volume;
	int n;											// Index to the data buffer
	char temp;
	
	if (volume == 0xFF) volume = 0x11;				// If volume wasn't initiated, set it conveniently
	
	temp = z1_flagready(RXEXEC);					
	if (temp==OKAY) {								// Is TX ready to convey data?
		// Set up a transfer from MCU through ATX and ARX to DAC
		slaveoutbuf[n=0] = 0x02;					// Data for RXDCMD, 2-wire at RX, 2-wire start/stop, 100kb/s
		slaveoutbuf[++n] = 10;						// Data for RXWCNT, sending 10 bytes to DAC
		slaveoutbuf[++n] = 0;						// Data for RXRCNT, reading 0 bytes from DAC
		z1_multiwrite(RXDCMD, RXRCNT);				// Send configuration data
		
		slaveoutbuf[n=0] = 0x20;					// Data for RXBUF_0, 2-w hardware adr. of MAX9850 
		slaveoutbuf[++n] = 0x02;					// Data for RXBUF_1, internal address of setup register
		slaveoutbuf[++n] = volume;					// Data for RXBUF_2, MAX9850 address 0x02, "Volume"
		slaveoutbuf[++n] = 0x00;					// Data for RXBUF_3, MAX9850 address 0x03, "General Purpose"
		slaveoutbuf[++n] = 0x00;					// Data for RXBUF_4, MAX9850 address 0x04, "Interrupt Enable"
		slaveoutbuf[++n] = 0xfd;					// Data for RXBUF_5, MAX9850 address 0x05, "Enable"
		slaveoutbuf[++n] = 0x00;					// Data for RXBUF_6, MAX9850 address 0x06, "Clock"
		slaveoutbuf[++n] = 0x00;					// Data for RXBUF_7, MAX9850 address 0x07, "Charge Pump"
		slaveoutbuf[++n] = 0x80;					// Data for RXBUF_8, MAX9850 address 0x08, "LRCK MSB"
		slaveoutbuf[++n] = 0x10;					// Data for RXBUF_9, MAX9850 address 0x09, "LRCK LSB"
		z1_multiwrite(RXBUF_0, RXBUF_9);			// Move data through to DAC
		z1_setflag(RXEXEC);							// Execute transfer to RX 
	}
	return temp;									// Return whatever z1_flagready() said
}


// Increase volume
char dac_volume_up(void) {
	extern char volume;							// Global variable 
	
	if (volume > 0)									// On MAX9850, 0x00 is highest volume, 0x27 is lowest
		volume--;		
	return (dac_setvolume());						// Write the new volume setting to DAC
}
	

// Decrease volume
char dac_volume_down(void) {
	extern char volume;							// Global variable
	
	if (volume < 0x27)								// On MAX9850, 0x00 is highest volume, 0x27 is lowest
		volume++;		
	return (dac_setvolume());						// Write the new volume setting to DAC
}
	

// Transmit volume information
char dac_setvolume(void) {
	extern char slaveoutbuf[SLAVEBUFSIZE];			// Global data buffer from MCU to Z1 slave
	extern char volume;
	int n;											// Index to the data buffer
	char temp;
	
	temp = z1_flagready(RXEXEC);					// Is Z1 ready to push data to DAC?	
		
	if (temp==OKAY) {								// Is TX ready to convey data?
		// Set up a transfer from MCU through ATX and ARX to DAC
		slaveoutbuf[n=0] = 0x02;					// Data for RXDCMD, 2-wire at RX, 2-wire start/stop, 100kb/s
		slaveoutbuf[++n] = 0x03;					// Data for RXWCNT, sending 3 bytes to DAC
		slaveoutbuf[++n] = 0x00;					// Data for RXRCNT, reading 0 bytes from DAC
		z1_multiwrite(RXDCMD, RXRCNT);				// Send configuration data
		
		slaveoutbuf[n=0] = 0x20;					// Data for RXBUF_0, 2-w hardware adr. of MAX9850 FIX: define?
		slaveoutbuf[++n] = 0x02;					// Data for RXBUF_1, internal address of setup register
		slaveoutbuf[++n] = volume;					// Data for RXBUF_2, MAX9850 address 0x02, "Volume"
		z1_multiwrite(RXBUF_0, RXBUF_2);			// Move data through to DAC
		z1_setflag(RXEXEC);							// Execute transfer to RX 
	}
	return temp;									// Return whatever z1_flagready() said
}