UART Example for DSPIC33 (DSPIC33FJ128GP802)

#include <p33FJ128GP802.h>

_FOSC(OSCIOFNC_ON & FCKSM_CSDCMD & POSCMD_NONE);	//Oscillator Configuration (clock switching: disabled;
							// failsafe clock monitor: disabled; OSC2 pin function: digital IO;
							// primary oscillator mode: disabled)
_FOSCSEL(FNOSC_FRCPLL);					//Oscillator Selection PLL
//_FOSCSEL(FNOSC_FRC);					//Oscillator Selection no PLL
_FWDT(FWDTEN_OFF);					//Turn off WatchDog Timer
_FGS(GCP_OFF);						//Turn off code protect
_FPOR(FPWRT_PWR1);					//Turn off power up timer

void InitUART1() {
	// This is an EXAMPLE, so brutal typing goes into explaining all bit sets

	// The HPC16 board has a DB9 connector wired to UART2, so we will
	// be configuring this port only

	// configure U2MODE
	U1MODEbits.UARTEN = 0;	// Bit15 TX, RX DISABLED, ENABLE at end of func
	//U2MODEbits.notimplemented;	// Bit14
	U1MODEbits.USIDL = 0;	// Bit13 Continue in Idle
	U1MODEbits.IREN = 0;	// Bit12 No IR translation
	U1MODEbits.RTSMD = 0;	// Bit11 Simplex Mode
	//U2MODEbits.notimplemented;	// Bit10
	U1MODEbits.UEN = 0;		// Bits8,9 TX,RX enabled, CTS,RTS not
	U1MODEbits.WAKE = 0;	// Bit7 No Wake up (since we don't sleep here)
	U1MODEbits.LPBACK = 0;	// Bit6 No Loop Back
	U1MODEbits.ABAUD = 0;	// Bit5 No Autobaud (would require sending '55')
	U1MODEbits.URXINV = 0;	// Bit4 IdleState = 1  (for dsPIC)
	U1MODEbits.BRGH = 0;	// Bit3 16 clocks per bit period
	U1MODEbits.PDSEL = 0;	// Bits1,2 8bit, No Parity
	U1MODEbits.STSEL = 0;	// Bit0 One Stop Bit
	
	// Load a value into Baud Rate Generator.  Example is for 9600.
	// See section 19.3.1 of datasheet.
	//  U1BRG = (Fcy / (16 * BaudRate)) - 1
	//  U1BRG = (36850000 / (16 * 9600)) - 1
	//  U1BRG = 238.908854 //Round to 239
	
	U1BRG = 239;

	// Load all values in for U1STA SFR
	U1STAbits.UTXISEL1 = 0;	//Bit15 Int when Char is transferred (1/2 config!)
	U1STAbits.UTXINV = 0;	//Bit14 N/A, IRDA config
	U1STAbits.UTXISEL0 = 0;	//Bit13 Other half of Bit15
	//U2STAbits.notimplemented = 0;	//Bit12
	U1STAbits.UTXBRK = 0;	//Bit11 Disabled
	U1STAbits.UTXEN = 0;	//Bit10 TX pins controlled by periph
	U1STAbits.UTXBF = 0;	//Bit9 *Read Only Bit*
	U1STAbits.TRMT = 0;	//Bit8 *Read Only bit*
	U1STAbits.URXISEL = 0;	//Bits6,7 Int. on character recieved
	U1STAbits.ADDEN = 0;	//Bit5 Address Detect Disabled
	U1STAbits.RIDLE = 0;	//Bit4 *Read Only Bit*
	U1STAbits.PERR = 0;		//Bit3 *Read Only Bit*
	U1STAbits.FERR = 0;		//Bit2 *Read Only Bit*
	U1STAbits.OERR = 0;		//Bit1 *Read Only Bit*
	U1STAbits.URXDA = 0;	//Bit0 *Read Only Bit*


	U1MODEbits.UARTEN = 1;	// And turn the peripheral on

	U1STAbits.UTXEN = 1;
	// I think I have the thing working now.
}

int main() {
	ADPCFG = 0xFFFF;				//make ADC pins all digital	
	
	//PLL setup:
	CLKDIVbits.PLLPRE = 0;          // N1=2: PLL VCO Output Divider Select bits; 0 -> /2 (default)
	PLLFBDbits.PLLDIV = 42 - 2;     // M=40: PLL Feedback Divisor bits; 42 - 2 = 40 -> 40 x multiplier
					// (divisor is 2 more than the value)
	CLKDIVbits.PLLPOST = 0;         // N2=2: PLL Phase Detector Input Divider bits; 0 -> /2
	
	//40 x: 73.700000 MHz = 36.850000 MIPS
	//42 x: 77.385 MHz = 38.6925 MIPS
	//43 x: 79.2275 MHz = 39.61375 MIPS
	
	while(OSCCONbits.LOCK != 1);	// Wait for PLL to lock
	RCONbits.SWDTEN = 0;      // Disable Watch Dog Timer
	
	TRISA = 0b00000000;
	TRISB = 0b00000000;
	
	
	asm volatile ("mov #OSCCONL, w1  \n"
				  "mov #0x46, w2     \n"
				  "mov #0x57, w3     \n"
				  "mov.b w2, [w1]    \n"
				  "mov.b w3, [w1]    \n"
				  "bclr OSCCON, #6");
				  

	RPINR18bits.U1RXR = 7;
	RPOR3bits.RP6R = 0b00011;
	
	asm volatile ("mov #OSCCONL, w1  \n"
				  "mov #0x46, w2     \n"
				  "mov #0x57, w3     \n"
				  "mov.b w2, [w1]    \n"
				  "mov.b w3, [w1]    \n"
				  "bset OSCCON, #6");
	

	InitUART1();
	
	while(1) {

		U1TXREG = 'H';
	}
		
	return 0;
}