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#include <p24Fxxxx.h>
#include <xc.h>
#include <stdlib.h>
// PIC24FJ64GA002 Configuration Bit Settings
// CW1: FLASH CONFIGURATION WORD 1 (see PIC24 Family Reference Manual 24.1)
#pragma config ICS = PGx1 // Comm Channel Select (Emulator EMUC1/EMUD1 pins are shared with PGC1/PGD1)
#pragma config FWDTEN = OFF // Watchdog Timer Enable (Watchdog Timer is disabled)
#pragma config GWRP = OFF // General Code Segment Write Protect (Writes to program memory are allowed)
#pragma config GCP = OFF // General Code Segment Code Protect (Code protection is disabled)
#pragma config JTAGEN = OFF // JTAG Port Enable (JTAG port is disabled)
// CW2: FLASH CONFIGURATION WORD 2 (see PIC24 Family Reference Manual 24.1)
#pragma config POSCMOD = NONE // Primary Oscillator Select (Primary oscillator disabled.
// Primary Oscillator refers to an external osc connected to the OSC1 and OSC2 pins)
#pragma config I2C1SEL = PRI // I2C1 Pin Location Select (Use default SCL1/SDA1 pins)
#pragma config IOL1WAY = OFF // IOLOCK Protection (IOLOCK may be changed via unlocking seq)
#pragma config OSCIOFNC = ON // OSC2/CLKO/RC15 functions as port I/O (RC15)
#pragma config FCKSM = CSECME // Clock Switching and Monitor (Clock switching is enabled,
// Fail-Safe Clock Monitor is enabled)
#pragma config FNOSC = FRCPLL // Oscillator Select (Fast RC Oscillator with PLL module (FRCPLL))
volatile unsigned char buffer[64];
volatile unsigned char front = 0;
volatile unsigned char back = 0;
void __attribute__((__interrupt__,__auto_psv__)) _U1RXInterrupt(void)
{
IFS0bits.U1RXIF = 0;
buffer[front++] = U1RXREG;
front &= 63;
}
void PPutch(const unsigned char c)
{
while (!IFS0bits.U1TXIF) ;
IFS0bits.U1TXIF = 0;
U1TXREG = ((c+3-65) %26) + 65;
}
unsigned char PGetch(void)
{
unsigned char x;
while (front == back) ;
x = buffer[back++];
back &= 63;
return x;
}
void setup(void)
{
CLKDIVbits.RCDIV = 0;
AD1PCFG = 0x9fff; // For digital I/O.
// I think the following two lines are irrelevant. The UART doc
// Page 3, when describing the UARTEN bit in UxMODE says that when UARTEN
// is set, TRISx are ignored and instead UEN and UTXEN control pins.
_TRISB6 = 0; // U1TX output
_TRISB10 = 1; // U1RX input
U1MODE = 0; // UEN<1:0> bits control the pins
// U1BRG = 34; // 115200 baud,
// U1MODEbits.BRGH = 1;
U1MODEbits.BRGH = 0;
U1BRG = 25; // 38400 baud (check the calculation with the datasheet)
U1MODEbits.UEN = 0;
U1MODEbits.UARTEN = 1;
U1STAbits.UTXEN = 1;
// Peripheral Pin Select
__builtin_write_OSCCONL(OSCCON & 0xbf); // unlock PPS
_RP6R = 0x0003; //RB6->UART1:U1TX; See Table 10-3 on P109 of the datasheet
_U1RXR = 10; //RB10->UART1:U1RX;
__builtin_write_OSCCONL(OSCCON | 0x40); // lock PPS
IFS0bits.U1RXIF = 0;
IEC0bits.U1RXIE = 1;
}
int main(int argc, char *argv[])
{
setup();
int i;
// waste some time
for (i = 0; i < 30000; i++) i = i;
// transmit data on UART
// for (i = ' '; i < 0x7f; i++)
// PPutch(i);
PPutch(0x0D); // new line characters
PPutch(0x0A);
while (1)
{
unsigned int x;
x = PGetch();
if (x>='a' && x<='z')
x += 'A' - 'a';
PPutch(x);
}
return 0; // never reached (we hope)
}
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