how can i activate UART(rs-232) with register setting at PICC?

Question

I know there is #use rs232 command to activate it, but i want to know how to set registers individually to activate rs232 i'm using PIC18f13k22.

I did like this:

    INTCON = 0xc2;
    IPR1 = 0x7f;
    PIE1 = 0x20;
    PIR1 = 0x10;
    BAUDCON = 0x48;
    RCSTA = 0x90;
    TXSTA = 0xA6;
    SPBRG = 0x82;
    SPBRGH = 0x06;

I looked up PIC18f13k22 datasheet, and found related registers, and set like that. and didn't work. need help! thanks

Answer 1

Here is a complete code that builds with Microchip MPLABX and XC8 v2.30:

/*
 * File:   main.c
 * Author: dan1138
 * Compiler: XC8 v2.30
 *
 * Created on October 6, 2020, 1:41 PM
 */
#pragma config FOSC = IRC, PLLEN = OFF, PCLKEN = ON, FCMEN = OFF, IESO = OFF
#pragma config PWRTEN = OFF, BOREN = SBORDIS, BORV = 19, WDTEN = OFF
#pragma config WDTPS = 32768, HFOFST = ON, MCLRE = ON, STVREN = ON, LVP = OFF
#pragma config BBSIZ = OFF, XINST = OFF, DEBUG = OFF, CP0 = OFF, CP1 = OFF
#pragma config CPB = OFF, CPD = OFF, WRT0 = OFF, WRT1 = OFF, WRTC = OFF
#pragma config WRTB = OFF, WRTD = OFF, EBTR0 = OFF, EBTR1 = OFF, EBTRB = OFF
 
#include <xc.h>
#include <stdio.h>
 
void putch(char txData)
{
    if(1 == RCSTAbits.OERR)
    {
        RCSTAbits.CREN = 0;
        RCSTAbits.CREN = 1;
    }
    while(0 == PIR1bits.TXIF)
    {
    }
    TXREG = txData;
}
 
void main(void)
{
    OSCCON = 0x60;
    OSCCON2 = 0x04;
    OSCTUNE = 0x00;
    LATA = 0x00;
    LATB = 0x00;
    LATC = 0x00;
    TRISA = 0x37;
    TRISB = 0x70;
    TRISC = 0xFF;
    ANSEL = 0xFF;
    ANSELH = 0x07;
    WPUB = 0x00;
    WPUA = 0x00;
    INTCON2bits.nRBPU = 1;
    BAUDCON = 0x08;
    RCSTA = 0x90;
    TXSTA = 0x24;
    SPBRG = 0xCF;
    SPBRGH = 0x00;
    PIR1bits.TXIF = 0;
 
    printf("\r\nPIC18F13K22 UART demo\r\n");
    while (1)
    {
    }
}

The solution to your problem lies in knowing what to set the configuration word values to, and how to comprehend what information can be found in the data sheet.

I know the data sheet is dense and only documents what can be selected, but not why specific values should be chosen.

With more experience you can learn how to read data sheets and what can be useful.

As you made no effort to comment in the code you posted my code is likewise missing anything close to a useful comment.