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////////////////////////////////////////////////////////////////////////////////

//

// Filename:    uartecho.c

//

// Project:     CMod S6 System on a Chip, ZipCPU demonstration project

//

// Purpose:     To simply test if both parts of the UART work.  All this file

//              does is attempt to receive a character from the UART, and if

//      successful, print it back out the UART.

//

// Creator:     Dan Gisselquist, Ph.D.

//              Gisselquist Technology, LLC

//

////////////////////////////////////////////////////////////////////////////////

//

// Copyright (C) 2015-2017, Gisselquist Technology, LLC

//

// This program is free software (firmware): you can redistribute it and/or

// modify it under the terms of  the GNU General Public License as published

// by the Free Software Foundation, either version 3 of the License, or (at

// your option) any later version.

//

// This program is distributed in the hope that it will be useful, but WITHOUT

// ANY WARRANTY; without even the implied warranty of MERCHANTIBILITY or

// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

// for more details.

//

// You should have received a copy of the GNU General Public License along

// with this program.  (It's in the $(ROOT)/doc directory.  Run make with no

// target there if the PDF file isn't present.)  If not, see

// <http://www.gnu.org/licenses/> for a copy.

//

// License:     GPL, v3, as defined and found on www.gnu.org,

//              http://www.gnu.org/licenses/gpl.html

//

//

////////////////////////////////////////////////////////////////////////////////

//

//

#include "board.h"

void    entry(void) {

        SYSPIC = INT_CLEARPIC;

        while(1) {

                int     ch;

                SYSPIC = INT_UARTRX;

                while((SYSPIC & INT_UARTRX)==0)

                        ;

                ch = _uart & 0x0ff;

                SYSPIC = INT_UARTTX;

                while((SYSPIC & INT_UARTTX)==0)

                        ;

                _uart = ch;

        }

}