109 lines
2.4 KiB
C
109 lines
2.4 KiB
C
/* Copyright © 2020 tyrolyean
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "avr.h"
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#include "structures.h"
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#include "16550.h"
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#include "dac.h"
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#include "interrupt.h"
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#include <stdio.h>
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#include <string.h>
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#include <stdlib.h>
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#include <avr/wdt.h>
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#include <avr/interrupt.h>
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/* Included early on the prevent the watchdog from killing the already killed
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* microcontroller because of init delay
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*/
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uint8_t mcusr_mirror __attribute__ ((section (".noinit")));
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void get_mcusr(void) \
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__attribute__((naked)) \
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__attribute__((section(".init3")));
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void get_mcusr(void)
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{
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mcusr_mirror = MCUSR;
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MCUSR = 0;
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wdt_disable();
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}
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/* Function used to be more complicated, still remains for readability reasons
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*/
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void set_addr(uint8_t addr){
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ADDR_REG = addr;
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return;
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}
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void reset_modules(){
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/* Setup Data Direction Registers and populate with sane default
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values */
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DATA_DDR_REG = 0xFF; /* Data Bus */
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ADDR_DDR_REG = 0xFF; /* Address Bus */
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CTRL_DDR_REG= 0xFF; /* Control Bus */
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ADDR_REG = 0x00;
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DATA_REG = 0x00;
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CTRL_REG = 0x00;
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/* Cleanly reset the dac uart */
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CTRL_REG |= (1<<WR_SHIFT) | (1<<RD_SHIFT) | (1<<CS_DAC_SHIFT) |
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(1<<MR_SHIFT) | (1<<CS_UART_SHIFT);
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_delay_us(100);
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CTRL_REG &= ~(1<<MR_SHIFT);
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return;
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}
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int routine();
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int main(){
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/* Disable interrupts during initialisation phase */
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cli();
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reset_modules();
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init_uart();
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init_interrupts();
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sei();
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/* Enable the hardware watchdog. In case the microcontroller fails to
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* finish it's task within the specified time, the watchdog will reset
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* the atmel cookie.
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*/
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wdt_enable(WDTO_1S);
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while(1){
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wdt_reset();
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routine();
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}
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return 0;
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}
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int routine(){
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uint8_t received = read_from_uart(UART_REG_LSR);
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if(received & 0x01){
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received = read_from_uart(UART_REG_TXRX);
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write_to_uart(UART_REG_TXRX,received);
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}
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routine_dac();
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return 0;
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}
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