270 lines
6.5 KiB
C
270 lines
6.5 KiB
C
//
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// basiciotest.c : test code for the io and buffer ops of the UART and SPI ports
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//
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// Copyright (c) 2010 flukso.net
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//
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// This program is free software; you can redistribute it and/or
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// modify it under the terms of the GNU General Public License
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// as published by the Free Software Foundation; either version 2
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// of the License, or (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, write to the Free Software
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// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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//
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// $Id$
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#include <avr/io.h>
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#include <avr/interrupt.h>
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#include <avr/eeprom.h>
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#include <util/delay.h>
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#include "uart.h"
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#include "spi.h"
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#include "ctrl.h"
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#define NO_OP_1 1
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#define NO_OP_2 2
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#define START_TX 4
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#define TRANSMIT 8
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#define HIGH_HEX 16
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#define TO_FROM_UART 32
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#define NEW_CTRL_MSG 64
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#define SPI_END_OF_TX 0x00
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#define SPI_END_OF_MESSAGE '.'
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#define SPI_FORWARD_TO_UART_PORT 'u'
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#define SPI_FORWARD_TO_CTRL_PORT 'l' // 'l'ocal port
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volatile uint8_t spi_status, high_hex;
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// hex to binary/byte decoding
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uint8_t htob(uint16_t hex)
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{
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uint8_t low_hex = (uint8_t) hex;
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uint8_t high_hex = (uint8_t) (hex >> 8);
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uint8_t byte;
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byte = (high_hex > 0x40) ? (high_hex & 0x0F) + 9 : high_hex & 0x0F;
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byte = byte << 4;
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byte |= (low_hex > 0x40) ? (low_hex & 0x0F) + 9 : low_hex & 0x0F;
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return byte;
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}
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// binary/byte to hex encoding
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uint16_t btoh(uint8_t byte)
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{
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uint8_t low_nibble = (byte & 0x0F);
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uint8_t high_nibble = (byte & 0xF0) >> 4;
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uint16_t hex;
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hex = (high_nibble > 0x09) ? high_nibble - 9 + 0x60 : high_nibble + 0x30;
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hex = hex << 8;
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hex |= (low_nibble > 0x09) ? low_nibble - 9 + 0x60 : low_nibble + 0x30;
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return hex;
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}
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ISR(SPI_STC_vect)
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{
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uint8_t spi_rx, rx, tx;
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uint16_t spi_tx;
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// the SPI is double-buffered, requiring two NO_OPs when switching from Tx to Rx
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if (spi_status & (NO_OP_1 | NO_OP_2)) {
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spi_status--;
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return;
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}
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// do we have to transmit the first byte?
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if (spi_status & START_TX) {
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received_from_spi(SPI_FORWARD_TO_CTRL_PORT);
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spi_status &= ~START_TX;
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return;
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}
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// are we in Tx mode?
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if (spi_status & TRANSMIT) {
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if (spi_status & HIGH_HEX) {
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received_from_spi(high_hex);
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spi_status &= ~HIGH_HEX;
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return;
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}
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if (spi_status & TO_FROM_UART) {
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if (!uartReceiveByte(&tx)) {
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received_from_spi(SPI_END_OF_TX);
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spi_status &= ~TRANSMIT;
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spi_status |= NO_OP_2;
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return;
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}
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}
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else {
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if (ctrlGetFromTxBuffer(&tx)) {
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if (tx == SPI_END_OF_MESSAGE) {
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received_from_spi(tx);
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return;
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}
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}
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else {
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received_from_spi(SPI_FORWARD_TO_UART_PORT);
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spi_status |= TO_FROM_UART;
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return;
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}
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}
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spi_tx = btoh(tx);
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high_hex = (uint8_t)spi_tx;
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spi_status |= HIGH_HEX;
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received_from_spi((uint8_t)(spi_tx >> 8));
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return;
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}
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// we're in Rx mode
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switch (spi_rx = received_from_spi(0x00)) {
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case SPI_END_OF_TX:
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spi_status |= TRANSMIT | START_TX;
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spi_status &= ~(HIGH_HEX | TO_FROM_UART);
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break;
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case SPI_END_OF_MESSAGE:
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if (!(spi_status & TO_FROM_UART)) {
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ctrlAddToRxBuffer(spi_rx);
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spi_status |= NEW_CTRL_MSG;
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}
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break;
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case SPI_FORWARD_TO_UART_PORT:
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spi_status |= TO_FROM_UART;
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break;
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case SPI_FORWARD_TO_CTRL_PORT:
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spi_status &= ~TO_FROM_UART;
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break;
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default:
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if (spi_status & HIGH_HEX) {
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rx = htob(((uint16_t)high_hex << 8) + spi_rx);
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if (spi_status & TO_FROM_UART) {
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uartAddToTxBuffer(rx);
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}
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else {
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ctrlAddToRxBuffer(rx);
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}
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}
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else {
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high_hex = spi_rx;
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}
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// toggle the HEX bit in spi_status
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spi_status ^= HIGH_HEX;
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}
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}
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ISR(TIMER1_COMPA_vect)
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{
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/* void */
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}
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ISR(ANALOG_COMP_vect)
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{
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uint8_t i;
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PORTB |= (1<<PB0);
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//disable uC sections to consume less power while writing to EEPROM
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//disable UART Tx and Rx:
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UCSR0B &= ~((1<<RXEN0) | (1<<TXEN0));
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//disable ADC:
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ADCSRA &= ~(1<<ADEN);
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for (i=0; i<128; i++)
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eeprom_write_byte((uint8_t *)i, i);
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//enable UART Tx and Rx:
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UCSR0B |= (1<<RXEN0) | (1<<TXEN0);
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// enable ADC and start a first ADC conversion
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ADCSRA |= (1<<ADEN) | (1<<ADSC);
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PORTB &= ~(1<<PB0);
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}
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void setup_pulse_input(void)
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{
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// PD2=INT0 and PD3=INT1 configuration
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// set as input pin with 20k pull-up enabled
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PORTD |= (1<<PD2) | (1<<PD3);
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// INT0 and INT1 to trigger an interrupt on a falling edge
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EICRA = (1<<ISC01) | (1<<ISC11);
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// enable INT0 and INT1 interrupts
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EIMSK = (1<<INT0) | (1<<INT1);
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}
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void setup_timer1(void)
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{
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// Timer1 clock prescaler set to 1 => fTOV1 = 3686.4kHz / 65536 = 56.25Hz (DS p.134)
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TCCR1B |= (1<<CS10);
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// Increase sampling frequency to 2kHz (= 667Hz per channel) with an error of 0.01% (DS p.122)
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OCR1A = 0x0732;
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// Timer1 set to CTC mode (DS p.133)
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TCCR1B |= 1<<WGM12;
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// Enable output compare match interrupt for timer1 (DS p.136)
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TIMSK1 |= (1<<OCIE1A);
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#if DBG > 0
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// Set PB1=OC1A as output pin
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DDRB |= (1<<DDB1);
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// Toggle pin OC1A=PB1 on compare match
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TCCR1A |= 1<<COM1A0;
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#endif
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}
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void setup_analog_comparator(void)
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{
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// analog comparator setup for brown-out detection
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// PD7=AIN1 configured by default as input to obtain high impedance
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// disable digital input cicuitry on AIN0 and AIN1 pins to reduce leakage current
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DIDR1 |= (1<<AIN1D) | (1<<AIN0D);
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// comparing AIN1 (Vcc/4.4) to bandgap reference (1.1V)
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// bandgap select | AC interrupt enable | AC interrupt on rising edge (DS p.243)
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ACSR |= (1<<ACBG) | (1<<ACIE) | (1<<ACIS1) | (1<<ACIS0);
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}
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int main(void)
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{
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// RS-485: Configure PD5=DE as output pin with low as default
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DDRD |= (1<<DDD5);
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// set high to transmit
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//PORTD |= (1<<PD5);
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setup_timer1();
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setup_pulse_input();
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setup_analog_comparator();
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// initialize the CTRL buffers
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ctrlInit();
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// initialize the UART hardware and buffers
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uartInit();
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// initialize the SPI in slave mode
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setup_spi(SPI_MODE_0, SPI_MSB, SPI_INTERRUPT, SPI_SLAVE);
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for(;;) {
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if (spi_status & NEW_CTRL_MSG) {
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ctrlRxToTxLoop();
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spi_status &= ~NEW_CTRL_MSG;
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}
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// toggle the LED=PB0 pin
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_delay_ms(50);
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DDRB ^= (1<<PB0);
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}
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return 0;
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}
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