Files
MySensors/AVR/lib/spi/spi-test-adc.c

62 lines
2.0 KiB
C

/*
* Copyright (c) 2009 Andrew Smallbone <andrew@rocketnumbernine.com>
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include <avr/io.h>
#include <util/delay.h>
#include <spi.h>
#define SELECT_ADC PORTB &= ~(1<<PB4)
#define DESELECT_ADC PORTB |= (1<<PB4)
unsigned short read_adc(void)
{
// select ADC wait 100 microseconds then read two bytes
SELECT_ADC;
_delay_us(100);
unsigned char one = send_spi(0xFF);
_delay_us(100);
unsigned char two = send_spi(0xFF);
DESELECT_ADC;
// 12 bits of ADC value is bottom 5 bits of first
// byte and top 7 bits of second, move into 16 bit int
return ((0x1F & one) << 7) | (two >> 1);
}
int main(void)
{
DDRB |= (1<<PB4); // chip select for ADC
// use port D for leds
DDRD = 0xFF;
PORTD = 0x00;
// make sure ADC is unselected and setup spi
SELECT_ADC;
setup_spi(SPI_MODE_0, SPI_MSB, SPI_NO_INTERRUPT, SPI_MSTR_CLK16);
while (1) {
unsigned int num = read_adc();
PORTD = (1<< (num >> 9)); // use the top 3 bytes to turn on LED
_delay_ms(1);
}
}