1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
|
/*
atmega88_ac_test.c
Copyright 2017 Konstantin Begun
This file is part of simavr.
simavr is free software: 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.
simavr is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY 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 simavr. If not, see <http://www.gnu.org/licenses/>.
*/
#include <avr/io.h>
#include <stdio.h>
#include <avr/interrupt.h>
#include <avr/sleep.h>
#include <util/delay.h>
#include <avr/cpufunc.h>
/*
* This demonstrate how to use the avr_mcu_section.h file
* The macro adds a section to the ELF file with useful
* information for the simulator
*/
#include "avr_mcu_section.h"
AVR_MCU(F_CPU, "atmega88");
static int uart_putchar(char c, FILE *stream) {
if (c == '\n')
uart_putchar('\r', stream);
loop_until_bit_is_set(UCSR0A, UDRE0);
UDR0 = c;
return 0;
}
static FILE mystdout = FDEV_SETUP_STREAM(uart_putchar, NULL,
_FDEV_SETUP_WRITE);
volatile uint8_t int_done;
ISR(ANALOG_COMP_vect)
{
int_done = 1;
}
ISR(TIMER1_CAPT_vect)
{
int_done = 2;
}
static inline void output_value() {
putchar(ACSR & _BV(ACO) ? '1':'0');
}
static inline void output_test(uint8_t expected) {
putchar(int_done == expected ? 'Y':'N');
}
int main(void)
{
stdout = &mystdout;
sei();
ACSR = 0;
printf("Check analog comparator with polling values\n");
// check all the inputs
for(uint8_t t = 0; t < 2; ++t) { // run twice, first with AIN0, second with bandgap
ADCSRB = 0; // multiplexer off
_NOP(); // for sync delay
output_value();
// now with multiplexer
ADCSRB = _BV(ACME);
_NOP();
for(uint8_t i = 0; i < 8;++i)
{
// this is relying that all 3 mux bits are next to each other, which is the case for atmega88
output_value();
ADMUX += _BV(MUX0);
_NOP();
}
// switch to bandgap
ACSR |= _BV(ACBG);
_NOP();
}
putchar('\n');
// check interrupts
printf("Check analog comparator interrupts\n");
// in this test bandgap is expected to be above ADC0 and below ADC1
ADCSRB = _BV(ACME);
ADMUX = 0; // ADC0
ACSR = _BV(ACBG) | _BV(ACIE) | _BV(ACI); // enable interrupts on output triggering
// switch to ADC1
int_done = 0;
ADMUX = _BV(MUX0);
_delay_us(500);
output_test(1);
// back to ADC0
int_done = 0;
ADMUX = 0;
_delay_us(500);
output_test(1);
// change to trigger on falling edge
ACSR = _BV(ACBG) | _BV(ACIE) | _BV(ACI) | _BV(ACIS1);
// switch to ADC1 (falling edge)
int_done = 0;
ADMUX = _BV(MUX0);
_delay_us(500);
output_test(1);
// switch to ADC0 (rising edge)
int_done = 0;
ADMUX = 0;
_delay_us(500);
output_test(0); // expect no interrupt
// change to trigger on rising edge
ACSR = _BV(ACBG) | _BV(ACIE) | _BV(ACI) | _BV(ACIS1) | _BV(ACIS0);
// switch to ADC1 (falling edge)
int_done = 0;
ADMUX = _BV(MUX0);
_delay_us(500);
output_test(0); // expect no interrupt
// switch to ADC0 (rising edge)
int_done = 0;
ADMUX = 0;
_delay_us(500);
output_test(1);
putchar('\n');
// now check timer1 input capture
printf("Check analog comparator triggering timer capture\n");
// setup AC for rising edge, disable comparator own interrupt and enable timer1 capture
ACSR = _BV(ACBG) | _BV(ACIC) | _BV(ACIS1) | _BV(ACIS0);
// now set up timer to capture on rising edge
TCCR1A = 0;
TCNT1 = 5555;
TIMSK1 = _BV(ICIE1); // enable capture interrupt
TCCR1B = _BV(ICES1) | _BV(CS10);
// switch to ADC1 (falling edge)
int_done = 0;
ADMUX = _BV(MUX0);
_delay_us(500);
output_test(0); // expect no interrupt
// switch to ADC0 (rising edge)
int_done = 0;
ADMUX = 0;
_delay_us(500);
output_test(2);
cli();
sleep_cpu();
}
|
