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
|
/*
* DHT11/22 to I2C converter
*
* Copyright (c) 2018 Michael Buesch <m@bues.ch>
*
* This program 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 2 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
* 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 this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "main.h"
#include "util.h"
#include "i2c_slave.h"
#include "dht.h"
#include <avr/wdt.h>
#include <avr/sleep.h>
#include <util/crc16.h>
#include <string.h>
#define I2C_ADDR 0x76
static struct host_interface_state {
uint8_t next_data[DHT_DATA_LEN + 2u];
uint8_t tx_data[DHT_DATA_LEN + 2u];
uint8_t tx_index;
} hostintf;
static void host_comm_start(void)
{
/* Copy the message. */
memcpy(hostintf.tx_data, hostintf.next_data, sizeof(hostintf.tx_data));
/* Reset transmit byte index. */
hostintf.tx_index = 0u;
}
static uint8_t host_transmit_callback(bool start)
{
uint8_t data;
if (start)
host_comm_start();
data = hostintf.tx_data[hostintf.tx_index];
if (++hostintf.tx_index >= sizeof(hostintf.tx_data))
hostintf.tx_index = 0u;
return data;
}
static bool host_receive_callback(bool start, uint8_t byte)
{
bool continue_transfer = false;
host_comm_start();
return continue_transfer;
}
static const struct i2c_slave_ops __flash host_interface_slave_ops = {
.transmit = host_transmit_callback,
.receive = host_receive_callback,
};
static void host_interface_init(void)
{
memset(hostintf.next_data, 0u, sizeof(hostintf.next_data));
memset(hostintf.tx_data, 0u, sizeof(hostintf.tx_data));
hostintf.tx_index = 0u;
i2cs_init();
i2cs_add_slave(I2C_ADDR, &host_interface_slave_ops);
}
static void dht_rx_callback(const uint8_t *data)
{
uint8_t i, crc;
/* Increment message sequence counter. */
hostintf.next_data[0]++;
/* Copy the payload data. */
memcpy(hostintf.next_data + 1u, data, DHT_DATA_LEN);
/* Calculate CRC8 */
crc = 0u;
for (i = 0u; i < sizeof(hostintf.next_data) - 1u; i++)
crc = _crc8_ccitt_update(crc, hostintf.next_data[i]);
hostintf.next_data[sizeof(hostintf.next_data) - 1u] = crc;
}
static void basic_port_init(void)
{
PORTB = 0u;
DDRB = (0u << DDB0) | /* Input: ISP-MOSI / I2C-SDA */
(0u << DDB1) | /* Input: ISP-MISO */
(0u << DDB2) | /* Input: ISP-SCK / I2C-SCL */
(1u << DDB3) | /* Output: Debug pin */
(0u << DDB4) | /* Input: DHT signal */
(0u << DDB5); /* Reset */
PORTB = (0u << PB0) | /* Input, no pullup: ISP-MOSI / I2C-SDA */
(1u << PB1) | /* Input, pullup: ISP-MISO */
(0u << PB2) | /* Input, no pullup: ISP-SCK / I2C-SCL */
(0u << PB3) | /* Output, low level: Debug pin */
(1u << PB4) | /* Input, pullup: DHT signal */
(0u << PB5); /* Reset */
}
void early_init(void) __attribute__((naked, section(".init3"), used));
void early_init(void)
{
MCUSR = 0;
wdt_enable(WDTO_500MS);
}
int main(void) _mainfunc;
int main(void)
{
basic_port_init();
dht_init();
host_interface_init();
dht_start(dht_rx_callback);
wdt_enable(WDTO_250MS);
set_sleep_mode(SLEEP_MODE_IDLE);
irq_enable();
while (1) {
sleep_mode();
wdt_reset();
}
}
|
