blob: 02c3fbae1047f14f40bfac8a7e06e01dde91e301 (
plain)
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
|
/* Name: modem.h
* Author: Jari Tulilahti
* Copyright: 2014 Rakettitiede Oy
* License: LGPLv3, see COPYING, and COPYING.LESSER -files for more info
*/
#ifndef MODEM_H_
#define MODEM_H_
#include <avr/interrupt.h>
#include <stdlib.h>
/* Modem ring buffer size must be power of 2 */
#define MODEM_BUFFER_SIZE 32
/* Modem defines */
#define MODEM_SYNC_LEN 42
#define MODEM_TIMER TCNT1L
#define MODEM_PCINT PCINT24
#define MODEM_PCMSK PCMSK3
#define MODEM_PCIE PCIE3
#define MODEM_PIN PA0
#define MODEM_DDR DDRA
/**
* Receive-only modem. Sets up a pin change interrupt on the modem pin
* and receives bytes using a simple protocol. Does not detect or correct
* transmission errors.
*/
class Modem {
private:
uint8_t buffer_head;
uint8_t buffer_tail;
uint8_t buffer[MODEM_BUFFER_SIZE];
bool new_transmission;
void buffer_put(const uint8_t c);
public:
Modem() {new_transmission = false;};
/**
* Checks if a new transmission was started since the last call
* to this function. Returns true if that is the case and false
* otherwise.
* @return true if a new transmission was started
*/
bool newTransmission();
/**
* Checks if there are unprocessed bytes in the modem receive buffer.
* @return number of unprocessed bytes
*/
uint8_t buffer_available(void);
/**
* Get next byte from modem receive buffer.
* @return next unprocessed byte (0 if the buffer is empty)
*/
uint8_t buffer_get(void);
/**
* Enable the modem. Turns on the input voltage divider on MODEM_PIN
* and enables the receive interrupt (MODEM_PCINT).
*/
void enable(void);
/**
* Disable the modem. Disables the receive interrupt and turns off
* the input voltage divider on MODEM_PIN.
*/
void disable(void);
/**
* Called by the pin change interrupt service routine whenever the
* modem pin is toggled. Detects sync pulses, receives bits and
* stores complete bytes in the buffer.
*
* Do not call this function yourself.
*/
void receive(void);
};
#endif /* MODEM_H_ */
|
