SPiCboard

7seg.h
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1#ifndef _7SEG_H
2#define _7SEG_H
3
4#include <stdint.h>
5
6#include "check.h"
7
8/**
9 * \addtogroup SEG 7seg (Seven Segment Display)
10 *
11 * \brief Controls the two 7-segment displays on the board
12 *
13 * The two 7-segment displays of the SPiCboard share one common
14 * port of the MCU. The two displays can be connected and
15 * disconnected from the port using two transistors. By quickly
16 * and periodically connecting and disconnecting the displays
17 * an observer will not be able to notice when a display is
18 * disabled and both displays can be used apparently simultaneously.
19 *
20 * The module uses the 8-bit <b>Timer 2</b> of the ATmega328PB
21 * to multiplex the two 7-segment displays.
22 *
23 * \note As the timer is used, interrupts must be enabled for the display to work
24 * (if one of the 7 segments seems to be not working
25 * it is quite likely that interrupts are not enabled --
26 * you have to call <tt>sei()</tt> provided by <tt>avr/interrupt.h</tt>!)
27 *
28 * Example code to display "ok":
29 * \code {.c}
30 * #include <avr/interrupt.h>
31 * #include "7seg.h"
32 *
33 * void main(void){
34 * // enable interrupts
35 * sei();
36 * // display "ok"
37 * sb_7seg_showString("ok");
38 * // spin forever
39 * while(1) {};
40 * }
41 * \endcode
42 *
43 * \sa timer.h
44 *
45 * @{
46 * \file 7seg.h
47 * \version \$Rev: 9414 $
48 */
49
50/**
51 * \brief Prints a number in the range [-9; 99] on the 7-segment display
52 *
53 * \param nmbr the number to print
54 *
55 * \retval 0 success
56 * \retval -1 nmbr is smaller than -9
57 * \retval -2 nmbr is greater than 99
58 */
59int8_t sb_7seg_showNumber(int8_t nmbr);
60
61/**
62 * \brief Prints the hexadecimal representation of an 8-bit unsigned integer on the 7-segment display
63 *
64 * \param nmbr the number to print
65 *
66 * \retval 0 on success
67 * \retval !0 on error
68 */
69int8_t sb_7seg_showHexNumber(uint8_t nmbr);
70
71/**
72 * \brief Prints a 2 character string on the 7-segment display
73 *
74 * Supported characters are in the group [-_ 0-9A-Za-z] (contains space).
75 * Read <a href="http://en.wikipedia.org/wiki/Seven-segment_display_character_representations">this</a>
76 * article for possible representations of these characters. Two
77 * characters of the set should never have the same representation.
78 * No differentiation is made between upper- and lowercase characters.
79 *
80 * \param str the 0-terminated string
81 *
82 * \retval 0 success
83 * \retval -1 character at position 0 not printable
84 * \retval -2 character at position 1 not printable
85 * \retval -3 both characters not printable
86 * \retval -4 str is an empty string
87 */
88int8_t sb_7seg_showString(const char *str);
89
90/**
91 * \brief Set the LEDs of the 7-segment display manually
92 *
93 * The bitfield contains one bit for each of the 7 segment LEDs of a block.
94 * A set bit enables and a cleared bit disables the corresponding LED.
95 * The most significant bit determines the block:
96 * If set, the first block (tens' place) will be used, if cleared the second block (ones' place)
97 * \image html 7seg.png
98 * For example a value of 0x86 (decimal 134, binary representation: 1000 0110) will enlight the LEDs 1 and 2 of the first block.
99 *
100 * \param mask 8-bit bitfield describing the desired 7 segment display state
101 */
102void sb_7seg_setMask(uint8_t mask);
103
104/**
105 * \brief Disables the 7-segment displays
106 *
107 * Any running alarms are unregistered.
108 */
109void sb_7seg_disable(void);
110
111/** @}*/
112
113#endif
114
sb_7seg_showNumber
int8_t sb_7seg_showNumber(int8_t nmbr)
Prints a number in the range [-9; 99] on the 7-segment display.
sb_7seg_showString
int8_t sb_7seg_showString(const char *str)
Prints a 2 character string on the 7-segment display.
sb_7seg_setMask
void sb_7seg_setMask(uint8_t mask)
Set the LEDs of the 7-segment display manually.
sb_7seg_showHexNumber
int8_t sb_7seg_showHexNumber(uint8_t nmbr)
Prints the hexadecimal representation of an 8-bit unsigned integer on the 7-segment display.
sb_7seg_disable
void sb_7seg_disable(void)
Disables the 7-segment displays.