1 /*
2 wiring_digital.c - digital input and output functions
3 Part of Arduino - http://www.arduino.cc/
4
5 Copyright (c) 2005-2006 David A. Mellis
6
7 This library is free software; you can redistribute it and/or
8 modify it under the terms of the GNU Lesser General Public
9 License as published by the Free Software Foundation; either
10 version 2.1 of the License, or (at your option) any later version.
11
12 This library is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 Lesser General Public License for more details.
16
17 You should have received a copy of the GNU Lesser General
18 Public License along with this library; if not, write to the
19 Free Software Foundation, Inc., 59 Temple Place, Suite 330,
20 Boston, MA 02111-1307 USA
21
22 Modified 28 September 2010 by Mark Sproul
23
24 $Id: wiring.c 248 2007-02-03 15:36:30Z mellis $
25 */
26
27 #include "wiring_private.h"
28 #include "pins_arduino.h"
29
pinMode(uint8_t pin,uint8_t mode)30 void pinMode(uint8_t pin, uint8_t mode)
31 {
32 uint8_t bit = digitalPinToBitMask(pin);
33 uint8_t port = digitalPinToPort(pin);
34 volatile uint8_t *reg;
35
36 if (port == NOT_A_PIN) return;
37
38 // JWS: can I let the optimizer do this?
39 reg = portModeRegister(port);
40
41 if (mode == INPUT) {
42 uint8_t oldSREG = SREG;
43 cli();
44 *reg &= ~bit;
45 SREG = oldSREG;
46 } else {
47 uint8_t oldSREG = SREG;
48 cli();
49 *reg |= bit;
50 SREG = oldSREG;
51 }
52 }
53
54 // Forcing this inline keeps the callers from having to push their own stuff
55 // on the stack. It is a good performance win and only takes 1 more byte per
56 // user than calling. (It will take more bytes on the 168.)
57 //
58 // But shouldn't this be moved into pinMode? Seems silly to check and do on
59 // each digitalread or write.
60 //
61 // Mark Sproul:
62 // - Removed inline. Save 170 bytes on atmega1280
63 // - changed to a switch statment; added 32 bytes but much easier to read and maintain.
64 // - Added more #ifdefs, now compiles for atmega645
65 //
66 //static inline void turnOffPWM(uint8_t timer) __attribute__ ((always_inline));
67 //static inline void turnOffPWM(uint8_t timer)
turnOffPWM(uint8_t timer)68 static void turnOffPWM(uint8_t timer)
69 {
70 switch (timer)
71 {
72 #if defined(TCCR1A) && defined(COM1A1)
73 case TIMER1A: cbi(TCCR1A, COM1A1); break;
74 #endif
75 #if defined(TCCR1A) && defined(COM1B1)
76 case TIMER1B: cbi(TCCR1A, COM1B1); break;
77 #endif
78
79 #if defined(TCCR2) && defined(COM21)
80 case TIMER2: cbi(TCCR2, COM21); break;
81 #endif
82
83 #if defined(TCCR0A) && defined(COM0A1)
84 case TIMER0A: cbi(TCCR0A, COM0A1); break;
85 #endif
86
87 #if defined(TIMER0B) && defined(COM0B1)
88 case TIMER0B: cbi(TCCR0A, COM0B1); break;
89 #endif
90 #if defined(TCCR2A) && defined(COM2A1)
91 case TIMER2A: cbi(TCCR2A, COM2A1); break;
92 #endif
93 #if defined(TCCR2A) && defined(COM2B1)
94 case TIMER2B: cbi(TCCR2A, COM2B1); break;
95 #endif
96
97 #if defined(TCCR3A) && defined(COM3A1)
98 case TIMER3A: cbi(TCCR3A, COM3A1); break;
99 #endif
100 #if defined(TCCR3A) && defined(COM3B1)
101 case TIMER3B: cbi(TCCR3A, COM3B1); break;
102 #endif
103 #if defined(TCCR3A) && defined(COM3C1)
104 case TIMER3C: cbi(TCCR3A, COM3C1); break;
105 #endif
106
107 #if defined(TCCR4A) && defined(COM4A1)
108 case TIMER4A: cbi(TCCR4A, COM4A1); break;
109 #endif
110 #if defined(TCCR4A) && defined(COM4B1)
111 case TIMER4B: cbi(TCCR4A, COM4B1); break;
112 #endif
113 #if defined(TCCR4A) && defined(COM4C1)
114 case TIMER4C: cbi(TCCR4A, COM4C1); break;
115 #endif
116 #if defined(TCCR5A)
117 case TIMER5A: cbi(TCCR5A, COM5A1); break;
118 case TIMER5B: cbi(TCCR5A, COM5B1); break;
119 case TIMER5C: cbi(TCCR5A, COM5C1); break;
120 #endif
121 }
122 }
123
digitalWrite(uint8_t pin,uint8_t val)124 void digitalWrite(uint8_t pin, uint8_t val)
125 {
126 uint8_t timer = digitalPinToTimer(pin);
127 uint8_t bit = digitalPinToBitMask(pin);
128 uint8_t port = digitalPinToPort(pin);
129 volatile uint8_t *out;
130
131 if (port == NOT_A_PIN) return;
132
133 // If the pin that support PWM output, we need to turn it off
134 // before doing a digital write.
135 if (timer != NOT_ON_TIMER) turnOffPWM(timer);
136
137 out = portOutputRegister(port);
138
139 if (val == LOW) {
140 uint8_t oldSREG = SREG;
141 cli();
142 *out &= ~bit;
143 SREG = oldSREG;
144 } else {
145 uint8_t oldSREG = SREG;
146 cli();
147 *out |= bit;
148 SREG = oldSREG;
149 }
150 }
151
digitalRead(uint8_t pin)152 int digitalRead(uint8_t pin)
153 {
154 uint8_t timer = digitalPinToTimer(pin);
155 uint8_t bit = digitalPinToBitMask(pin);
156 uint8_t port = digitalPinToPort(pin);
157
158 if (port == NOT_A_PIN) return LOW;
159
160 // If the pin that support PWM output, we need to turn it off
161 // before getting a digital reading.
162 if (timer != NOT_ON_TIMER) turnOffPWM(timer);
163
164 if (*portInputRegister(port) & bit) return HIGH;
165 return LOW;
166 }
167