3 * Arduino compatable (ish) Wiring library for the Raspberry Pi
4 * Copyright (c) 2012 Gordon Henderson
5 * Additional code for pwmSetClock by Chris Hall <chris@kchall.plus.com>
7 * Thanks to code samples from Gert Jan van Loo and the
8 * BCM2835 ARM Peripherals manual, however it's missing
9 * the clock section /grr/mutter/
10 ***********************************************************************
11 * This file is part of wiringPi:
12 * https://projects.drogon.net/raspberry-pi/wiringpi/
14 * wiringPi is free software: you can redistribute it and/or modify
15 * it under the terms of the GNU Lesser General Public License as
16 * published by the Free Software Foundation, either version 3 of the
17 * License, or (at your option) any later version.
19 * wiringPi is distributed in the hope that it will be useful,
20 * but WITHOUT ANY WARRANTY; without even the implied warranty of
21 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22 * GNU Lesser General Public License for more details.
24 * You should have received a copy of the GNU Lesser General Public
25 * License along with wiringPi.
26 * If not, see <http://www.gnu.org/licenses/>.
27 ***********************************************************************
33 // Added an abstraction layer to the main routines to save a tiny
34 // bit of run-time and make the clode a little cleaner (if a little
36 // Added waitForInterrupt code
40 // Added in support to use the /sys/class/gpio interface.
42 // Fixed a few more bugs to do with range-checking when in GPIO mode.
45 // Added c++ support for the .h file
46 // Added a new function to allow for using my "pin" numbers, or native
48 // Removed my busy-loop delay and replaced it with a call to delayMicroseconds
51 // Added in the 2 UART pins
52 // Change maxPins to numPins to more accurately reflect purpose
54 // Pad drive current fiddling
70 #include <sys/types.h>
77 void (*pinMode) (int pin, int mode) ;
78 void (*pullUpDnControl) (int pin, int pud) ;
79 void (*digitalWrite) (int pin, int value) ;
80 void (*pwmWrite) (int pin, int value) ;
81 void (*setPadDrive) (int group, int value) ;
82 int (*digitalRead) (int pin) ;
83 int (*waitForInterrupt) (int pin, int mS) ;
84 void (*delayMicroseconds) (unsigned int howLong) ;
85 void (*pwmSetMode) (int mode) ;
86 void (*pwmSetRange) (unsigned int range) ;
87 void (*pwmSetClock) (int divisor) ;
97 #define BCM_PASSWORD 0x5A000000
100 // Port function select bits
102 #define FSEL_INPT 0b000
103 #define FSEL_OUTP 0b001
104 #define FSEL_ALT0 0b100
105 #define FSEL_ALT0 0b100
106 #define FSEL_ALT1 0b101
107 #define FSEL_ALT2 0b110
108 #define FSEL_ALT3 0b111
109 #define FSEL_ALT4 0b011
110 #define FSEL_ALT5 0b010
112 // Access from ARM Running Linux
113 // Take from Gert/Doms code. Some of this is not in the manual
114 // that I can find )-:
116 #define BCM2708_PERI_BASE 0x20000000
117 #define GPIO_PADS (BCM2708_PERI_BASE + 0x100000)
118 #define CLOCK_BASE (BCM2708_PERI_BASE + 0x101000)
119 #define GPIO_BASE (BCM2708_PERI_BASE + 0x200000)
120 #define GPIO_TIMER (BCM2708_PERI_BASE + 0x00B000)
121 #define GPIO_PWM (BCM2708_PERI_BASE + 0x20C000)
123 #define PAGE_SIZE (4*1024)
124 #define BLOCK_SIZE (4*1024)
128 #define PWM_CONTROL 0
135 #define PWMCLK_CNTL 40
136 #define PWMCLK_DIV 41
138 #define PWM1_MS_MODE 0x8000 // Run in MS mode
139 #define PWM1_USEFIFO 0x2000 // Data from FIFO
140 #define PWM1_REVPOLAR 0x1000 // Reverse polarity
141 #define PWM1_OFFSTATE 0x0800 // Ouput Off state
142 #define PWM1_REPEATFF 0x0400 // Repeat last value if FIFO empty
143 #define PWM1_SERIAL 0x0200 // Run in serial mode
144 #define PWM1_ENABLE 0x0100 // Channel Enable
146 #define PWM0_MS_MODE 0x0080 // Run in MS mode
147 #define PWM0_USEFIFO 0x0020 // Data from FIFO
148 #define PWM0_REVPOLAR 0x0010 // Reverse polarity
149 #define PWM0_OFFSTATE 0x0008 // Ouput Off state
150 #define PWM0_REPEATFF 0x0004 // Repeat last value if FIFO empty
151 #define PWM0_SERIAL 0x0002 // Run in serial mode
152 #define PWM0_ENABLE 0x0001 // Channel Enable
156 #define TIMER_LOAD (0x400 >> 2)
157 #define TIMER_VALUE (0x404 >> 2)
158 #define TIMER_CONTROL (0x408 >> 2)
159 #define TIMER_IRQ_CLR (0x40C >> 2)
160 #define TIMER_IRQ_RAW (0x410 >> 2)
161 #define TIMER_IRQ_MASK (0x414 >> 2)
162 #define TIMER_RELOAD (0x418 >> 2)
163 #define TIMER_PRE_DIV (0x41C >> 2)
164 #define TIMER_COUNTER (0x420 >> 2)
166 // Locals to hold pointers to the hardware
168 static volatile uint32_t *gpio ;
169 static volatile uint32_t *pwm ;
170 static volatile uint32_t *clk ;
171 static volatile uint32_t *pads ;
172 static volatile uint32_t *timer ;
173 static volatile uint32_t *timerIrqRaw ;
177 static int wiringPiDebug = FALSE ;
179 // The BCM2835 has 54 GPIO pins.
180 // BCM2835 data sheet, Page 90 onwards.
181 // There are 6 control registers, each control the functions of a block
183 // Each control register has 10 sets of 3 bits per GPIO pin:
185 // 000 = GPIO Pin X is an input
186 // 001 = GPIO Pin X is an output
187 // 100 = GPIO Pin X takes alternate function 0
188 // 101 = GPIO Pin X takes alternate function 1
189 // 110 = GPIO Pin X takes alternate function 2
190 // 111 = GPIO Pin X takes alternate function 3
191 // 011 = GPIO Pin X takes alternate function 4
192 // 010 = GPIO Pin X takes alternate function 5
194 // So the 3 bits for port X are:
195 // X / 10 + ((X % 10) * 3)
198 // Map a file descriptor from the /sys/class/gpio/gpioX/value
200 static int sysFds [64] ;
202 // Doing it the Arduino way with lookup tables...
203 // Yes, it's probably more innefficient than all the bit-twidling, but it
204 // does tend to make it all a bit clearer. At least to me!
207 // Take a Wiring pin (0 through X) and re-map it to the BCM_GPIO pin
208 // Cope for 2 different board revieions here
210 static int *pinToGpio ;
212 static int pinToGpioR1 [64] =
214 17, 18, 21, 22, 23, 24, 25, 4, // From the Original Wiki - GPIO 0 through 7
215 0, 1, // I2C - SDA0, SCL0
216 8, 7, // SPI - CE1, CE0
217 10, 9, 11, // SPI - MOSI, MISO, SCLK
218 14, 15, // UART - Tx, Rx
222 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, // ... 31
223 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, // ... 47
224 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, // ... 63
227 static int pinToGpioR2 [64] =
229 17, 18, 27, 22, 23, 24, 25, 4, // From the Original Wiki - GPIO 0 through 7: wpi 0 - 7
230 2, 3, // I2C - SDA0, SCL0 wpi 8 - 9
231 8, 7, // SPI - CE1, CE0 wpi 10 - 11
232 10, 9, 11, // SPI - MOSI, MISO, SCLK wpi 12 - 14
233 14, 15, // UART - Tx, Rx wpi 15 - 16
234 28, 29, 30, 31, // New GPIOs 8 though 11 wpi 17 - 20
238 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, // ... 31
239 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, // ... 47
240 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, // ... 63
245 // Map a BCM_GPIO pin to it's control port. (GPFSEL 0-5)
247 static uint8_t gpioToGPFSEL [] =
249 0,0,0,0,0,0,0,0,0,0,
250 1,1,1,1,1,1,1,1,1,1,
251 2,2,2,2,2,2,2,2,2,2,
252 3,3,3,3,3,3,3,3,3,3,
253 4,4,4,4,4,4,4,4,4,4,
254 5,5,5,5,5,5,5,5,5,5,
259 // Define the shift up for the 3 bits per pin in each GPFSEL port
261 static uint8_t gpioToShift [] =
263 0,3,6,9,12,15,18,21,24,27,
264 0,3,6,9,12,15,18,21,24,27,
265 0,3,6,9,12,15,18,21,24,27,
266 0,3,6,9,12,15,18,21,24,27,
267 0,3,6,9,12,15,18,21,24,27,
272 // (Word) offset to the GPIO Set registers for each GPIO pin
274 static uint8_t gpioToGPSET [] =
276 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
277 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
282 // (Word) offset to the GPIO Clear registers for each GPIO pin
284 static uint8_t gpioToGPCLR [] =
286 10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,
287 11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,
292 // (Word) offset to the GPIO Input level registers for each GPIO pin
294 static uint8_t gpioToGPLEV [] =
296 13,13,13,13,13,13,13,13,13,13,13,13,13,13,13,13,13,13,13,13,13,13,13,13,13,13,13,13,13,13,13,13,
297 14,14,14,14,14,14,14,14,14,14,14,14,14,14,14,14,14,14,14,14,14,14,14,14,14,14,14,14,14,14,14,14,
303 // (Word) offset to the Event Detect Status
305 static uint8_t gpioToEDS [] =
307 16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,
308 17,17,17,17,17,17,17,17,17,17,17,17,17,17,17,17,17,17,17,17,17,17,17,17,17,17,17,17,17,17,17,17,
312 // (Word) offset to the Rising edgde ENable register
314 static uint8_t gpioToREN [] =
316 19,19,19,19,19,19,19,19,19,19,19,19,19,19,19,19,19,19,19,19,19,19,19,19,19,19,19,19,19,19,19,19,
317 20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,
321 // (Word) offset to the Falling edgde ENable register
323 static uint8_t gpioToFEN [] =
325 22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,
326 23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,
332 // (Word) offset to the Pull Up Down Clock regsiter
336 static uint8_t gpioToPUDCLK [] =
338 38,38,38,38,38,38,38,38,38,38,38,38,38,38,38,38,38,38,38,38,38,38,38,38,38,38,38,38,38,38,38,38,
339 39,39,39,39,39,39,39,39,39,39,39,39,39,39,39,39,39,39,39,39,39,39,39,39,39,39,39,39,39,39,39,39,
344 // the ALT value to put a GPIO pin into PWM mode
346 static uint8_t gpioToPwmALT [] =
348 0, 0, 0, 0, 0, 0, 0, 0, // 0 -> 7
349 0, 0, 0, 0, FSEL_ALT0, FSEL_ALT0, 0, 0, // 8 -> 15
350 0, 0, FSEL_ALT5, FSEL_ALT5, 0, 0, 0, 0, // 16 -> 23
351 0, 0, 0, 0, 0, 0, 0, 0, // 24 -> 31
352 0, 0, 0, 0, 0, 0, 0, 0, // 32 -> 39
353 FSEL_ALT0, FSEL_ALT0, 0, 0, 0, FSEL_ALT0, 0, 0, // 40 -> 47
354 0, 0, 0, 0, 0, 0, 0, 0, // 48 -> 55
355 0, 0, 0, 0, 0, 0, 0, 0, // 56 -> 63
358 static uint8_t gpioToPwmPort [] =
360 0, 0, 0, 0, 0, 0, 0, 0, // 0 -> 7
361 0, 0, 0, 0, PWM0_DATA, PWM1_DATA, 0, 0, // 8 -> 15
362 0, 0, PWM0_DATA, PWM1_DATA, 0, 0, 0, 0, // 16 -> 23
363 0, 0, 0, 0, 0, 0, 0, 0, // 24 -> 31
364 0, 0, 0, 0, 0, 0, 0, 0, // 32 -> 39
365 PWM0_DATA, PWM1_DATA, 0, 0, 0, PWM1_DATA, 0, 0, // 40 -> 47
366 0, 0, 0, 0, 0, 0, 0, 0, // 48 -> 55
367 0, 0, 0, 0, 0, 0, 0, 0, // 56 -> 63
372 // Time for easy calculations
374 static unsigned long long epoch ;
378 *********************************************************************************
384 * Translate a wiringPi Pin number to native GPIO pin number.
385 * (We don't use this here, prefering to just do the lookup directly,
386 * but it's been requested!)
387 *********************************************************************************
390 int wpiPinToGpio (int wpiPin)
392 return pinToGpio [wpiPin & 63] ;
398 * Return a number representing the hardware revision of the board.
399 * Revision is currently 1 or 2. -1 is returned on error.
400 *********************************************************************************
403 int piBoardRev (void)
409 static int boardRev = -1 ;
411 // No point checking twice...
416 if ((cpuFd = fopen ("/proc/cpuinfo", "r")) == NULL)
419 while (fgets (line, 80, cpuFd) != NULL)
420 if (strncmp (line, "Revision", 8) == 0)
421 for (c = line ; *c ; ++c)
432 fprintf (stderr, "piBoardRev: Unable to determine board revision from /proc/cpuinfo\n") ;
437 // If you have overvolted the Pi, then it appears that the revision
438 // has 100000 added to it!
442 printf ("piboardRev: This Pi has/is overvolted!\n") ;
446 /**/ if ((r == 2) || (r == 3))
448 else if ((r == 4) || (r == 5) || (r == 6))
452 fprintf (stderr, "piBoardRev: Unable to determine board revision from %d\n", r) ;
458 printf ("piboardRev: Revision: %d, board revision: %d\n", r, boardRev) ;
467 * Sets the mode of a pin to be input, output or PWM output
468 *********************************************************************************
471 void pinModeGpio (int pin, int mode)
473 int fSel, shift, alt ;
477 fSel = gpioToGPFSEL [pin] ;
478 shift = gpioToShift [pin] ;
480 /**/ if (mode == INPUT)
481 *(gpio + fSel) = (*(gpio + fSel) & ~(7 << shift)) ; // Sets bits to zero = input
482 else if (mode == OUTPUT)
483 *(gpio + fSel) = (*(gpio + fSel) & ~(7 << shift)) | (1 << shift) ;
484 else if (mode == PWM_OUTPUT)
486 if ((alt = gpioToPwmALT [pin]) == 0) // Not a PWM pin
489 // Set pin to PWM mode
491 *(gpio + fSel) = (*(gpio + fSel) & ~(7 << shift)) | (alt << shift) ;
493 // Page 107 of the BCM Peripherals manual talks about the GPIO clocks,
494 // but I'm assuming (hoping!) that this applies to other clocks too.
496 *(pwm + PWM_CONTROL) = 0 ; // Stop PWM
497 *(clk + PWMCLK_CNTL) = BCM_PASSWORD | 0x01 ; // Stop PWM Clock
498 delayMicroseconds (110) ; // See comments in pwmSetClockWPi
500 (void)*(pwm + PWM_CONTROL) ;
501 while ((*(pwm + PWM_CONTROL) & 0x80) != 0) // Wait for clock to be !BUSY
502 delayMicroseconds (1) ;
504 *(clk + PWMCLK_DIV) = BCM_PASSWORD | (32 << 12) ; // set pwm div to 32 (19.2/32 = 600KHz)
505 *(clk + PWMCLK_CNTL) = BCM_PASSWORD | 0x11 ; // enable clk
507 // Default range regsiter of 1024
509 *(pwm + PWM0_DATA) = 0 ; *(pwm + PWM0_RANGE) = 1024 ;
510 *(pwm + PWM1_DATA) = 0 ; *(pwm + PWM1_RANGE) = 1024 ;
512 // Enable PWMs in balanced mode (default)
514 *(pwm + PWM_CONTROL) = PWM0_ENABLE | PWM1_ENABLE ;
517 // When we change mode of any pin, we remove the pull up/downs
518 // Or we used to... Hm. Commented out now because for some wieird reason,
519 // it seems to block subsequent attempts to set the pull up/downs and I've
520 // not quite gotten to the bottom of why this happens
521 // The down-side is that the pull up/downs are rememberd in the SoC between
522 // power cycles, so it's going to be a good idea to explicitly set them in
525 // pullUpDnControl (pin, PUD_OFF) ;
529 void pinModeWPi (int pin, int mode)
531 pinModeGpio (pinToGpio [pin & 63], mode) ;
534 void pinModeSys (int pin, int mode)
542 * Allow the user to control some of the PWM functions
543 *********************************************************************************
546 void pwmSetModeWPi (int mode)
548 if (mode == PWM_MODE_MS)
549 *(pwm + PWM_CONTROL) = PWM0_ENABLE | PWM1_ENABLE | PWM0_MS_MODE | PWM1_MS_MODE ;
551 *(pwm + PWM_CONTROL) = PWM0_ENABLE | PWM1_ENABLE ;
554 void pwmSetModeSys (int mode)
560 void pwmSetRangeWPi (unsigned int range)
562 *(pwm + PWM0_RANGE) = range ; delayMicroseconds (10) ;
563 *(pwm + PWM1_RANGE) = range ; delayMicroseconds (10) ;
566 void pwmSetRangeSys (unsigned int range)
573 * Set/Change the PWM clock. Originally my code, but changed
574 * (for the better!) by Chris Hall, <chris@kchall.plus.com>
575 * after further study of the manual and testing with a 'scope
576 *********************************************************************************
579 void pwmSetClockWPi (int divisor)
581 unsigned int pwm_control ;
585 printf ("Setting to: %d. Current: 0x%08X\n", divisor, *(clk + PWMCLK_DIV)) ;
587 pwm_control = *(pwm + PWM_CONTROL) ; // preserve PWM_CONTROL
589 // We need to stop PWM prior to stopping PWM clock in MS mode otherwise BUSY
592 *(pwm + PWM_CONTROL) = 0 ; // Stop PWM
594 // Stop PWM clock before changing divisor. The delay after this does need to
595 // this big (95uS occasionally fails, 100uS OK), it's almost as though the BUSY
596 // flag is not working properly in balanced mode. Without the delay when DIV is
597 // adjusted the clock sometimes switches to very slow, once slow further DIV
598 // adjustments do nothing and it's difficult to get out of this mode.
600 *(clk + PWMCLK_CNTL) = BCM_PASSWORD | 0x01 ; // Stop PWM Clock
601 delayMicroseconds (110) ; // prevents clock going sloooow
603 while ((*(pwm + PWM_CONTROL) & 0x80) != 0) // Wait for clock to be !BUSY
604 delayMicroseconds (1) ;
606 *(clk + PWMCLK_DIV) = BCM_PASSWORD | (divisor << 12) ;
608 *(clk + PWMCLK_CNTL) = BCM_PASSWORD | 0x11 ; // Start PWM clock
609 *(pwm + PWM_CONTROL) = pwm_control ; // restore PWM_CONTROL
612 printf ("Set to: %d. Now : 0x%08X\n", divisor, *(clk + PWMCLK_DIV)) ;
615 void pwmSetClockSys (int divisor)
625 * Enables edge-detect mode on a pin - from a 0 to a 1 or 1 to 0
626 * Pin must already be in input mode with appropriate pull up/downs set.
627 *********************************************************************************
630 void pinEnableED01Pi (int pin)
632 pin = pinToGpio [pin & 63] ;
641 *********************************************************************************
644 void digitalWriteWPi (int pin, int value)
646 pin = pinToGpio [pin & 63] ;
649 *(gpio + gpioToGPCLR [pin]) = 1 << (pin & 31) ;
651 *(gpio + gpioToGPSET [pin]) = 1 << (pin & 31) ;
654 void digitalWriteGpio (int pin, int value)
659 *(gpio + gpioToGPCLR [pin]) = 1 << (pin & 31) ;
661 *(gpio + gpioToGPSET [pin]) = 1 << (pin & 31) ;
664 void digitalWriteSys (int pin, int value)
668 if (sysFds [pin] != -1)
671 write (sysFds [pin], "0\n", 2) ;
673 write (sysFds [pin], "1\n", 2) ;
680 * Set an output PWM value
681 *********************************************************************************
684 void pwmWriteGpio (int pin, int value)
689 port = gpioToPwmPort [pin] ;
691 *(pwm + port) = value ;
694 void pwmWriteWPi (int pin, int value)
696 pwmWriteGpio (pinToGpio [pin & 63], value) ;
699 void pwmWriteSys (int pin, int value)
707 * Set the PAD driver value
708 *********************************************************************************
711 void setPadDriveWPi (int group, int value)
715 if ((group < 0) || (group > 2))
718 wrVal = BCM_PASSWORD | 0x18 | (value & 7) ;
719 *(pads + group + 11) = wrVal ;
722 printf ("setPadDrive: Group: %d, value: %d (%08X)\n", group, value, wrVal) ;
723 printf ("Read : %08X\n", *(pads + group + 11)) ;
727 void setPadDriveGpio (int group, int value)
729 setPadDriveWPi (group, value) ;
732 void setPadDriveSys (int group, int value)
740 * Read the value of a given Pin, returning HIGH or LOW
741 *********************************************************************************
744 int digitalReadWPi (int pin)
746 pin = pinToGpio [pin & 63] ;
748 if ((*(gpio + gpioToGPLEV [pin]) & (1 << (pin & 31))) != 0)
754 int digitalReadGpio (int pin)
758 if ((*(gpio + gpioToGPLEV [pin]) & (1 << (pin & 31))) != 0)
764 int digitalReadSys (int pin)
770 if (sysFds [pin] == -1)
773 lseek (sysFds [pin], 0L, SEEK_SET) ;
774 read (sysFds [pin], &c, 1) ;
775 return (c == '0') ? 0 : 1 ;
781 * Control the internal pull-up/down resistors on a GPIO pin
782 * The Arduino only has pull-ups and these are enabled by writing 1
783 * to a port when in input mode - this paradigm doesn't quite apply
785 *********************************************************************************
788 void pullUpDnControlGpio (int pin, int pud)
793 *(gpio + GPPUD) = pud ; delayMicroseconds (5) ;
794 *(gpio + gpioToPUDCLK [pin]) = 1 << (pin & 31) ; delayMicroseconds (5) ;
796 *(gpio + GPPUD) = 0 ; delayMicroseconds (5) ;
797 *(gpio + gpioToPUDCLK [pin]) = 0 ; delayMicroseconds (5) ;
800 void pullUpDnControlWPi (int pin, int pud)
802 pullUpDnControlGpio (pinToGpio [pin & 63], pud) ;
805 void pullUpDnControlSys (int pin, int pud)
813 * Wait for Interrupt on a GPIO pin.
814 * This is actually done via the /sys/class/gpio interface regardless of
815 * the wiringPi access mode in-use. Maybe sometime it might get a better
816 * way for a bit more efficiency.
817 *********************************************************************************
820 int waitForInterruptSys (int pin, int mS)
824 struct pollfd polls ;
826 if ((fd = sysFds [pin & 63]) == -1)
831 x = read (fd, buf, 6) ;
837 lseek (fd, 0, SEEK_SET) ;
839 // Setup poll structure
842 polls.events = POLLPRI ; // Urgent data!
846 return poll (&polls, 1, mS) ;
849 int waitForInterruptWPi (int pin, int mS)
851 return waitForInterruptSys (pinToGpio [pin & 63], mS) ;
854 int waitForInterruptGpio (int pin, int mS)
856 return waitForInterruptSys (pin, mS) ;
862 * Wait for some number of milli seconds
863 *********************************************************************************
866 void delay (unsigned int howLong)
868 struct timespec sleeper, dummy ;
870 sleeper.tv_sec = (time_t)(howLong / 1000) ;
871 sleeper.tv_nsec = (long)(howLong % 1000) * 1000000 ;
873 nanosleep (&sleeper, &dummy) ;
879 * This is somewhat intersting. It seems that on the Pi, a single call
880 * to nanosleep takes some 80 to 130 microseconds anyway, so while
881 * obeying the standards (may take longer), it's not always what we
884 * So what I'll do now is if the delay is less than 100uS we'll do it
885 * in a hard loop, watching a built-in counter on the ARM chip. This is
886 * somewhat sub-optimal in that it uses 100% CPU, something not an issue
887 * in a microcontroller, but under a multi-tasking, multi-user OS, it's
888 * wastefull, however we've no real choice )-:
889 *********************************************************************************
892 void delayMicrosecondsSys (unsigned int howLong)
894 struct timespec sleeper, dummy ;
897 sleeper.tv_nsec = (long)(howLong * 1000) ;
899 nanosleep (&sleeper, &dummy) ;
902 void delayMicrosecondsHard (unsigned int howLong)
904 *(timer + TIMER_LOAD) = howLong ;
905 *(timer + TIMER_IRQ_CLR) = 0 ;
907 while (*timerIrqRaw == 0)
911 void delayMicrosecondsWPi (unsigned int howLong)
913 struct timespec sleeper, dummy ;
915 /**/ if (howLong == 0)
917 else if (howLong < 100)
918 delayMicrosecondsHard (howLong) ;
922 sleeper.tv_nsec = (long)(howLong * 1000) ;
923 nanosleep (&sleeper, &dummy) ;
930 * Return a number of milliseconds as an unsigned int.
931 *********************************************************************************
934 unsigned int millis (void)
937 unsigned long long t1 ;
939 gettimeofday (&tv, NULL) ;
941 t1 = (tv.tv_sec * 1000000 + tv.tv_usec) / 1000 ;
943 return (uint32_t)(t1 - epoch) ;
949 * Must be called once at the start of your program execution.
951 * Default setup: Initialises the system into wiringPi Pin mode and uses the
952 * memory mapped hardware directly.
953 *********************************************************************************
956 int wiringPiSetup (void)
960 uint8_t *gpioMem, *pwmMem, *clkMem, *padsMem, *timerMem ;
963 if (getenv ("WIRINGPI_DEBUG") != NULL)
964 wiringPiDebug = TRUE ;
967 printf ("wiringPi: wiringPiSetup called\n") ;
969 pinMode = pinModeWPi ;
970 pullUpDnControl = pullUpDnControlWPi ;
971 digitalWrite = digitalWriteWPi ;
972 pwmWrite = pwmWriteWPi ;
973 setPadDrive = setPadDriveWPi ;
974 digitalRead = digitalReadWPi ;
975 waitForInterrupt = waitForInterruptWPi ;
976 delayMicroseconds = delayMicrosecondsWPi ;
977 pwmSetMode = pwmSetModeWPi ;
978 pwmSetRange = pwmSetRangeWPi ;
979 pwmSetClock = pwmSetClockWPi ;
981 if ((boardRev = piBoardRev ()) < 0)
985 pinToGpio = pinToGpioR1 ;
987 pinToGpio = pinToGpioR2 ;
989 // Open the master /dev/memory device
991 if ((fd = open ("/dev/mem", O_RDWR | O_SYNC) ) < 0)
993 fprintf (stderr, "wiringPiSetup: Unable to open /dev/mem: %s\n", strerror (errno)) ;
999 // Allocate 2 pages - 1 ...
1001 if ((gpioMem = malloc (BLOCK_SIZE + (PAGE_SIZE-1))) == NULL)
1003 fprintf (stderr, "wiringPiSetup: malloc failed: %s\n", strerror (errno)) ;
1007 // ... presumably to make sure we can round it up to a whole page size
1009 if (((uint32_t)gpioMem % PAGE_SIZE) != 0)
1010 gpioMem += PAGE_SIZE - ((uint32_t)gpioMem % PAGE_SIZE) ;
1012 gpio = (uint32_t *)mmap((caddr_t)gpioMem, BLOCK_SIZE, PROT_READ|PROT_WRITE, MAP_SHARED|MAP_FIXED, fd, GPIO_BASE) ;
1014 if ((int32_t)gpio < 0)
1016 fprintf (stderr, "wiringPiSetup: mmap failed: %s\n", strerror (errno)) ;
1022 if ((pwmMem = malloc (BLOCK_SIZE + (PAGE_SIZE-1))) == NULL)
1024 fprintf (stderr, "wiringPiSetup: pwmMem malloc failed: %s\n", strerror (errno)) ;
1028 if (((uint32_t)pwmMem % PAGE_SIZE) != 0)
1029 pwmMem += PAGE_SIZE - ((uint32_t)pwmMem % PAGE_SIZE) ;
1031 pwm = (uint32_t *)mmap(pwmMem, BLOCK_SIZE, PROT_READ|PROT_WRITE, MAP_SHARED|MAP_FIXED, fd, GPIO_PWM) ;
1033 if ((int32_t)pwm < 0)
1035 fprintf (stderr, "wiringPiSetup: mmap failed (pwm): %s\n", strerror (errno)) ;
1039 // Clock control (needed for PWM)
1041 if ((clkMem = malloc (BLOCK_SIZE + (PAGE_SIZE-1))) == NULL)
1043 fprintf (stderr, "wiringPiSetup: clkMem malloc failed: %s\n", strerror (errno)) ;
1047 if (((uint32_t)clkMem % PAGE_SIZE) != 0)
1048 clkMem += PAGE_SIZE - ((uint32_t)clkMem % PAGE_SIZE) ;
1050 clk = (uint32_t *)mmap(clkMem, BLOCK_SIZE, PROT_READ|PROT_WRITE, MAP_SHARED|MAP_FIXED, fd, CLOCK_BASE) ;
1052 if ((int32_t)clk < 0)
1054 fprintf (stderr, "wiringPiSetup: mmap failed (clk): %s\n", strerror (errno)) ;
1060 if ((padsMem = malloc (BLOCK_SIZE + (PAGE_SIZE-1))) == NULL)
1062 fprintf (stderr, "wiringPiSetup: padsMem malloc failed: %s\n", strerror (errno)) ;
1066 if (((uint32_t)padsMem % PAGE_SIZE) != 0)
1067 padsMem += PAGE_SIZE - ((uint32_t)padsMem % PAGE_SIZE) ;
1069 pads = (uint32_t *)mmap(padsMem, BLOCK_SIZE, PROT_READ|PROT_WRITE, MAP_SHARED|MAP_FIXED, fd, GPIO_PADS) ;
1071 if ((int32_t)pads < 0)
1073 fprintf (stderr, "wiringPiSetup: mmap failed (pads): %s\n", strerror (errno)) ;
1078 printf ("Checking pads @ 0x%08X\n", (unsigned int)pads) ;
1079 printf (" -> %08X %08X %08X\n", *(pads + 11), *(pads + 12), *(pads + 13)) ;
1084 if ((timerMem = malloc (BLOCK_SIZE + (PAGE_SIZE-1))) == NULL)
1086 fprintf (stderr, "wiringPiSetup: timerMem malloc failed: %s\n", strerror (errno)) ;
1090 if (((uint32_t)timerMem % PAGE_SIZE) != 0)
1091 timerMem += PAGE_SIZE - ((uint32_t)timerMem % PAGE_SIZE) ;
1093 timer = (uint32_t *)mmap(timerMem, BLOCK_SIZE, PROT_READ|PROT_WRITE, MAP_SHARED|MAP_FIXED, fd, GPIO_TIMER) ;
1095 if ((int32_t)timer < 0)
1097 fprintf (stderr, "wiringPiSetup: mmap failed (timer): %s\n", strerror (errno)) ;
1101 // Set the timer to free-running, 1MHz.
1102 // 0xF9 is 249, the timer divide is base clock / (divide+1)
1103 // so base clock is 250MHz / 250 = 1MHz.
1105 *(timer + TIMER_CONTROL) = 0x0000280 ;
1106 *(timer + TIMER_PRE_DIV) = 0x00000F9 ;
1107 timerIrqRaw = timer + TIMER_IRQ_RAW ;
1109 // Initialise our epoch for millis()
1111 gettimeofday (&tv, NULL) ;
1112 epoch = (tv.tv_sec * 1000000 + tv.tv_usec) / 1000 ;
1119 * wiringPiSetupGpio:
1120 * Must be called once at the start of your program execution.
1122 * GPIO setup: Initialises the system into GPIO Pin mode and uses the
1123 * memory mapped hardware directly.
1124 *********************************************************************************
1127 int wiringPiSetupGpio (void)
1132 printf ("wiringPi: wiringPiSetupGpio called\n") ;
1134 if ((x = wiringPiSetup ()) < 0)
1137 pinMode = pinModeGpio ;
1138 pullUpDnControl = pullUpDnControlGpio ;
1139 digitalWrite = digitalWriteGpio ;
1140 pwmWrite = pwmWriteGpio ;
1141 setPadDrive = setPadDriveGpio ;
1142 digitalRead = digitalReadGpio ;
1143 waitForInterrupt = waitForInterruptGpio ;
1144 delayMicroseconds = delayMicrosecondsWPi ; // Same
1145 pwmSetMode = pwmSetModeWPi ;
1146 pwmSetRange = pwmSetRangeWPi ;
1147 pwmSetClock = pwmSetClockWPi ;
1155 * Must be called once at the start of your program execution.
1157 * Initialisation (again), however this time we are using the /sys/class/gpio
1158 * interface to the GPIO systems - slightly slower, but always usable as
1159 * a non-root user, assuming the devices are already exported and setup correctly.
1162 int wiringPiSetupSys (void)
1169 printf ("wiringPi: wiringPiSetupSys called\n") ;
1171 pinMode = pinModeSys ;
1172 pullUpDnControl = pullUpDnControlSys ;
1173 digitalWrite = digitalWriteSys ;
1174 pwmWrite = pwmWriteSys ;
1175 setPadDrive = setPadDriveSys ;
1176 digitalRead = digitalReadSys ;
1177 waitForInterrupt = waitForInterruptSys ;
1178 delayMicroseconds = delayMicrosecondsSys ;
1179 pwmSetMode = pwmSetModeSys ;
1180 pwmSetRange = pwmSetRangeSys ;
1181 pwmSetClock = pwmSetClockSys ;
1184 // Open and scan the directory, looking for exported GPIOs, and pre-open
1185 // the 'value' interface to speed things up for later
1187 for (pin = 0 ; pin < 64 ; ++pin)
1189 sprintf (fName, "/sys/class/gpio/gpio%d/value", pin) ;
1190 sysFds [pin] = open (fName, O_RDWR) ;
1193 // Initialise the epoch for mills() ...
1195 gettimeofday (&tv, NULL) ;
1196 epoch = (tv.tv_sec * 1000000 + tv.tv_usec) / 1000 ;