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Added a clock mode to enable the GPIo pins to be set with
one of the GPCLK drivers to generate a frequency up to
19.2MHz.

Tidied some code up and added the clock functions into the gpio
utility.

Gordon Henderson 11 years ago
parent
commit
56c77b5a2e
4 changed files with 247 additions and 133 deletions
  1. 8 2
      gpio/gpio.1
  2. 38 9
      gpio/gpio.c
  3. 195 122
      wiringPi/wiringPi.c
  4. 6 0
      wiringPi/wiringPi.h

+ 8 - 2
gpio/gpio.1

@@ -9,7 +9,7 @@ gpio \- Command-line access to Raspberry Pi and PiFace GPIO
 .PP
 .B gpio
 .B [ \-g ]
-.B read/write/wb/pwm/mode ...
+.B read/write/wb/pwm/clock/mode ...
 .PP
 .B gpio
 .B [ \-p ]
@@ -104,7 +104,13 @@ mode.
 
 .TP
 .B pwm <pin> <value>
-Write a PWM value (0-1023) to the given pin.
+Write a PWM value (0-1023) to the given pin. The pin needs to be put
+into PWM mode first.
+
+.TP
+.B clock <pin> <frequency>
+Set the output frequency on the given pin. The pin needs to be put into
+clock mode first.
 
 .TP
 .B mode <pin> <mode>

+ 38 - 9
gpio/gpio.c

@@ -42,13 +42,13 @@ extern int wiringPiDebug ;
 #  define	FALSE	(1==2)
 #endif
 
-#define	VERSION	"1.10"
+#define	VERSION	"1.11"
 
 static int wpMode ;
 
 char *usage = "Usage: gpio -v\n"
               "       gpio -h\n"
-              "       gpio [-g] <read/write/wb/pwm/mode> ...\n"
+              "       gpio [-g] <read/write/wb/pwm/clock/mode> ...\n"
               "       gpio [-p] <read/write/wb> ...\n"
 	      "       gpio readall\n"
 	      "       gpio unexportall/exports ...\n"
@@ -541,15 +541,16 @@ void doMode (int argc, char *argv [])
 
   mode = argv [3] ;
 
-  /**/ if (strcasecmp (mode, "in")   == 0) pinMode         (pin, INPUT) ;
-  else if (strcasecmp (mode, "out")  == 0) pinMode         (pin, OUTPUT) ;
-  else if (strcasecmp (mode, "pwm")  == 0) pinMode         (pin, PWM_OUTPUT) ;
-  else if (strcasecmp (mode, "up")   == 0) pullUpDnControl (pin, PUD_UP) ;
-  else if (strcasecmp (mode, "down") == 0) pullUpDnControl (pin, PUD_DOWN) ;
-  else if (strcasecmp (mode, "tri")  == 0) pullUpDnControl (pin, PUD_OFF) ;
+  /**/ if (strcasecmp (mode, "in")     == 0) pinMode         (pin, INPUT) ;
+  else if (strcasecmp (mode, "out")    == 0) pinMode         (pin, OUTPUT) ;
+  else if (strcasecmp (mode, "pwm")    == 0) pinMode         (pin, PWM_OUTPUT) ;
+  else if (strcasecmp (mode, "clock")  == 0) pinMode         (pin, GPIO_CLOCK) ;
+  else if (strcasecmp (mode, "up")     == 0) pullUpDnControl (pin, PUD_UP) ;
+  else if (strcasecmp (mode, "down")   == 0) pullUpDnControl (pin, PUD_DOWN) ;
+  else if (strcasecmp (mode, "tri")    == 0) pullUpDnControl (pin, PUD_OFF) ;
   else
   {
-    fprintf (stderr, "%s: Invalid mode: %s. Should be in/out/pwm/up/down/tri\n", argv [1], mode) ;
+    fprintf (stderr, "%s: Invalid mode: %s. Should be in/out/pwm/clock/up/down/tri\n", argv [1], mode) ;
     exit (1) ;
   }
 }
@@ -754,6 +755,33 @@ void doRead (int argc, char *argv [])
 }
 
 
+/*
+ * doClock:
+ *	Output a clock on a pin
+ *********************************************************************************
+ */
+
+void doClock (int argc, char *argv [])
+{
+  int pin, freq ;
+
+  if (argc != 4)
+  {
+    fprintf (stderr, "Usage: %s clock <pin> <freq>\n", argv [0]) ;
+    exit (1) ;
+  }
+
+  pin = atoi (argv [2]) ;
+
+  if ((wpMode == WPI_MODE_PINS) && ((pin < 0) || (pin >= NUM_PINS)))
+    return ;
+
+  freq = atoi (argv [3]) ;
+
+  gpioClockSet (pin, freq) ;
+}
+
+
 /*
  * doPwm:
  *	Output a PWM value on a pin
@@ -980,6 +1008,7 @@ int main (int argc, char *argv [])
   else if (strcasecmp (argv [1], "write")    == 0) doWrite     (argc, argv) ;
   else if (strcasecmp (argv [1], "wb")       == 0) doWriteByte (argc, argv) ;
   else if (strcasecmp (argv [1], "pwm"  )    == 0) doPwm       (argc, argv) ;
+  else if (strcasecmp (argv [1], "clock")    == 0) doClock     (argc, argv) ;
   else if (strcasecmp (argv [1], "mode" )    == 0) doMode      (argc, argv) ;
   else
   {

+ 195 - 122
wiringPi/wiringPi.c

@@ -79,6 +79,7 @@ void (*pullUpDnControl)   (int pin, int pud) ;
 void (*digitalWrite)      (int pin, int value) ;
 void (*digitalWriteByte)  (int value) ;
 void (*pwmWrite)          (int pin, int value) ;
+void (*gpioClockSet)      (int pin, int value) ;
 void (*setPadDrive)       (int group, int value) ;
 int  (*digitalRead)       (int pin) ;
 int  (*waitForInterrupt)  (int pin, int mS) ;
@@ -97,6 +98,24 @@ void (*pwmSetClock)       (int divisor) ;
 #define	BCM_PASSWORD		0x5A000000
 
 
+// The BCM2835 has 54 GPIO pins.
+//	BCM2835 data sheet, Page 90 onwards.
+//	There are 6 control registers, each control the functions of a block
+//	of 10 pins.
+//	Each control register has 10 sets of 3 bits per GPIO pin - the ALT values
+//
+//	000 = GPIO Pin X is an input
+//	001 = GPIO Pin X is an output
+//	100 = GPIO Pin X takes alternate function 0
+//	101 = GPIO Pin X takes alternate function 1
+//	110 = GPIO Pin X takes alternate function 2
+//	111 = GPIO Pin X takes alternate function 3
+//	011 = GPIO Pin X takes alternate function 4
+//	010 = GPIO Pin X takes alternate function 5
+//
+// So the 3 bits for port X are:
+//	X / 10 + ((X % 10) * 3)
+
 // Port function select bits
 
 #define	FSEL_INPT		0b000
@@ -110,20 +129,21 @@ void (*pwmSetClock)       (int divisor) ;
 #define	FSEL_ALT5		0b010
 
 // Access from ARM Running Linux
-//	Take from Gert/Doms code. Some of this is not in the manual
+//	Taken from Gert/Doms code. Some of this is not in the manual
 //	that I can find )-:
 
-#define BCM2708_PERI_BASE	                   0x20000000
-#define GPIO_PADS		(BCM2708_PERI_BASE + 0x100000)
-#define CLOCK_BASE		(BCM2708_PERI_BASE + 0x101000)
-#define GPIO_BASE		(BCM2708_PERI_BASE + 0x200000)
-#define GPIO_TIMER		(BCM2708_PERI_BASE + 0x00B000)
-#define GPIO_PWM		(BCM2708_PERI_BASE + 0x20C000)
+#define BCM2708_PERI_BASE	                     0x20000000
+#define GPIO_PADS		(BCM2708_PERI_BASE + 0x00100000)
+#define CLOCK_BASE		(BCM2708_PERI_BASE + 0x00101000)
+#define GPIO_BASE		(BCM2708_PERI_BASE + 0x00200000)
+#define GPIO_TIMER		(BCM2708_PERI_BASE + 0x0000B000)
+#define GPIO_PWM		(BCM2708_PERI_BASE + 0x0020C000)
 
 #define	PAGE_SIZE		(4*1024)
 #define	BLOCK_SIZE		(4*1024)
 
 // PWM
+//	Word offsets into the PWM control region
 
 #define	PWM_CONTROL 0
 #define	PWM_STATUS  1
@@ -132,17 +152,11 @@ void (*pwmSetClock)       (int divisor) ;
 #define	PWM1_RANGE  8
 #define	PWM1_DATA   9
 
+//	Clock regsiter offsets
+
 #define	PWMCLK_CNTL	40
 #define	PWMCLK_DIV	41
 
-#define	PWM1_MS_MODE    0x8000  // Run in MS mode
-#define	PWM1_USEFIFO    0x2000  // Data from FIFO
-#define	PWM1_REVPOLAR   0x1000  // Reverse polarity
-#define	PWM1_OFFSTATE   0x0800  // Ouput Off state
-#define	PWM1_REPEATFF   0x0400  // Repeat last value if FIFO empty
-#define	PWM1_SERIAL     0x0200  // Run in serial mode
-#define	PWM1_ENABLE     0x0100  // Channel Enable
-
 #define	PWM0_MS_MODE    0x0080  // Run in MS mode
 #define	PWM0_USEFIFO    0x0020  // Data from FIFO
 #define	PWM0_REVPOLAR   0x0010  // Reverse polarity
@@ -151,7 +165,16 @@ void (*pwmSetClock)       (int divisor) ;
 #define	PWM0_SERIAL     0x0002  // Run in serial mode
 #define	PWM0_ENABLE     0x0001  // Channel Enable
 
+#define	PWM1_MS_MODE    0x8000  // Run in MS mode
+#define	PWM1_USEFIFO    0x2000  // Data from FIFO
+#define	PWM1_REVPOLAR   0x1000  // Reverse polarity
+#define	PWM1_OFFSTATE   0x0800  // Ouput Off state
+#define	PWM1_REPEATFF   0x0400  // Repeat last value if FIFO empty
+#define	PWM1_SERIAL     0x0200  // Run in serial mode
+#define	PWM1_ENABLE     0x0100  // Channel Enable
+
 // Timer
+//	Word offsets
 
 #define	TIMER_LOAD	(0x400 >> 2)
 #define	TIMER_VALUE	(0x404 >> 2)
@@ -184,24 +207,6 @@ static int wiringPiMode = WPI_MODE_UNINITIALISED ;
 
 int wiringPiDebug = FALSE ;
 
-// The BCM2835 has 54 GPIO pins.
-//	BCM2835 data sheet, Page 90 onwards.
-//	There are 6 control registers, each control the functions of a block
-//	of 10 pins.
-//	Each control register has 10 sets of 3 bits per GPIO pin:
-//
-//	000 = GPIO Pin X is an input
-//	001 = GPIO Pin X is an output
-//	100 = GPIO Pin X takes alternate function 0
-//	101 = GPIO Pin X takes alternate function 1
-//	110 = GPIO Pin X takes alternate function 2
-//	111 = GPIO Pin X takes alternate function 3
-//	011 = GPIO Pin X takes alternate function 4
-//	010 = GPIO Pin X takes alternate function 5
-//
-// So the 3 bits for port X are:
-//	X / 10 + ((X % 10) * 3)
-
 // sysFds:
 //	Map a file descriptor from the /sys/class/gpio/gpioX/value
 
@@ -341,11 +346,14 @@ static uint8_t gpioToFEN [] =
 #endif
 
 
-// gpioToPUDCLK
-//	(Word) offset to the Pull Up Down Clock regsiter
+// GPPUD:
+//	GPIO Pin pull up/down register
 
 #define	GPPUD	37
 
+// gpioToPUDCLK
+//	(Word) offset to the Pull Up Down Clock regsiter
+
 static uint8_t gpioToPUDCLK [] =
 {
   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,
@@ -368,6 +376,9 @@ static uint8_t gpioToPwmALT [] =
           0,         0,         0,         0,         0,         0,         0,         0,	// 56 -> 63
 } ;
 
+// gpioToPwmPort
+//	The port value to put a GPIO pin into PWM mode
+
 static uint8_t gpioToPwmPort [] =
 {
           0,         0,         0,         0,         0,         0,         0,         0,	//  0 ->  7
@@ -381,6 +392,55 @@ static uint8_t gpioToPwmPort [] =
 
 } ;
 
+// gpioToGpClkALT:
+//	ALT value to put a GPIO pin into GP Clock mode.
+//	On the Pi we can really only use BCM_GPIO_4 and BCM_GPIO_21
+//	for clocks 0 and 1 respectivey, however I'll include the full
+//	list for completeness - maybe one day...
+
+#define	GPIO_CLOCK_SOURCE	1
+
+// gpioToGpClkALT0:
+
+static uint8_t gpioToGpClkALT0 [] =
+{
+          0,         0,         0,         0, FSEL_ALT0, FSEL_ALT0, FSEL_ALT0,         0,	//  0 ->  7
+          0,         0,         0,         0,         0,         0,         0,         0, 	//  8 -> 15
+          0,         0,         0,         0, FSEL_ALT5, FSEL_ALT5,         0,         0, 	// 16 -> 23
+          0,         0,         0,         0,         0,         0,         0,         0,	// 24 -> 31
+  FSEL_ALT0,         0, FSEL_ALT0,         0,         0,         0,         0,         0,	// 32 -> 39
+          0,         0, FSEL_ALT0, FSEL_ALT0, FSEL_ALT0,         0,         0,         0,	// 40 -> 47
+          0,         0,         0,         0,         0,         0,         0,         0,	// 48 -> 55
+          0,         0,         0,         0,         0,         0,         0,         0,	// 56 -> 63
+} ;
+
+// gpioToClk:
+//	(word) Offsets to the clock Control and Divisor register
+
+static uint8_t gpioToClkCon [] =
+{
+         -1,        -1,        -1,        -1,        28,        30,        32,        -1,	//  0 ->  7
+         -1,        -1,        -1,        -1,        -1,        -1,        -1,        -1, 	//  8 -> 15
+         -1,        -1,        -1,        -1,        28,        30,        -1,        -1, 	// 16 -> 23
+         -1,        -1,        -1,        -1,        -1,        -1,        -1,        -1,	// 24 -> 31
+         28,        -1,        28,        -1,        -1,        -1,        -1,        -1,	// 32 -> 39
+         -1,        -1,        28,        30,        28,        -1,        -1,        -1,	// 40 -> 47
+         -1,        -1,        -1,        -1,        -1,        -1,        -1,        -1,	// 48 -> 55
+         -1,        -1,        -1,        -1,        -1,        -1,        -1,        -1,	// 56 -> 63
+} ;
+
+static uint8_t gpioToClkDiv [] =
+{
+         -1,        -1,        -1,        -1,        29,        31,        33,        -1,	//  0 ->  7
+         -1,        -1,        -1,        -1,        -1,        -1,        -1,        -1, 	//  8 -> 15
+         -1,        -1,        -1,        -1,        29,        31,        -1,        -1, 	// 16 -> 23
+         -1,        -1,        -1,        -1,        -1,        -1,        -1,        -1,	// 24 -> 31
+         29,        -1,        29,        -1,        -1,        -1,        -1,        -1,	// 32 -> 39
+         -1,        -1,        29,        31,        29,        -1,        -1,        -1,	// 40 -> 47
+         -1,        -1,        -1,        -1,        -1,        -1,        -1,        -1,	// 48 -> 55
+         -1,        -1,        -1,        -1,        -1,        -1,        -1,        -1,	// 56 -> 63
+} ;
+
 
 /*
  * Functions
@@ -496,93 +556,6 @@ int piBoardRev (void)
 
 
 
-/*
- * pinMode:
- *	Sets the mode of a pin to be input, output or PWM output
- *********************************************************************************
- */
-
-void pinModeGpio (int pin, int mode)
-{
-//  register int barrier ;
-
-  int fSel, shift, alt ;
-
-  pin &= 63 ;
-
-  fSel    = gpioToGPFSEL [pin] ;
-  shift   = gpioToShift  [pin] ;
-
-  /**/ if (mode == INPUT)
-    *(gpio + fSel) = (*(gpio + fSel) & ~(7 << shift)) ; // Sets bits to zero = input
-  else if (mode == OUTPUT)
-    *(gpio + fSel) = (*(gpio + fSel) & ~(7 << shift)) | (1 << shift) ;
-  else if (mode == PWM_OUTPUT)
-  {
-    if ((alt = gpioToPwmALT [pin]) == 0)	// Not a PWM pin
-      return ;
-
-// Set pin to PWM mode
-
-    *(gpio + fSel) = (*(gpio + fSel) & ~(7 << shift)) | (alt << shift) ;
-
-    delayMicroseconds (110) ;				// See comments in pwmSetClockWPi
-    *(gpio + fSel) = (*(gpio + fSel) & ~(7 << shift)) | (alt << shift) ;
-
-//  Page 107 of the BCM Peripherals manual talks about the GPIO clocks,
-//	but I'm assuming (hoping!) that this applies to other clocks too.
-
-    *(pwm + PWM_CONTROL) = 0 ;				// Stop PWM
-
-    *(clk + PWMCLK_CNTL) = BCM_PASSWORD | 0x01 ;	// Stop PWM Clock
-    delayMicroseconds (110) ;				// See comments in pwmSetClockWPi
-
-    while ((*(clk + PWMCLK_CNTL) & 0x80) != 0)		// Wait for clock to be !BUSY
-      delayMicroseconds (1) ;
-
-    *(clk + PWMCLK_DIV)  = BCM_PASSWORD | (32 << 12) ;	// set pwm div to 32 (19.2/32 = 600KHz)
-    *(clk + PWMCLK_CNTL) = BCM_PASSWORD | 0x11 ;	// enable clk
-
-    delayMicroseconds (110) ;				// See comments in pwmSetClockWPi
-
-// Default range register of 1024
-
-    *(pwm + PWM0_RANGE) = 1024 ; delayMicroseconds (10) ;
-    *(pwm + PWM1_RANGE) = 1024 ; delayMicroseconds (10) ;
-    *(pwm + PWM0_DATA)  =    0 ; delayMicroseconds (10) ;
-    *(pwm + PWM1_DATA)  =    0 ; delayMicroseconds (10) ;
-
-// Enable PWMs in balanced mode (default)
-
-    *(pwm + PWM_CONTROL) = PWM0_ENABLE | PWM1_ENABLE ;
-
-    delay (100) ;
-  }
-
-
-// When we change mode of any pin, we remove the pull up/downs
-//	Or we used to... Hm. Commented out now because for some wieird reason,
-//	it seems to block subsequent attempts to set the pull up/downs and I've
-//	not quite gotten to the bottom of why this happens
-//	The down-side is that the pull up/downs are rememberd in the SoC between
-//	power cycles, so it's going to be a good idea to explicitly set them in
-//	any new code.
-//
-//  pullUpDnControl (pin, PUD_OFF) ;
-
-}
-
-void pinModeWPi (int pin, int mode)
-{
-  pinModeGpio (pinToGpio [pin & 63], mode) ;
-}
-
-void pinModeSys (int pin, int mode)
-{
-  return ;
-}
-
-
 /*
  * getAlt:
  *	Returns the ALT bits for a given port. Only really of-use
@@ -824,6 +797,44 @@ void pwmWriteSys (int pin, int value)
 }
 
 
+/*
+ * gpioClockSet:
+ *	Set the freuency on a GPIO clock pin
+ *********************************************************************************
+ */
+
+void gpioClockSetGpio (int pin, int freq)
+{
+  int divi, divr, divf ;
+
+  pin &= 63 ;
+  
+  divi = 19200000 / freq ;
+  divr = 19200000 % freq ;
+  divf = (int)((double)divr * 4096.0 / 19200000.0) ;
+
+  if (divi > 4095)
+    divi = 4095 ;
+
+  *(clk + gpioToClkCon [pin]) = BCM_PASSWORD | GPIO_CLOCK_SOURCE ;		// Stop GPIO Clock
+  while ((*(clk + gpioToClkCon [pin]) & 0x80) != 0)				// ... and wait
+    ;
+
+  *(clk + gpioToClkDiv [pin]) = BCM_PASSWORD | (divi << 12) | divf ;		// Set dividers
+  *(clk + gpioToClkCon [pin]) = BCM_PASSWORD | 0x10 | GPIO_CLOCK_SOURCE ;	// Start Clock
+}
+
+void gpioClockSetWPi (int pin, int freq)
+{
+  gpioClockSetGpio (pinToGpio [pin & 63], freq) ;
+}
+
+void gpioClockSetSys (int pin, int freq)
+{
+  return ;
+}
+
+
 /*
  * setPadDrive:
  *	Set the PAD driver value
@@ -931,6 +942,65 @@ void pullUpDnControlSys (int pin, int pud)
 }
 
 
+/*
+ * pinMode:
+ *	Sets the mode of a pin to be input, output or PWM output
+ *********************************************************************************
+ */
+
+void pinModeGpio (int pin, int mode)
+{
+//  register int barrier ;
+
+  int fSel, shift, alt ;
+
+  pin &= 63 ;
+
+  fSel    = gpioToGPFSEL [pin] ;
+  shift   = gpioToShift  [pin] ;
+
+  /**/ if (mode == INPUT)
+    *(gpio + fSel) = (*(gpio + fSel) & ~(7 << shift)) ; // Sets bits to zero = input
+  else if (mode == OUTPUT)
+    *(gpio + fSel) = (*(gpio + fSel) & ~(7 << shift)) | (1 << shift) ;
+  else if (mode == PWM_OUTPUT)
+  {
+    if ((alt = gpioToPwmALT [pin]) == 0)	// Not a PWM pin
+      return ;
+
+// Set pin to PWM mode
+
+    *(gpio + fSel) = (*(gpio + fSel) & ~(7 << shift)) | (alt << shift) ;
+    delayMicroseconds (110) ;		// See comments in pwmSetClockWPi
+
+    pwmSetModeWPi  (PWM_MODE_BAL) ;	// Pi default mode
+    pwmSetRangeWPi (1024) ;		// Default range of 1024
+    pwmSetClockWPi (32) ;		// 19.2 / 32 = 600KHz - Also starts the PWM
+  }
+  else if (mode == GPIO_CLOCK)
+  {
+    if ((alt = gpioToGpClkALT0 [pin]) == 0)	// Not a GPIO_CLOCK pin
+      return ;
+
+// Set pin to GPIO_CLOCK mode and set the clock frequency to 100KHz
+
+    *(gpio + fSel) = (*(gpio + fSel) & ~(7 << shift)) | (alt << shift) ;
+    delayMicroseconds (110) ;
+    gpioClockSetGpio (pin, 100000) ;
+  }
+}
+
+void pinModeWPi (int pin, int mode)
+{
+  pinModeGpio (pinToGpio [pin & 63], mode) ;
+}
+
+void pinModeSys (int pin, int mode)
+{
+  return ;
+}
+
+
 /*
  * waitForInterrupt:
  *	Wait for Interrupt on a GPIO pin.
@@ -1229,6 +1299,7 @@ int wiringPiSetup (void)
     pullUpDnControl =   pullUpDnControlWPi ;
        digitalWrite =      digitalWriteWPi ;
    digitalWriteByte = digitalWriteByteGpio ;	// Same code
+       gpioClockSet =      gpioClockSetWPi ;
            pwmWrite =          pwmWriteWPi ;
         setPadDrive =       setPadDriveWPi ;
         digitalRead =       digitalReadWPi ;
@@ -1373,6 +1444,7 @@ int wiringPiSetupGpio (void)
     pullUpDnControl =   pullUpDnControlGpio ;
        digitalWrite =      digitalWriteGpio ;
    digitalWriteByte =  digitalWriteByteGpio ;
+       gpioClockSet =      gpioClockSetGpio ;
            pwmWrite =          pwmWriteGpio ;
         setPadDrive =       setPadDriveGpio ;
         digitalRead =       digitalReadGpio ;
@@ -1413,6 +1485,7 @@ int wiringPiSetupSys (void)
     pullUpDnControl =   pullUpDnControlSys ;
        digitalWrite =      digitalWriteSys ;
    digitalWriteByte =  digitalWriteByteSys ;
+       gpioClockSet =      gpioClockSetSys ;
            pwmWrite =          pwmWriteSys ;
         setPadDrive =       setPadDriveSys ;
         digitalRead =       digitalReadSys ;

+ 6 - 0
wiringPi/wiringPi.h

@@ -32,13 +32,18 @@
 #define	WPI_MODE_PIFACE		 3
 #define	WPI_MODE_UNINITIALISED	-1
 
+// Pin modes
+
 #define	INPUT			 0
 #define	OUTPUT			 1
 #define	PWM_OUTPUT		 2
+#define	GPIO_CLOCK		 3
 
 #define	LOW			 0
 #define	HIGH			 1
 
+// Pull up/down/none
+
 #define	PUD_OFF			 0
 #define	PUD_DOWN		 1
 #define	PUD_UP			 2
@@ -85,6 +90,7 @@ extern int  (*getAlt)            (int pin) ;
 extern void (*pullUpDnControl)   (int pin, int pud) ;
 extern void (*digitalWrite)      (int pin, int value) ;
 extern void (*digitalWriteByte)  (int value) ;
+extern void (*gpioClockSet)      (int pin, int freq) ;
 extern void (*pwmWrite)          (int pin, int value) ;
 extern void (*setPadDrive)       (int group, int value) ;
 extern int  (*digitalRead)       (int pin) ;