// bcm2835.h // // C and C++ support for Broadcom BCM 2835 as used in Raspberry Pi // http://elinux.org/RPi_Low-level_peripherals // http://www.raspberrypi.org/wp-content/uploads/2012/02/BCM2835-ARM-Peripherals.pdf // // Author: Mike McCauley (mikem@open.com.au) // Copyright (C) 2011 Mike McCauley // $Id: bcm2835.h,v 1.4 2012/07/16 23:57:59 mikem Exp mikem $ // /// \mainpage C library for Broadcom BCM 2835 as used in Raspberry Pi /// /// This is a C library for Raspberry Pi (RPi). It provides access to /// GPIO and other IO functions on the Broadcom BCM 2835 chip, /// allowing access to the GPIO pins on the /// 26 pin IDE plug on the RPi board so you can control and interface with various external devices. /// /// It provides functions for reading digital inputs and setting digital outputs. /// Pin event detection is supported by polling (interrupts not supported). /// /// It is C++ compatible, and installs as a header file and non-shared library on /// any Linux-based distro (but clearly is no use except on Raspberry Pi or another board with /// BCM 2835). /// /// The latest version of this documentation can be downloaded from /// http://www.open.com.au/mikem/bcm2835 /// /// The version of the package that this documentation refers to can be downloaded /// from http://www.open.com.au/mikem/bcm2835/bcm2835-1.12.tar.gz /// You can find the latest version at http://www.open.com.au/mikem/bcm2835 /// /// Several example programs are provided. /// /// Based on data in http://elinux.org/RPi_Low-level_peripherals and /// http://www.raspberrypi.org/wp-content/uploads/2012/02/BCM2835-ARM-Peripherals.pdf /// and http://www.scribd.com/doc/101830961/GPIO-Pads-Control2 /// /// You can also find online help and discussion at http://groups.google.com/group/bcm2835 /// Please use that group for all questions and discussions on this topic. /// Do not contact the author directly, unless it is to discuss commercial licensing. /// /// Tested on debian6-19-04-2012, 2012-07-15-wheezy-raspbian and Occidentalisv01 /// CAUTION: it has been observed that when detect enables such as bcm2835_gpio_len() /// are used and the pin is pulled LOW /// it can cause temporary hangs on 2012-07-15-wheezy-raspbian and Occidentalisv01. /// Reason for this is not yet determined, but suspect that an interrupt handler is /// hitting a hard loop on those OSs. /// If you must use bcm2835_gpio_len() and friends, make sure you disable the pins with /// bcm2835_gpio_cler_len() and friends after use. /// /// \par Installation /// /// This library consists of a single non-shared library and header file, which will be /// installed in the usual places by make install /// /// tar zxvf bcm2835-1.0.tar.gz /// cd bcm2835-1.0 /// ./configure /// make /// # as root: /// make check /// make install /// /// \par Physical Addresses /// /// The functions bcm2845_peri_read(), bcm2845_peri_write() and bcm2845_peri_set_bits() /// are low level peripheral register access functions. They are designed to use /// physical addresses as described in section 1.2.3 ARM physical addresses /// of the BCM2835 ARM Peripherals manual. /// Physical addresses range from 0x20000000 to 0x20FFFFFF for peripherals. The bus /// addresses for peripherals are set up to map onto the peripheral bus address range starting at /// 0x7E000000. Thus a peripheral advertised in the manual at bus address 0x7Ennnnnn is available at /// physical address 0x20nnnnnn. /// /// \par Pin Numbering /// /// The GPIO pin numbering as used by RPi is different to and inconsistent with the underlying /// BCM 2835 chip pin numbering. http://elinux.org/RPi_BCM2835_GPIOs /// /// RPi has a 26 pin IDE header that provides access to some of the GPIO pins on the BCM 2835, /// as well as power and ground pins. Not all GPIO pins on the BCM 2835 are available on the /// IDE header. /// /// The functions in this library are designed to be passed the BCM 2835 GPIO pin number and _not_ /// the RPi pin number. There are symbolic definitions for each of the available pins /// that you should use for convenience. See \ref RPiGPIOPin. /// /// \par SPI Pins /// /// The bcm2835_spi_* functions allow you to control the BCM 2835 SPI0 interface, /// allowing you to send and received data by SPI (Serial Peripheral Interface). /// For more information about SPI, see http://en.wikipedia.org/wiki/Serial_Peripheral_Interface_Bus /// /// When bcm2835_spi_begin() is called it changes the behaviour of the SPI interface pins from their /// default GPIO behaviour in order to support SPI. While SPI is in use, you will not be able /// to control the state of the SPI pins through the usual bcm2835_spi_gpio_write(). /// When bcm2835_spi_end() is called, the SPI pins will all revert to inputs, and can then be /// configured and controlled with the usual bcm2835_gpio_* calls. /// /// The Raspberry Pi GPIO pins used for SPI are: /// /// - P1-19 (MOSI) /// - P1-21 (MISO) /// - P1-23 (CLK) /// - P1-24 (CE0) /// - P1-26 (CE1) /// /// \par Open Source Licensing GPL V2 /// /// This is the appropriate option if you want to share the source code of your /// application with everyone you distribute it to, and you also want to give them /// the right to share who uses it. If you wish to use this software under Open /// Source Licensing, you must contribute all your source code to the open source /// community in accordance with the GPL Version 2 when your application is /// distributed. See http://www.gnu.org/copyleft/gpl.html and COPYING /// /// \par Acknowledgements /// /// Some of this code has been inspired by Dom and Gert. /// /// \par Revision History /// /// \version 1.0 Initial release /// \version 1.1 Minor bug fixes /// \version 1.2 Added support for SPI /// \version 1.3 Added bcm2835_spi_transfern() /// \version 1.4 Fixed a problem that prevented SPI CE1 being used. Reported by David Robinson. /// \version 1.5 Added bcm2835_close() to deinit the library. Suggested by C?sar Ortiz /// \version 1.6 Document testing on 2012-07-15-wheezy-raspbian and Occidentalisv01 /// Functions bcm2835_gpio_ren(), bcm2835_gpio_fen(), bcm2835_gpio_hen() /// bcm2835_gpio_len(), bcm2835_gpio_aren() and bcm2835_gpio_afen() now /// changes only the pin specified. Other pins that were already previously /// enabled stay enabled. /// Added bcm2835_gpio_clr_ren(), bcm2835_gpio_clr_fen(), bcm2835_gpio_clr_hen() /// bcm2835_gpio_clr_len(), bcm2835_gpio_clr_aren(), bcm2835_gpio_clr_afen() /// to clear the enable for individual pins, suggested by Andreas Sundstrom. /// \version 1.7 Added bcm2835_spi_transfernb to support different buffers for read and write. /// \version 1.8 Improvements to read barrier, as suggested by maddin. /// \version 1.9 Improvements contributed by mikew: /// I noticed that it was mallocing memory for the mmaps on /dev/mem. /// It's not necessary to do that, you can just mmap the file directly, /// so I've removed the mallocs (and frees). /// I've also modified delayMicroseconds() to use nanosleep() for long waits, /// and a busy wait on a high resolution timer for the rest. This is because /// I've found that calling nanosleep() takes at least 100-200 us. /// You need to link using '-lrt' using this version. /// I've added some unsigned casts to the debug prints to silence compiler /// warnings I was getting, fixed some typos, and changed the value of /// BCM2835_PAD_HYSTERESIS_ENABLED to 0x08 as per Gert van Loo's doc at /// http://www.scribd.com/doc/101830961/GPIO-Pads-Control2 /// Also added a define for the passwrd value that Gert says is needed to /// change pad control settings. /// \version 1.10 Changed the names of the delay functions to bcm2835_delay() /// and bcm2835_delayMicroseconds() to prevent collisions with wiringPi. /// Macros to map delay()-> bcm2835_delay() and /// Macros to map delayMicroseconds()-> bcm2835_delayMicroseconds(), which /// can be disabled by defining BCM2835_NO_DELAY_COMPATIBILITY /// \version 1.11 Fixed incorrect link to download file /// \version 1.12 New GPIO pin definitions for RPi version 2 (which has a different GPIO mapping) /// /// \author Mike McCauley (mikem@open.com.au) // Defines for BCM2835 #ifndef BCM2835_H #define BCM2835_H #include /// \defgroup constants Constants for passing to and from library functions /// The values here are designed to be passed to various functions in the bcm2835 library. /// @{ /// This means pin HIGH, true, 3.3volts on a pin. #define HIGH 0x1 /// This means pin LOW, false, 0volts on a pin. #define LOW 0x0 // Physical addresses for various peripheral register sets /// Base Physical Address of the BCM 2835 peripheral registers #define BCM2835_PERI_BASE 0x20000000 /// Base Physical Address of the Pads registers #define BCM2835_GPIO_PADS (BCM2835_PERI_BASE + 0x100000) /// Base Physical Address of the Clock/timer registers #define BCM2835_CLOCK_BASE (BCM2835_PERI_BASE + 0x101000) /// Base Physical Address of the GPIO registers #define BCM2835_GPIO_BASE (BCM2835_PERI_BASE + 0x200000) /// Base Physical Address of the SPI0 registers #define BCM2835_SPI0_BASE (BCM2835_PERI_BASE + 0x204000) /// Base Physical Address of the PWM registers #define BCM2835_GPIO_PWM (BCM2835_PERI_BASE + 0x20C000) /// Size of memory page on RPi #define BCM2835_PAGE_SIZE (4*1024) /// Size of memory block on RPi #define BCM2835_BLOCK_SIZE (4*1024) // Defines for GPIO // The BCM2835 has 54 GPIO pins. // BCM2835 data sheet, Page 90 onwards. /// GPIO register offsets from BCM2835_GPIO_BASE. Offsets into the GPIO Peripheral block in bytes per 6.1 Register View #define BCM2835_GPFSEL0 0x0000 ///< GPIO Function Select 0 #define BCM2835_GPFSEL1 0x0004 ///< GPIO Function Select 1 #define BCM2835_GPFSEL2 0x0008 ///< GPIO Function Select 2 #define BCM2835_GPFSEL3 0x000c ///< GPIO Function Select 3 #define BCM2835_GPFSEL4 0x0010 ///< GPIO Function Select 4 #define BCM2835_GPFSEL5 0x0014 ///< GPIO Function Select 5 #define BCM2835_GPSET0 0x001c ///< GPIO Pin Output Set 0 #define BCM2835_GPSET1 0x0020 ///< GPIO Pin Output Set 1 #define BCM2835_GPCLR0 0x0028 ///< GPIO Pin Output Clear 0 #define BCM2835_GPCLR1 0x002c ///< GPIO Pin Output Clear 1 #define BCM2835_GPLEV0 0x0034 ///< GPIO Pin Level 0 #define BCM2835_GPLEV1 0x0038 ///< GPIO Pin Level 1 #define BCM2835_GPEDS0 0x0040 ///< GPIO Pin Event Detect Status 0 #define BCM2835_GPEDS1 0x0044 ///< GPIO Pin Event Detect Status 1 #define BCM2835_GPREN0 0x004c ///< GPIO Pin Rising Edge Detect Enable 0 #define BCM2835_GPREN1 0x0050 ///< GPIO Pin Rising Edge Detect Enable 1 #define BCM2835_GPFEN0 0x0048 ///< GPIO Pin Falling Edge Detect Enable 0 #define BCM2835_GPFEN1 0x005c ///< GPIO Pin Falling Edge Detect Enable 1 #define BCM2835_GPHEN0 0x0064 ///< GPIO Pin High Detect Enable 0 #define BCM2835_GPHEN1 0x0068 ///< GPIO Pin High Detect Enable 1 #define BCM2835_GPLEN0 0x0070 ///< GPIO Pin Low Detect Enable 0 #define BCM2835_GPLEN1 0x0074 ///< GPIO Pin Low Detect Enable 1 #define BCM2835_GPAREN0 0x007c ///< GPIO Pin Async. Rising Edge Detect 0 #define BCM2835_GPAREN1 0x0080 ///< GPIO Pin Async. Rising Edge Detect 1 #define BCM2835_GPAFEN0 0x0088 ///< GPIO Pin Async. Falling Edge Detect 0 #define BCM2835_GPAFEN1 0x008c ///< GPIO Pin Async. Falling Edge Detect 1 #define BCM2835_GPPUD 0x0094 ///< GPIO Pin Pull-up/down Enable #define BCM2835_GPPUDCLK0 0x0098 ///< GPIO Pin Pull-up/down Enable Clock 0 #define BCM2835_GPPUDCLK1 0x009c ///< GPIO Pin Pull-up/down Enable Clock 1 /// \brief bcm2835PortFunction /// Port function select modes for bcm2845_gpio_fsel() typedef enum { BCM2835_GPIO_FSEL_INPT = 0b000, ///< Input BCM2835_GPIO_FSEL_OUTP = 0b001, ///< Output BCM2835_GPIO_FSEL_ALT0 = 0b100, ///< Alternate function 0 BCM2835_GPIO_FSEL_ALT1 = 0b101, ///< Alternate function 1 BCM2835_GPIO_FSEL_ALT2 = 0b110, ///< Alternate function 2 BCM2835_GPIO_FSEL_ALT3 = 0b111, ///< Alternate function 3 BCM2835_GPIO_FSEL_ALT4 = 0b011, ///< Alternate function 4 BCM2835_GPIO_FSEL_ALT5 = 0b010, ///< Alternate function 5 BCM2835_GPIO_FSEL_MASK = 0b111 ///< Function select bits mask } bcm2835FunctionSelect; /// \brief bcm2835PUDControl /// Pullup/Pulldown defines for bcm2845_gpio_pud() typedef enum { BCM2835_GPIO_PUD_OFF = 0b00, ///< Off ? disable pull-up/down BCM2835_GPIO_PUD_DOWN = 0b01, ///< Enable Pull Down control BCM2835_GPIO_PUD_UP = 0b10 ///< Enable Pull Up control } bcm2835PUDControl; /// Pad control register offsets from BCM2835_GPIO_PADS #define BCM2835_PADS_GPIO_0_27 0x002c ///< Pad control register for pads 0 to 27 #define BCM2835_PADS_GPIO_28_45 0x0030 ///< Pad control register for pads 28 to 45 #define BCM2835_PADS_GPIO_46_53 0x0034 ///< Pad control register for pads 46 to 53 /// Pad Control masks #define BCM2835_PAD_PASSWRD (0x5A << 24) ///< Password to enable setting pad mask #define BCM2835_PAD_SLEW_RATE_UNLIMITED 0x10 ///< Slew rate unlimited #define BCM2835_PAD_HYSTERESIS_ENABLED 0x08 ///< Hysteresis enabled #define BCM2835_PAD_DRIVE_2mA 0x00 ///< 2mA drive current #define BCM2835_PAD_DRIVE_4mA 0x01 ///< 4mA drive current #define BCM2835_PAD_DRIVE_6mA 0x02 ///< 6mA drive current #define BCM2835_PAD_DRIVE_8mA 0x03 ///< 8mA drive current #define BCM2835_PAD_DRIVE_10mA 0x04 ///< 10mA drive current #define BCM2835_PAD_DRIVE_12mA 0x05 ///< 12mA drive current #define BCM2835_PAD_DRIVE_14mA 0x06 ///< 14mA drive current #define BCM2835_PAD_DRIVE_16mA 0x07 ///< 16mA drive current /// \brief bcm2835PadGroup /// Pad group specification for bcm2845_gpio_pad() typedef enum { BCM2835_PAD_GROUP_GPIO_0_27 = 0, ///< Pad group for GPIO pads 0 to 27 BCM2835_PAD_GROUP_GPIO_28_45 = 1, ///< Pad group for GPIO pads 28 to 45 BCM2835_PAD_GROUP_GPIO_46_53 = 2 ///< Pad group for GPIO pads 46 to 53 } bcm2835PadGroup; /// \brief RPiGPIOPin /// Here we define Raspberry Pin GPIO pins on P1 in terms of the underlying BCM GPIO pin numbers. /// These can be passed as a pin number to any function requiring a pin. /// Not all pins on the RPi 26 bin IDE plug are connected to GPIO pins /// and some can adopt an alternate function. /// RPi version 2 has some slightly different pinouts, and these are values RPI_V2_*. /// At bootup, pins 8 and 10 are set to UART0_TXD, UART0_RXD (ie the alt0 function) respectively /// When SPI0 is in use (ie after bcm2835_spi_begin()), pins 19, 21, 23, 24, 26 are dedicated to SPI /// and can't be controlled independently typedef enum { RPI_GPIO_P1_03 = 0, ///< Version 1, Pin P1-03 RPI_GPIO_P1_05 = 1, ///< Version 1, Pin P1-05 RPI_GPIO_P1_07 = 4, ///< Version 1, Pin P1-07 RPI_GPIO_P1_08 = 14, ///< Version 1, Pin P1-08, defaults to alt function 0 UART0_TXD RPI_GPIO_P1_10 = 15, ///< Version 1, Pin P1-10, defaults to alt function 0 UART0_RXD RPI_GPIO_P1_11 = 17, ///< Version 1, Pin P1-11 RPI_GPIO_P1_12 = 18, ///< Version 1, Pin P1-12 RPI_GPIO_P1_13 = 21, ///< Version 1, Pin P1-13 RPI_GPIO_P1_15 = 22, ///< Version 1, Pin P1-15 RPI_GPIO_P1_16 = 23, ///< Version 1, Pin P1-16 RPI_GPIO_P1_18 = 24, ///< Version 1, Pin P1-18 RPI_GPIO_P1_19 = 10, ///< Version 1, Pin P1-19, MOSI when SPI0 in use RPI_GPIO_P1_21 = 9, ///< Version 1, Pin P1-21, MISO when SPI0 in use RPI_GPIO_P1_22 = 25, ///< Version 1, Pin P1-22 RPI_GPIO_P1_23 = 11, ///< Version 1, Pin P1-23, CLK when SPI0 in use RPI_GPIO_P1_24 = 8, ///< Version 1, Pin P1-24, CE0 when SPI0 in use RPI_GPIO_P1_26 = 7, ///< Version 1, Pin P1-26, CE1 when SPI0 in use // RPi Version 2 RPI_V2_GPIO_P1_03 = 2, ///< Version 2, Pin P1-03 RPI_V2_GPIO_P1_05 = 3, ///< Version 2, Pin P1-05 RPI_V2_GPIO_P1_07 = 4, ///< Version 2, Pin P1-07 RPI_V2_GPIO_P1_08 = 14, ///< Version 2, Pin P1-08, defaults to alt function 0 UART0_TXD RPI_V2_GPIO_P1_10 = 15, ///< Version 2, Pin P1-10, defaults to alt function 0 UART0_RXD RPI_V2_GPIO_P1_11 = 17, ///< Version 2, Pin P1-11 RPI_V2_GPIO_P1_12 = 18, ///< Version 2, Pin P1-12 RPI_V2_GPIO_P1_13 = 27, ///< Version 2, Pin P1-13 RPI_V2_GPIO_P1_15 = 22, ///< Version 2, Pin P1-15 RPI_V2_GPIO_P1_16 = 23, ///< Version 2, Pin P1-16 RPI_V2_GPIO_P1_18 = 24, ///< Version 2, Pin P1-18 RPI_V2_GPIO_P1_19 = 10, ///< Version 2, Pin P1-19, MOSI when SPI0 in use RPI_V2_GPIO_P1_21 = 9, ///< Version 2, Pin P1-21, MISO when SPI0 in use RPI_V2_GPIO_P1_22 = 25, ///< Version 2, Pin P1-22 RPI_V2_GPIO_P1_23 = 11, ///< Version 2, Pin P1-23, CLK when SPI0 in use RPI_V2_GPIO_P1_24 = 8, ///< Version 2, Pin P1-24, CE0 when SPI0 in use RPI_V2_GPIO_P1_26 = 7 ///< Version 2, Pin P1-26, CE1 when SPI0 in use } RPiGPIOPin; /// Defines for SPI /// GPIO register offsets from BCM2835_SPI0_BASE. /// Offsets into the SPI Peripheral block in bytes per 10.5 SPI Register Map #define BCM2835_SPI0_CS 0x0000 ///< SPI Master Control and Status #define BCM2835_SPI0_FIFO 0x0004 ///< SPI Master TX and RX FIFOs #define BCM2835_SPI0_CLK 0x0008 ///< SPI Master Clock Divider #define BCM2835_SPI0_DLEN 0x000c ///< SPI Master Data Length #define BCM2835_SPI0_LTOH 0x0010 ///< SPI LOSSI mode TOH #define BCM2835_SPI0_DC 0x0014 ///< SPI DMA DREQ Controls // Register masks for SPI0_CS #define BCM2835_SPI0_CS_LEN_LONG 0x02000000 ///< Enable Long data word in Lossi mode if DMA_LEN is set #define BCM2835_SPI0_CS_DMA_LEN 0x01000000 ///< Enable DMA mode in Lossi mode #define BCM2835_SPI0_CS_CSPOL2 0x00800000 ///< Chip Select 2 Polarity #define BCM2835_SPI0_CS_CSPOL1 0x00400000 ///< Chip Select 1 Polarity #define BCM2835_SPI0_CS_CSPOL0 0x00200000 ///< Chip Select 0 Polarity #define BCM2835_SPI0_CS_RXF 0x00100000 ///< RXF - RX FIFO Full #define BCM2835_SPI0_CS_RXR 0x00080000 ///< RXR RX FIFO needs Reading ( full) #define BCM2835_SPI0_CS_TXD 0x00040000 ///< TXD TX FIFO can accept Data #define BCM2835_SPI0_CS_RXD 0x00020000 ///< RXD RX FIFO contains Data #define BCM2835_SPI0_CS_DONE 0x00010000 ///< Done transfer Done #define BCM2835_SPI0_CS_TE_EN 0x00008000 ///< Unused #define BCM2835_SPI0_CS_LMONO 0x00004000 ///< Unused #define BCM2835_SPI0_CS_LEN 0x00002000 ///< LEN LoSSI enable #define BCM2835_SPI0_CS_REN 0x00001000 ///< REN Read Enable #define BCM2835_SPI0_CS_ADCS 0x00000800 ///< ADCS Automatically Deassert Chip Select #define BCM2835_SPI0_CS_INTR 0x00000400 ///< INTR Interrupt on RXR #define BCM2835_SPI0_CS_INTD 0x00000200 ///< INTD Interrupt on Done #define BCM2835_SPI0_CS_DMAEN 0x00000100 ///< DMAEN DMA Enable #define BCM2835_SPI0_CS_TA 0x00000080 ///< Transfer Active #define BCM2835_SPI0_CS_CSPOL 0x00000040 ///< Chip Select Polarity #define BCM2835_SPI0_CS_CLEAR 0x00000030 ///< Clear FIFO Clear RX and TX #define BCM2835_SPI0_CS_CLEAR_RX 0x00000020 ///< Clear FIFO Clear RX #define BCM2835_SPI0_CS_CLEAR_TX 0x00000010 ///< Clear FIFO Clear TX #define BCM2835_SPI0_CS_CPOL 0x00000008 ///< Clock Polarity #define BCM2835_SPI0_CS_CPHA 0x00000004 ///< Clock Phase #define BCM2835_SPI0_CS_CS 0x00000003 ///< Chip Select /// \brief bcm2835SPIBitOrder /// Specifies the SPI data bit ordering typedef enum { BCM2835_SPI_BIT_ORDER_LSBFIRST = 0, ///< LSB First BCM2835_SPI_BIT_ORDER_MSBFIRST = 1 ///< MSB First }bcm2835SPIBitOrder; /// \brief bcm2835SPIMode /// Specify the SPI data mode typedef enum { BCM2835_SPI_MODE0 = 0, ///< CPOL = 0, CPHA = 0 BCM2835_SPI_MODE1 = 1, ///< CPOL = 0, CPHA = 1 BCM2835_SPI_MODE2 = 2, ///< CPOL = 1, CPHA = 0 BCM2835_SPI_MODE3 = 3, ///< CPOL = 1, CPHA = 1 }bcm2835SPIMode; /// \brief bcm2835SPIChipSelect /// Specify the SPI chip select pin(s) typedef enum { BCM2835_SPI_CS0 = 0, ///< Chip Select 0 BCM2835_SPI_CS1 = 1, ///< Chip Select 1 BCM2835_SPI_CS2 = 2, ///< Chip Select 2 (ie pins CS1 and CS2 are asserted) BCM2835_SPI_CS_NONE = 3, ///< No CS, control it yourself } bcm2835SPIChipSelect; /// \brief bcm2835SPIClockDivider /// Specifies the divider used to generate the SPI clock from the system clock. /// Figures below give the divider, clock period and clock frequency. typedef enum { BCM2835_SPI_CLOCK_DIVIDER_65536 = 0, ///< 65536 = 256us = 4kHz BCM2835_SPI_CLOCK_DIVIDER_32768 = 32768, ///< 32768 = 126us = 8kHz BCM2835_SPI_CLOCK_DIVIDER_16384 = 16384, ///< 16384 = 64us = 15.625kHz BCM2835_SPI_CLOCK_DIVIDER_8192 = 8192, ///< 8192 = 32us = 31.25kHz BCM2835_SPI_CLOCK_DIVIDER_4096 = 4096, ///< 4096 = 16us = 62.5kHz BCM2835_SPI_CLOCK_DIVIDER_2048 = 2048, ///< 2048 = 8us = 125kHz BCM2835_SPI_CLOCK_DIVIDER_1024 = 1024, ///< 1024 = 4us = 250kHz BCM2835_SPI_CLOCK_DIVIDER_512 = 512, ///< 512 = 2us = 500kHz BCM2835_SPI_CLOCK_DIVIDER_256 = 256, ///< 256 = 1us = 1MHz BCM2835_SPI_CLOCK_DIVIDER_128 = 128, ///< 128 = 500ns = = 2MHz BCM2835_SPI_CLOCK_DIVIDER_64 = 64, ///< 64 = 250ns = 4MHz BCM2835_SPI_CLOCK_DIVIDER_32 = 32, ///< 32 = 125ns = 8MHz BCM2835_SPI_CLOCK_DIVIDER_16 = 16, ///< 16 = 50ns = 20MHz BCM2835_SPI_CLOCK_DIVIDER_8 = 8, ///< 8 = 25ns = 40MHz BCM2835_SPI_CLOCK_DIVIDER_4 = 4, ///< 4 = 12.5ns 80MHz BCM2835_SPI_CLOCK_DIVIDER_2 = 2, ///< 2 = 6.25ns = 160MHz BCM2835_SPI_CLOCK_DIVIDER_1 = 1, ///< 0 = 256us = 4kHz } bcm2835SPIClockDivider; /// @} // Defines for PWM #define BCM2835_PWM_CONTROL 0 #define BCM2835_PWM_STATUS 1 #define BCM2835_PWM0_RANGE 4 #define BCM2835_PWM0_DATA 5 #define BCM2835_PWM1_RANGE 8 #define BCM2835_PWM1_DATA 9 #define BCM2835_PWMCLK_CNTL 40 #define BCM2835_PWMCLK_DIV 41 #define BCM2835_PWM1_MS_MODE 0x8000 /// Run in MS mode #define BCM2835_PWM1_USEFIFO 0x2000 /// Data from FIFO #define BCM2835_PWM1_REVPOLAR 0x1000 /// Reverse polarity #define BCM2835_PWM1_OFFSTATE 0x0800 /// Output Off state #define BCM2835_PWM1_REPEATFF 0x0400 /// Repeat last value if FIFO empty #define BCM2835_PWM1_SERIAL 0x0200 /// Run in serial mode #define BCM2835_PWM1_ENABLE 0x0100 /// Channel Enable #define BCM2835_PWM0_MS_MODE 0x0080 /// Run in MS mode #define BCM2835_PWM0_USEFIFO 0x0020 /// Data from FIFO #define BCM2835_PWM0_REVPOLAR 0x0010 /// Reverse polarity #define BCM2835_PWM0_OFFSTATE 0x0008 /// Output Off state #define BCM2835_PWM0_REPEATFF 0x0004 /// Repeat last value if FIFO empty #define BCM2835_PWM0_SERIAL 0x0002 /// Run in serial mode #define BCM2835_PWM0_ENABLE 0x0001 /// Channel Enable // Historical name compatibility #ifndef BCM2835_NO_DELAY_COMPATIBILITY #define delay(x) bcm2835_delay(x) #define delayMicroseconds(x) bcm2835_delayMicroseconds(x) #endif #if defined(BCM2835_FUNCS) #ifdef __cplusplus extern "C" { #endif /// \defgroup init Library initialisation and management /// These functions allow you to initialise and control the bcm2835 library /// @{ /// Initialise the library by opening /dev/mem and getting pointers to the /// internal memory for BCM 2835 device registers. You must call this (successfully) /// before calling any other /// functions in this library (except bcm2835_set_debug). /// If bcm2835_init() fails by returning 0, /// calling any other function may result in crashes or other failures. /// Prints messages to stderr in case of errors. /// \return 1 if successful else 0 extern int bcm2835_init(void); /// Close the library, deallocating any allocated memory and closing /dev/mem /// \return 1 if successful else 0 extern int bcm2835_close(void); /// Sets the debug level of the library. /// A value of 1 prevents mapping to /dev/mem, and makes the library print out /// what it would do, rather than accessing the GPIO registers. /// A value of 0, the default, causes normal operation. /// Call this before calling bcm2835_init(); /// \param[in] debug The new debug level. 1 means debug extern void bcm2835_set_debug(uint8_t debug); /// @} // end of init /// \defgroup lowlevel Low level register access /// These functions provide low level register access, and should not generally /// need to be used /// /// @{ /// Reads 32 bit value from a peripheral address /// The read is done twice, and is therefore always safe in terms of /// manual section 1.3 Peripheral access precautions for correct memory ordering /// \param[in] paddr Physical address to read from. See BCM2835_GPIO_BASE etc. /// \return the value read from the 32 bit register /// \sa Physical Addresses extern uint32_t bcm2835_peri_read(volatile uint32_t* paddr); /// Reads 32 bit value from a peripheral address without the read barrier /// You should only use this when your code has previously called bcm2835_peri_read() /// within the same peripheral, and no other peripheral access has occurred since. /// \param[in] paddr Physical address to read from. See BCM2835_GPIO_BASE etc. /// \return the value read from the 32 bit register /// \sa Physical Addresses extern uint32_t bcm2835_peri_read_nb(volatile uint32_t* paddr); /// Writes 32 bit value from a peripheral address /// The write is done twice, and is therefore always safe in terms of /// manual section 1.3 Peripheral access precautions for correct memory ordering /// \param[in] paddr Physical address to read from. See BCM2835_GPIO_BASE etc. /// \param[in] value The 32 bit value to write /// \sa Physical Addresses extern void bcm2835_peri_write(volatile uint32_t* paddr, uint32_t value); /// Writes 32 bit value from a peripheral address without the write barrier /// You should only use this when your code has previously called bcm2835_peri_write() /// within the same peripheral, and no other peripheral access has occurred since. /// \param[in] paddr Physical address to read from. See BCM2835_GPIO_BASE etc. /// \param[in] value The 32 bit value to write /// \sa Physical Addresses extern void bcm2835_peri_write_nb(volatile uint32_t* paddr, uint32_t value); /// Alters a number of bits in a 32 peripheral register. /// It reads the current value and then alters the bits defined as 1 in mask, /// according to the bit value in value. /// All other bits that are 0 in the mask are unaffected. /// Use this to alter a subset of the bits in a register. /// The write is done twice, and is therefore always safe in terms of /// manual section 1.3 Peripheral access precautions for correct memory ordering /// \param[in] paddr Physical address to read from. See BCM2835_GPIO_BASE etc. /// \param[in] value The 32 bit value to write, masked in by mask. /// \param[in] mask Bitmask that defines the bits that will be altered in the register. /// \sa Physical Addresses extern void bcm2835_peri_set_bits(volatile uint32_t* paddr, uint32_t value, uint32_t mask); /// @} // end of lowlevel /// \defgroup gpio GPIO register access /// These functions allow you to control the GPIO interface. You can set the /// function of each GPIO pin, read the input state and set the output state. /// @{ /// Sets the Function Select register for the given pin, which configures /// the pin as Input, Output or one of the 6 alternate functions. /// \param[in] pin GPIO number, or one of RPI_GPIO_P1_* from RPiGPIOPin. /// \param[in] mode Mode to set the pin to, one of BCM2835_GPIO_FSEL_* from \ref bcm2835FunctionSelect extern void bcm2835_gpio_fsel(uint8_t pin, uint8_t mode); /// Sets the specified pin output to /// HIGH. /// \param[in] pin GPIO number, or one of RPI_GPIO_P1_* from \ref RPiGPIOPin. /// \sa bcm2835_gpio_write() extern void bcm2835_gpio_set(uint8_t pin); /// Sets the specified pin output to /// LOW. /// \param[in] pin GPIO number, or one of RPI_GPIO_P1_* from \ref RPiGPIOPin. /// \sa bcm2835_gpio_write() extern void bcm2835_gpio_clr(uint8_t pin); /// Reads the current level on the specified /// pin and returns either HIGH or LOW. Works whether or not the pin /// is an input or an output. /// \param[in] pin GPIO number, or one of RPI_GPIO_P1_* from \ref RPiGPIOPin. /// \return the current level either HIGH or LOW extern uint8_t bcm2835_gpio_lev(uint8_t pin); /// Event Detect Status. /// Tests whether the specified pin has detected a level or edge /// as requested by bcm2835_gpio_ren(), bcm2835_gpio_fen(), bcm2835_gpio_hen(), /// bcm2835_gpio_len(), bcm2835_gpio_aren(), bcm2835_gpio_afen(). /// Clear the flag for a given pin by calling bcm2835_gpio_set_eds(pin); /// \param[in] pin GPIO number, or one of RPI_GPIO_P1_* from \ref RPiGPIOPin. /// \return HIGH if the event detect status for th given pin is true. extern uint8_t bcm2835_gpio_eds(uint8_t pin); /// Sets the Event Detect Status register for a given pin to 1, /// which has the effect of clearing the flag. Use this after seeing /// an Event Detect Status on the pin. /// \param[in] pin GPIO number, or one of RPI_GPIO_P1_* from \ref RPiGPIOPin. extern void bcm2835_gpio_set_eds(uint8_t pin); /// Enable Rising Edge Detect Enable for the specified pin. /// When a rising edge is detected, sets the appropriate pin in Event Detect Status. /// The GPRENn registers use /// synchronous edge detection. This means the input signal is sampled using the /// system clock and then it is looking for a ?011? pattern on the sampled signal. This /// has the effect of suppressing glitches. /// \param[in] pin GPIO number, or one of RPI_GPIO_P1_* from \ref RPiGPIOPin. extern void bcm2835_gpio_ren(uint8_t pin); /// Disable Rising Edge Detect Enable for the specified pin. /// \param[in] pin GPIO number, or one of RPI_GPIO_P1_* from \ref RPiGPIOPin. extern void bcm2835_gpio_clr_ren(uint8_t pin); /// Enable Falling Edge Detect Enable for the specified pin. /// When a falling edge is detected, sets the appropriate pin in Event Detect Status. /// The GPRENn registers use /// synchronous edge detection. This means the input signal is sampled using the /// system clock and then it is looking for a ?100? pattern on the sampled signal. This /// has the effect of suppressing glitches. /// \param[in] pin GPIO number, or one of RPI_GPIO_P1_* from \ref RPiGPIOPin. extern void bcm2835_gpio_fen(uint8_t pin); /// Disable Falling Edge Detect Enable for the specified pin. /// \param[in] pin GPIO number, or one of RPI_GPIO_P1_* from \ref RPiGPIOPin. extern void bcm2835_gpio_clr_fen(uint8_t pin); /// Enable High Detect Enable for the specified pin. /// When a HIGH level is detected on the pin, sets the appropriate pin in Event Detect Status. /// \param[in] pin GPIO number, or one of RPI_GPIO_P1_* from \ref RPiGPIOPin. extern void bcm2835_gpio_hen(uint8_t pin); /// Disable High Detect Enable for the specified pin. /// \param[in] pin GPIO number, or one of RPI_GPIO_P1_* from \ref RPiGPIOPin. extern void bcm2835_gpio_clr_hen(uint8_t pin); /// Enable Low Detect Enable for the specified pin. /// When a LOW level is detected on the pin, sets the appropriate pin in Event Detect Status. /// \param[in] pin GPIO number, or one of RPI_GPIO_P1_* from \ref RPiGPIOPin. extern void bcm2835_gpio_len(uint8_t pin); /// Disable Low Detect Enable for the specified pin. /// \param[in] pin GPIO number, or one of RPI_GPIO_P1_* from \ref RPiGPIOPin. extern void bcm2835_gpio_clr_len(uint8_t pin); /// Enable Asynchronous Rising Edge Detect Enable for the specified pin. /// When a rising edge is detected, sets the appropriate pin in Event Detect Status. /// Asynchronous means the incoming signal is not sampled by the system clock. As such /// rising edges of very short duration can be detected. /// \param[in] pin GPIO number, or one of RPI_GPIO_P1_* from \ref RPiGPIOPin. extern void bcm2835_gpio_aren(uint8_t pin); /// Disable Asynchronous Rising Edge Detect Enable for the specified pin. /// \param[in] pin GPIO number, or one of RPI_GPIO_P1_* from \ref RPiGPIOPin. extern void bcm2835_gpio_clr_aren(uint8_t pin); /// Enable Asynchronous Falling Edge Detect Enable for the specified pin. /// When a falling edge is detected, sets the appropriate pin in Event Detect Status. /// Asynchronous means the incoming signal is not sampled by the system clock. As such /// falling edges of very short duration can be detected. /// \param[in] pin GPIO number, or one of RPI_GPIO_P1_* from \ref RPiGPIOPin. extern void bcm2835_gpio_afen(uint8_t pin); /// Disable Asynchronous Falling Edge Detect Enable for the specified pin. /// \param[in] pin GPIO number, or one of RPI_GPIO_P1_* from \ref RPiGPIOPin. extern void bcm2835_gpio_clr_afen(uint8_t pin); /// Sets the Pull-up/down register for the given pin. This is /// used with bcm2835_gpio_pudclk() to set the Pull-up/down resistor for the given pin. /// However, it is usually more convenient to use bcm2835_gpio_set_pud(). /// \param[in] pud The desired Pull-up/down mode. One of BCM2835_GPIO_PUD_* from bcm2835PUDControl /// \sa bcm2835_gpio_set_pud() extern void bcm2835_gpio_pud(uint8_t pud); /// Clocks the Pull-up/down value set earlier by bcm2835_gpio_pud() into the pin. /// \param[in] pin GPIO number, or one of RPI_GPIO_P1_* from \ref RPiGPIOPin. /// \param[in] on HIGH to clock the value from bcm2835_gpio_pud() into the pin. /// LOW to remove the clock. /// \sa bcm2835_gpio_set_pud() extern void bcm2835_gpio_pudclk(uint8_t pin, uint8_t on); /// Reads and returns the Pad Control for the given GPIO group. /// \param[in] group The GPIO pad group number, one of BCM2835_PAD_GROUP_GPIO_* /// \return Mask of bits from BCM2835_PAD_* from \ref bcm2835PadGroup extern uint32_t bcm2835_gpio_pad(uint8_t group); /// Sets the Pad Control for the given GPIO group. /// \param[in] group The GPIO pad group number, one of BCM2835_PAD_GROUP_GPIO_* /// \param[in] control Mask of bits from BCM2835_PAD_* from \ref bcm2835PadGroup extern void bcm2835_gpio_set_pad(uint8_t group, uint32_t control); /// Delays for the specified number of milliseconds. /// Uses nanosleep(), and therefore does not use CPU until the time is up. /// \param[in] millis Delay in milliseconds extern void bcm2835_delay (unsigned int millis); /// Delays for the specified number of microseconds. /// Uses nanosleep(), and therefore does not use CPU until the time is up. /// However, you are at the mercy of nanosleep(). From the manual for nanosleep: /// If the interval specified in req is not an exact multiple of the granularity /// underlying clock (see time(7)), then the interval will be /// rounded up to the next multiple. Furthermore, after the sleep com- /// pletes, there may still be a delay before the CPU becomes free to once /// again execute the calling thread. /// For times less than about 450 microseconds, uses a busy wait on a high resolution timer. /// It is reported that a delay of 0 microseconds on RaspberryPi will in fact /// result in a dleay of about 80 microseconds. Your mileage may vary. /// \param[in] micros Delay in microseconds extern void bcm2835_delayMicroseconds (unsigned int micros); /// Sets the output state of the specified pin /// \param[in] pin GPIO number, or one of RPI_GPIO_P1_* from \ref RPiGPIOPin. /// \param[in] on HIGH sets the output to HIGH and LOW to LOW. extern void bcm2835_gpio_write(uint8_t pin, uint8_t on); /// Sets the Pull-up/down mode for the specified pin. This is more convenient than /// clocking the mode in with bcm2835_gpio_pud() and bcm2835_gpio_pudclk(). /// \param[in] pin GPIO number, or one of RPI_GPIO_P1_* from \ref RPiGPIOPin. /// \param[in] pud The desired Pull-up/down mode. One of BCM2835_GPIO_PUD_* from bcm2835PUDControl extern void bcm2835_gpio_set_pud(uint8_t pin, uint8_t pud); /// @} /// \defgroup spi SPI access /// These functions let you use SPI0 (Serial Peripheral Interface) to /// interface with an external SPI device. /// @{ /// Start SPI operations. /// Forces RPi SPI0 pins P1-19 (MOSI), P1-21 (MISO), P1-23 (CLK), P1-24 (CE0) and P1-26 (CE1) /// to alternate function ALT0, which enables those pins for SPI interface. /// You should call bcm2835_spi_end() when all SPI functions are complete to return the pins to /// their default functions /// \sa bcm2835_spi_end() extern void bcm2835_spi_begin(void); /// End SPI operations. /// SPI0 pins P1-19 (MOSI), P1-21 (MISO), P1-23 (CLK), P1-24 (CE0) and P1-26 (CE1) /// are returned to their default INPUT behaviour. extern void bcm2835_spi_end(void); /// Sets the SPI bit order /// NOTE: has no effect. Not supported by SPI0. /// Defaults to /// \param[in] order The desired bit order, one of BCM2835_SPI_BIT_ORDER_*, /// see \ref bcm2835SPIBitOrder extern void bcm2835_spi_setBitOrder(uint8_t order); /// Sets the SPI clock divider and therefore the /// SPI clock speed. /// \param[in] divider The desired SPI clock divider, one of BCM2835_SPI_CLOCK_DIVIDER_*, /// see \ref bcm2835SPIClockDivider extern void bcm2835_spi_setClockDivider(uint16_t divider); /// Sets the SPI data mode /// Sets the clock polarity and phase /// \param[in] mode The desired data mode, one of BCM2835_SPI_MODE*, /// see \ref bcm2835SPIMode extern void bcm2835_spi_setDataMode(uint8_t mode); /// Sets the chip select pin(s) /// When an bcm2835_spi_transfer() is made, the selected pin(s) will be asserted during the /// transfer. /// \param[in] cs Specifies the CS pins(s) that are used to activate the desired slave. /// One of BCM2835_SPI_CS*, see \ref bcm2835SPIChipSelect extern void bcm2835_spi_chipSelect(uint8_t cs); /// Sets the chip select pin polarity for a given pin /// When an bcm2835_spi_transfer() occurs, the currently selected chip select pin(s) /// will be asserted to the /// value given by active. When transfers are not happening, the chip select pin(s) /// return to the complement (inactive) value. /// \param[in] cs The chip select pin to affect /// \param[in] active Whether the chip select pin is to be active HIGH extern void bcm2835_spi_setChipSelectPolarity(uint8_t cs, uint8_t active); /// Transfers one byte to and from the currently selected SPI slave. /// Asserts the currently selected CS pins (as previously set by bcm2835_spi_chipSelect) /// during the transfer. /// Clocks the 8 bit value out on MOSI, and simultaneously clocks in data from MISO. /// Returns the read data byte from the slave. /// Uses polled transfer as per section 10.6.1 of the BCM 2835 ARM Peripherls manual /// \param[in] value The 8 bit data byte to write to MOSI /// \return The 8 bit byte simultaneously read from MISO /// \sa bcm2835_spi_transfern() extern uint8_t bcm2835_spi_transfer(uint8_t value); /// Transfers any number of bytes to and from the currently selected SPI slave. /// Asserts the currently selected CS pins (as previously set by bcm2835_spi_chipSelect) /// during the transfer. /// Clocks the len 8 bit bytes out on MOSI, and simultaneously clocks in data from MISO. /// The data read read from the slave is placed into rbuf. rbuf must be at least len bytes long /// Uses polled transfer as per section 10.6.1 of the BCM 2835 ARM Peripherls manual /// \param[in] tbuf Buffer of bytes to send. /// \param[out] rbuf Received bytes will by put in this buffer /// \param[in] len Number of bytes in the tbuf buffer, and the number of bytes to send/received /// \sa bcm2835_spi_transfer() extern void bcm2835_spi_transfernb(char* tbuf, char* rbuf, uint32_t len); /// Transfers any number of bytes to and from the currently selected SPI slave /// using bcm2835_spi_transfernb. /// The returned data from the slave replaces the transmitted data in the buffer. /// \param[in,out] buf Buffer of bytes to send. Received bytes will replace the contents /// \param[in] len Number of bytes int eh buffer, and the number of bytes to send/received /// \sa bcm2835_spi_transfer() extern void bcm2835_spi_transfern(char* buf, uint32_t len); /// @} #ifdef __cplusplus } #endif #endif // DECLS #endif // BCM2835_H /// @example blink.c /// Blinks RPi GPIO pin 11 on and off /// @example input.c /// Reads the state of an RPi input pin /// @example event.c /// Shows how to use event detection on an input pin /// @example spi.c /// Shows how to use SPI interface to transfer a byte to and from an SPI device /// @example spin.c /// Shows how to use SPI interface to transfer a number of bytes to and from an SPI device