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| author | geremy@pubnub.com | 2014-12-28 17:06:19 -0800 |
|---|---|---|
| committer | geremy@pubnub.com | 2014-12-28 17:06:19 -0800 |
| commit | b89bc8cb03f0534805c2112d5fa4253f82ab616f (patch) | |
| tree | 4559202652cbd265fe8a84e4933e36d127b2b465 /python/examples/Adafruit_Python_DHT/source/Raspberry_Pi | |
| parent | c2a3ee12ce2c42b05e1ee31d737d9a8703f4a580 (diff) | |
| download | pubnub-python-b89bc8cb03f0534805c2112d5fa4253f82ab616f.tar.bz2 | |
adding open/close files for door, new humid/temp sensor
Diffstat (limited to 'python/examples/Adafruit_Python_DHT/source/Raspberry_Pi')
4 files changed, 306 insertions, 0 deletions
diff --git a/python/examples/Adafruit_Python_DHT/source/Raspberry_Pi/pi_dht_read.c b/python/examples/Adafruit_Python_DHT/source/Raspberry_Pi/pi_dht_read.c new file mode 100644 index 0000000..0789e60 --- /dev/null +++ b/python/examples/Adafruit_Python_DHT/source/Raspberry_Pi/pi_dht_read.c @@ -0,0 +1,158 @@ +// Copyright (c) 2014 Adafruit Industries +// Author: Tony DiCola + +// Permission is hereby granted, free of charge, to any person obtaining a copy +// of this software and associated documentation files (the "Software"), to deal +// in the Software without restriction, including without limitation the rights +// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell +// copies of the Software, and to permit persons to whom the Software is +// furnished to do so, subject to the following conditions: + +// The above copyright notice and this permission notice shall be included in all +// copies or substantial portions of the Software. + +// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE +// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER +// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, +// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE +// SOFTWARE. +#include <stdbool.h> +#include <stdlib.h> + +#include "pi_dht_read.h" +#include "pi_mmio.h" + +// This is the only processor specific magic value, the maximum amount of time to +// spin in a loop before bailing out and considering the read a timeout. This should +// be a high value, but if you're running on a much faster platform than a Raspberry +// Pi or Beaglebone Black then it might need to be increased. +#define DHT_MAXCOUNT 32000 + +// Number of bit pulses to expect from the DHT. Note that this is 41 because +// the first pulse is a constant 50 microsecond pulse, with 40 pulses to represent +// the data afterwards. +#define DHT_PULSES 41 + +int pi_dht_read(int type, int pin, float* humidity, float* temperature) { + // Validate humidity and temperature arguments and set them to zero. + if (humidity == NULL || temperature == NULL) { + return DHT_ERROR_ARGUMENT; + } + *temperature = 0.0f; + *humidity = 0.0f; + + // Initialize GPIO library. + if (pi_mmio_init() < 0) { + return DHT_ERROR_GPIO; + } + + // Store the count that each DHT bit pulse is low and high. + // Make sure array is initialized to start at zero. + int pulseCounts[DHT_PULSES*2] = {0}; + + // Set pin to output. + pi_mmio_set_output(pin); + + // Bump up process priority and change scheduler to try to try to make process more 'real time'. + set_max_priority(); + + // Set pin high for ~500 milliseconds. + pi_mmio_set_high(pin); + sleep_milliseconds(500); + + // The next calls are timing critical and care should be taken + // to ensure no unnecssary work is done below. + + // Set pin low for ~20 milliseconds. + pi_mmio_set_low(pin); + busy_wait_milliseconds(20); + + // Set pin at input. + pi_mmio_set_input(pin); + // Need a very short delay before reading pins or else value is sometimes still low. + for (volatile int i = 0; i < 50; ++i) { + } + + // Wait for DHT to pull pin low. + uint32_t count = 0; + while (pi_mmio_input(pin)) { + if (++count >= DHT_MAXCOUNT) { + // Timeout waiting for response. + set_default_priority(); + return DHT_ERROR_TIMEOUT; + } + } + + // Record pulse widths for the expected result bits. + for (int i=0; i < DHT_PULSES*2; i+=2) { + // Count how long pin is low and store in pulseCounts[i] + while (!pi_mmio_input(pin)) { + if (++pulseCounts[i] >= DHT_MAXCOUNT) { + // Timeout waiting for response. + set_default_priority(); + return DHT_ERROR_TIMEOUT; + } + } + // Count how long pin is high and store in pulseCounts[i+1] + while (pi_mmio_input(pin)) { + if (++pulseCounts[i+1] >= DHT_MAXCOUNT) { + // Timeout waiting for response. + set_default_priority(); + return DHT_ERROR_TIMEOUT; + } + } + } + + // Done with timing critical code, now interpret the results. + + // Drop back to normal priority. + set_default_priority(); + + // Compute the average low pulse width to use as a 50 microsecond reference threshold. + // Ignore the first two readings because they are a constant 80 microsecond pulse. + uint32_t threshold = 0; + for (int i=2; i < DHT_PULSES*2; i+=2) { + threshold += pulseCounts[i]; + } + threshold /= DHT_PULSES-1; + + // Interpret each high pulse as a 0 or 1 by comparing it to the 50us reference. + // If the count is less than 50us it must be a ~28us 0 pulse, and if it's higher + // then it must be a ~70us 1 pulse. + uint8_t data[5] = {0}; + for (int i=3; i < DHT_PULSES*2; i+=2) { + int index = (i-3)/16; + data[index] <<= 1; + if (pulseCounts[i] >= threshold) { + // One bit for long pulse. + data[index] |= 1; + } + // Else zero bit for short pulse. + } + + // Useful debug info: + //printf("Data: 0x%x 0x%x 0x%x 0x%x 0x%x\n", data[0], data[1], data[2], data[3], data[4]); + + // Verify checksum of received data. + if (data[4] == ((data[0] + data[1] + data[2] + data[3]) & 0xFF)) { + if (type == DHT11) { + // Get humidity and temp for DHT11 sensor. + *humidity = (float)data[0]; + *temperature = (float)data[2]; + } + else if (type == DHT22) { + // Calculate humidity and temp for DHT22 sensor. + *humidity = (data[0] * 256 + data[1]) / 10.0f; + *temperature = ((data[2] & 0x7F) * 256 + data[3]) / 10.0f; + if (data[2] & 0x80) { + *temperature *= -1.0f; + } + } + return DHT_SUCCESS; + } + else { + return DHT_ERROR_CHECKSUM; + } +} diff --git a/python/examples/Adafruit_Python_DHT/source/Raspberry_Pi/pi_dht_read.h b/python/examples/Adafruit_Python_DHT/source/Raspberry_Pi/pi_dht_read.h new file mode 100644 index 0000000..9132e96 --- /dev/null +++ b/python/examples/Adafruit_Python_DHT/source/Raspberry_Pi/pi_dht_read.h @@ -0,0 +1,32 @@ +// Copyright (c) 2014 Adafruit Industries +// Author: Tony DiCola + +// Permission is hereby granted, free of charge, to any person obtaining a copy +// of this software and associated documentation files (the "Software"), to deal +// in the Software without restriction, including without limitation the rights +// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell +// copies of the Software, and to permit persons to whom the Software is +// furnished to do so, subject to the following conditions: + +// The above copyright notice and this permission notice shall be included in all +// copies or substantial portions of the Software. + +// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE +// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER +// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, +// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE +// SOFTWARE. +#ifndef PI_DHT_READ_H +#define PI_DHT_READ_H + +#include "../common_dht_read.h" + +// Read DHT sensor connected to GPIO pin (using BCM numbering). Humidity and temperature will be +// returned in the provided parameters. If a successfull reading could be made a value of 0 +// (DHT_SUCCESS) will be returned. If there was an error reading the sensor a negative value will +// be returned. Some errors can be ignored and retried, specifically DHT_ERROR_TIMEOUT or DHT_ERROR_CHECKSUM. +int pi_dht_read(int sensor, int pin, float* humidity, float* temperature); + +#endif diff --git a/python/examples/Adafruit_Python_DHT/source/Raspberry_Pi/pi_mmio.c b/python/examples/Adafruit_Python_DHT/source/Raspberry_Pi/pi_mmio.c new file mode 100644 index 0000000..6755230 --- /dev/null +++ b/python/examples/Adafruit_Python_DHT/source/Raspberry_Pi/pi_mmio.c @@ -0,0 +1,55 @@ +// Copyright (c) 2014 Adafruit Industries +// Author: Tony DiCola +// Based on code from Gert van Loo & Dom: http://elinux.org/RPi_Low-level_peripherals#GPIO_Code_examples + +// Permission is hereby granted, free of charge, to any person obtaining a copy +// of this software and associated documentation files (the "Software"), to deal +// in the Software without restriction, including without limitation the rights +// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell +// copies of the Software, and to permit persons to whom the Software is +// furnished to do so, subject to the following conditions: + +// The above copyright notice and this permission notice shall be included in all +// copies or substantial portions of the Software. + +// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE +// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER +// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, +// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE +// SOFTWARE. +#include <fcntl.h> +#include <stdlib.h> +#include <string.h> +#include <sys/mman.h> +#include <sys/stat.h> +#include <sys/types.h> +#include <unistd.h> + +#include "pi_mmio.h" + +#define BASE 0x20000000 +#define GPIO_BASE (BASE + 0x200000) +#define GPIO_LENGTH 4096 + +volatile uint32_t* pi_mmio_gpio = NULL; + +int pi_mmio_init(void) { + if (pi_mmio_gpio == NULL) { + int fd = open("/dev/mem", O_RDWR | O_SYNC); + if (fd == -1) { + // Error opening /dev/mem. Probably not running as root. + return MMIO_ERROR_DEVMEM; + } + // Map GPIO memory to location in process space. + pi_mmio_gpio = (uint32_t*)mmap(NULL, GPIO_LENGTH, PROT_READ | PROT_WRITE, MAP_SHARED, fd, GPIO_BASE); + close(fd); + if (pi_mmio_gpio == MAP_FAILED) { + // Don't save the result if the memory mapping failed. + pi_mmio_gpio = NULL; + return MMIO_ERROR_MMAP; + } + } + return MMIO_SUCCESS; +} diff --git a/python/examples/Adafruit_Python_DHT/source/Raspberry_Pi/pi_mmio.h b/python/examples/Adafruit_Python_DHT/source/Raspberry_Pi/pi_mmio.h new file mode 100644 index 0000000..d47a9c3 --- /dev/null +++ b/python/examples/Adafruit_Python_DHT/source/Raspberry_Pi/pi_mmio.h @@ -0,0 +1,61 @@ +// Copyright (c) 2014 Adafruit Industries +// Author: Tony DiCola +// Based on code from Gert van Loo & Dom: http://elinux.org/RPi_Low-level_peripherals#GPIO_Code_examples + +// Permission is hereby granted, free of charge, to any person obtaining a copy +// of this software and associated documentation files (the "Software"), to deal +// in the Software without restriction, including without limitation the rights +// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell +// copies of the Software, and to permit persons to whom the Software is +// furnished to do so, subject to the following conditions: + +// The above copyright notice and this permission notice shall be included in all +// copies or substantial portions of the Software. + +// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE +// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER +// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, +// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE +// SOFTWARE. + +// Simple fast memory-mapped GPIO library for the Raspberry Pi. +#ifndef PI_MMIO_H +#define PI_MMIO_H + +#include <stdint.h> + +#define MMIO_SUCCESS 0 +#define MMIO_ERROR_DEVMEM -1 +#define MMIO_ERROR_MMAP -2 + +volatile uint32_t* pi_mmio_gpio; + +int pi_mmio_init(void); + +static inline void pi_mmio_set_input(const int gpio_number) { + // Set GPIO register to 000 for specified GPIO number. + *(pi_mmio_gpio+((gpio_number)/10)) &= ~(7<<(((gpio_number)%10)*3)); +} + +static inline void pi_mmio_set_output(const int gpio_number) { + // First set to 000 using input function. + pi_mmio_set_input(gpio_number); + // Next set bit 0 to 1 to set output. + *(pi_mmio_gpio+((gpio_number)/10)) |= (1<<(((gpio_number)%10)*3)); +} + +static inline void pi_mmio_set_high(const int gpio_number) { + *(pi_mmio_gpio+7) = 1 << gpio_number; +} + +static inline void pi_mmio_set_low(const int gpio_number) { + *(pi_mmio_gpio+10) = 1 << gpio_number; +} + +static inline uint32_t pi_mmio_input(const int gpio_number) { + return *(pi_mmio_gpio+13) & (1 << gpio_number); +} + +#endif |
