diff options
Diffstat (limited to 'src/drivers/ms5611/ms5611_i2c.cpp')
| -rw-r--r-- | src/drivers/ms5611/ms5611_i2c.cpp | 278 |
1 files changed, 278 insertions, 0 deletions
diff --git a/src/drivers/ms5611/ms5611_i2c.cpp b/src/drivers/ms5611/ms5611_i2c.cpp new file mode 100644 index 000000000..87d9b94a6 --- /dev/null +++ b/src/drivers/ms5611/ms5611_i2c.cpp @@ -0,0 +1,278 @@ +/**************************************************************************** + * + * Copyright (c) 2013 PX4 Development Team. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in + * the documentation and/or other materials provided with the + * distribution. + * 3. Neither the name PX4 nor the names of its contributors may be + * used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS + * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE + * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, + * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS + * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED + * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN + * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + * + ****************************************************************************/ + + /** + * @file ms5611_i2c.cpp + * + * I2C interface for MS5611 + */ + +/* XXX trim includes */ +#include <nuttx/config.h> + +#include <sys/types.h> +#include <stdint.h> +#include <stdbool.h> +#include <assert.h> +#include <debug.h> +#include <errno.h> +#include <unistd.h> + +#include <arch/board/board.h> + +#include <drivers/device/i2c.h> + +#include "ms5611.h" + +#include "board_config.h" + +#ifdef PX4_I2C_OBDEV_MS5611 + +#ifndef PX4_I2C_BUS_ONBOARD + #define MS5611_BUS 1 +#else + #define MS5611_BUS PX4_I2C_BUS_ONBOARD +#endif + +#define MS5611_ADDRESS_1 0x76 /* address select pins pulled high (PX4FMU series v1.6+) */ +#define MS5611_ADDRESS_2 0x77 /* address select pins pulled low (PX4FMU prototypes) */ + + + +device::Device *MS5611_i2c_interface(ms5611::prom_u &prom_buf); + +class MS5611_I2C : public device::I2C +{ +public: + MS5611_I2C(int bus, ms5611::prom_u &prom_buf); + virtual ~MS5611_I2C(); + + virtual int init(); + virtual int read(unsigned offset, void *data, unsigned count); + virtual int ioctl(unsigned operation, unsigned &arg); + +protected: + virtual int probe(); + +private: + ms5611::prom_u &_prom; + + int _probe_address(uint8_t address); + + /** + * Send a reset command to the MS5611. + * + * This is required after any bus reset. + */ + int _reset(); + + /** + * Send a measure command to the MS5611. + * + * @param addr Which address to use for the measure operation. + */ + int _measure(unsigned addr); + + /** + * Read the MS5611 PROM + * + * @return OK if the PROM reads successfully. + */ + int _read_prom(); + +}; + +device::Device * +MS5611_i2c_interface(ms5611::prom_u &prom_buf) +{ + return new MS5611_I2C(MS5611_BUS, prom_buf); +} + +MS5611_I2C::MS5611_I2C(int bus, ms5611::prom_u &prom) : + I2C("MS5611_I2C", nullptr, bus, 0, 400000), + _prom(prom) +{ +} + +MS5611_I2C::~MS5611_I2C() +{ +} + +int +MS5611_I2C::init() +{ + /* this will call probe(), and thereby _probe_address */ + return I2C::init(); +} + +int +MS5611_I2C::read(unsigned offset, void *data, unsigned count) +{ + union _cvt { + uint8_t b[4]; + uint32_t w; + } *cvt = (_cvt *)data; + uint8_t buf[3]; + + /* read the most recent measurement */ + uint8_t cmd = 0; + int ret = transfer(&cmd, 1, &buf[0], 3); + if (ret == OK) { + /* fetch the raw value */ + cvt->b[0] = buf[2]; + cvt->b[1] = buf[1]; + cvt->b[2] = buf[0]; + cvt->b[3] = 0; + } + + return ret; +} + +int +MS5611_I2C::ioctl(unsigned operation, unsigned &arg) +{ + int ret; + + switch (operation) { + case IOCTL_RESET: + ret = _reset(); + break; + + case IOCTL_MEASURE: + ret = _measure(arg); + break; + + default: + ret = EINVAL; + } + + return ret; +} + +int +MS5611_I2C::probe() +{ + _retries = 10; + + if ((OK == _probe_address(MS5611_ADDRESS_1)) || + (OK == _probe_address(MS5611_ADDRESS_2))) { + /* + * Disable retries; we may enable them selectively in some cases, + * but the device gets confused if we retry some of the commands. + */ + _retries = 0; + return OK; + } + + return -EIO; +} + +int +MS5611_I2C::_probe_address(uint8_t address) +{ + /* select the address we are going to try */ + set_address(address); + + /* send reset command */ + if (OK != _reset()) + return -EIO; + + /* read PROM */ + if (OK != _read_prom()) + return -EIO; + + return OK; +} + + +int +MS5611_I2C::_reset() +{ + unsigned old_retrycount = _retries; + uint8_t cmd = ADDR_RESET_CMD; + int result; + + /* bump the retry count */ + _retries = 10; + result = transfer(&cmd, 1, nullptr, 0); + _retries = old_retrycount; + + return result; +} + +int +MS5611_I2C::_measure(unsigned addr) +{ + /* + * Disable retries on this command; we can't know whether failure + * means the device did or did not see the command. + */ + _retries = 0; + + uint8_t cmd = addr; + return transfer(&cmd, 1, nullptr, 0); +} + +int +MS5611_I2C::_read_prom() +{ + uint8_t prom_buf[2]; + union { + uint8_t b[2]; + uint16_t w; + } cvt; + + /* + * Wait for PROM contents to be in the device (2.8 ms) in the case we are + * called immediately after reset. + */ + usleep(3000); + + /* read and convert PROM words */ + for (int i = 0; i < 8; i++) { + uint8_t cmd = ADDR_PROM_SETUP + (i * 2); + + if (OK != transfer(&cmd, 1, &prom_buf[0], 2)) + break; + + /* assemble 16 bit value and convert from big endian (sensor) to little endian (MCU) */ + cvt.b[0] = prom_buf[1]; + cvt.b[1] = prom_buf[0]; + _prom.c[i] = cvt.w; + } + + /* calculate CRC and return success/failure accordingly */ + return ms5611::crc4(&_prom.c[0]) ? OK : -EIO; +} + +#endif /* PX4_I2C_OBDEV_MS5611 */ |