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137 lines
3.3 KiB
C
137 lines
3.3 KiB
C
/*
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* pios_adxl345.c
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* OpenPilotOSX
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*
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* Created by James Cotton on 1/16/11.
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* Copyright 2011 OpenPilot. All rights reserved.
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*
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*/
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#include "pios.h"
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static uint32_t PIOS_SPI_ACCEL;
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/**
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* @brief Claim the SPI bus for the accel communications and select this chip
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*/
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void PIOS_ADXL345_ClaimBus()
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{
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PIOS_SPI_ClaimBus(PIOS_SPI_ACCEL);
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PIOS_ADXL_ENABLE;
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}
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/**
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* @brief Release the SPI bus for the accel communications and end the transaction
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*/
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void PIOS_ADXL345_ReleaseBus()
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{
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PIOS_ADXL_DISABLE;
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PIOS_SPI_ReleaseBus(PIOS_SPI_ACCEL);
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}
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/**
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* @brief Select the sampling rate of the chip
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*
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* This also puts it into high power mode
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*/
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void PIOS_ADXL345_SelectRate(uint8_t rate)
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{
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uint8_t out[2] = {ADXL_RATE_ADDR, rate & 0x0F};
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PIOS_ADXL345_ClaimBus();
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PIOS_SPI_TransferBlock(PIOS_SPI_ACCEL,out,NULL,sizeof(out),NULL);
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PIOS_ADXL345_ReleaseBus();
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}
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/**
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* @brief Set the range of the accelerometer and set the data to be right justified
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* with sign extension. Also keep device in 4 wire mode.
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*/
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void PIOS_ADXL345_SetRange(uint8_t range)
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{
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uint8_t out[2] = {ADXL_FORMAT_ADDR, (range & 0x03) | ADXL_FULL_RES | ADXL_4WIRE};
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PIOS_ADXL345_ClaimBus();
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PIOS_SPI_TransferBlock(PIOS_SPI_ACCEL,out,NULL,sizeof(out),NULL);
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PIOS_ADXL345_ReleaseBus();
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}
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/**
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* @brief Set the fifo depth that triggers an interrupt. This will be matched to the oversampling
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*/
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void PIOS_ADXL345_FifoDepth(uint8_t depth)
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{
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uint8_t out[2] = {ADXL_FIFO_ADDR, (depth & 0x1f) | ADXL_FIFO_STREAM};
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PIOS_ADXL345_ClaimBus();
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PIOS_SPI_TransferBlock(PIOS_SPI_ACCEL,out,NULL,sizeof(out),NULL);
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PIOS_ADXL345_ReleaseBus();
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}
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/**
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* @brief Enable measuring. This also disables the activity sensors (tap or free fall)
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*/
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void PIOS_ADXL345_SetMeasure(uint8_t enable)
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{
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uint8_t out[2] = {ADXL_POWER_ADDR, ADXL_MEAURE};
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PIOS_ADXL345_ClaimBus();
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PIOS_SPI_TransferBlock(PIOS_SPI_ACCEL,out,NULL,sizeof(out),NULL);
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PIOS_ADXL345_ReleaseBus();
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}
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/**
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* @brief Connect to the correct SPI bus
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*/
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void PIOS_ADXL345_Attach(uint32_t spi_id)
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{
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PIOS_SPI_ACCEL = spi_id;
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}
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/**
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* @brief Initialize with good default settings
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*/
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void PIOS_ADXL345_Init()
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{
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PIOS_ADXL345_ReleaseBus();
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PIOS_ADXL345_SelectRate(ADXL_RATE_3200);
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PIOS_ADXL345_SetRange(ADXL_RANGE_8G);
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PIOS_ADXL345_FifoDepth(16);
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PIOS_ADXL345_SetMeasure(1);
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}
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/**
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* @brief Return number of entries in the fifo
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*/
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uint8_t PIOS_ADXL345_FifoElements()
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{
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uint8_t buf[2] = {0,0};
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uint8_t rec[2] = {0,0};
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buf[0] = ADXL_FIFOSTATUS_ADDR | ADXL_READ_BIT ; // Read fifo status
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PIOS_ADXL345_ClaimBus();
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PIOS_SPI_TransferBlock(PIOS_SPI_ACCEL,&buf[0],&rec[0],sizeof(buf),NULL);
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PIOS_ADXL345_ReleaseBus();
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return rec[1] & 0x3f;
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}
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/**
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* @brief Read a single set of values from the x y z channels
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* @returns The number of samples remaining in the fifo
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*/
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uint8_t PIOS_ADXL345_Read(struct pios_adxl345_data * data)
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{
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// To save memory use same buffer for in and out but offset by
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// a byte
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uint8_t buf[9] = {0,0,0,0,0,0,0,0};
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uint8_t rec[9] = {0,0,0,0,0,0,0,0};
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buf[0] = ADXL_X0_ADDR | ADXL_MULTI_BIT | ADXL_READ_BIT ; // Multibyte read starting at X0
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PIOS_ADXL345_ClaimBus();
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PIOS_SPI_TransferBlock(PIOS_SPI_ACCEL,&buf[0],&rec[0],9,NULL);
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PIOS_ADXL345_ReleaseBus();
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data->x = rec[1] + (rec[2] << 8);
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data->y = rec[3] + (rec[4] << 8);
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data->z = rec[5] + (rec[6] << 8);
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return rec[8] & 0x7F; // return number of remaining entries
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}
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