Revision 0:8174d9ceeca1, committed 2013-11-10

Comitter:

arve0

Date:

Sun Nov 10 18:22:27 2013 +0000

Child:

1:659ccb9047ed

Commit message:

Ported from Adafruit's arduino library

Changed in this revision

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Adafruit_ADS1015.cpp	Sun Nov 10 18:22:27 2013 +0000
@@ -0,0 +1,336 @@
+/**************************************************************************/
+/*!
+    @file     Adafruit_ADS1015.cpp
+    @author   K.Townsend (Adafruit Industries)
+    @license  BSD (see LICENSE.txt)
+
+    Ported to mbed by Arve Seljebu - arve0.github.io
+
+    Driver for the ADS1015/ADS1115 ADC
+
+    This is a library for the Adafruit MPL115A2 breakout
+    ----> https://www.adafruit.com/products/1083
+
+    Adafruit invests time and resources providing this open source code,
+    please support Adafruit and open-source hardware by purchasing
+    products from Adafruit!
+
+    @section  HISTORY
+
+    v1.0 - First release
+    v1.1.1 - Ported to mbed
+*/
+/**************************************************************************/
+
+#include <mbed.h>
+#include "Adafruit_ADS1015.h"
+
+/**************************************************************************/
+/*!
+    @brief  Writes 16-bits to the specified destination register
+*/
+/**************************************************************************/
+void Adafruit_ADS1015::writeRegister(uint8_t i2cAddress, uint8_t reg, uint16_t value) {
+  char cmd[3];
+  cmd[0] = (char)reg;
+  cmd[1] = (char)(value>>8);
+  cmd[2] = (char)(value & 0xFF);
+  m_i2c->write(i2cAddress, cmd, 3); 
+}
+
+/**************************************************************************/
+/*!
+    @brief  Reads 16-bits from the specified register
+*/
+/**************************************************************************/
+uint16_t Adafruit_ADS1015::readRegister(uint8_t i2cAddress, uint8_t reg) {
+  char data[2];
+  data[0] = reg; // temporary use this to send address to conversion register
+  m_i2c->write(i2cAddress, data, 1);
+  m_i2c->read(i2cAddress, data, 2);
+  return (data[0] << 8 | data [1]);
+}
+
+/**************************************************************************/
+/*!
+    @brief  Instantiates a new ADS1015 class w/appropriate properties
+*/
+/**************************************************************************/
+Adafruit_ADS1015::Adafruit_ADS1015(I2C* i2c, uint8_t i2cAddress) 
+{
+  // shift 7 bit address 1 left: read expects 8 bit address, see I2C.h
+   m_i2cAddress = i2cAddress << 1;
+   m_conversionDelay = ADS1015_CONVERSIONDELAY;
+   m_bitShift = 4;
+   m_gain = GAIN_TWOTHIRDS; /* +/- 6.144V range (limited to VDD +0.3V max!) */
+   m_i2c = i2c;
+}
+
+/**************************************************************************/
+/*!
+    @brief  Instantiates a new ADS1115 class w/appropriate properties
+*/
+/**************************************************************************/
+Adafruit_ADS1115::Adafruit_ADS1115(I2C* i2c, uint8_t i2cAddress)
+{
+  // shift 7 bit address 1 left: read expects 8 bit address, see mbed's I2C.h
+  m_i2cAddress = i2cAddress << 1;
+  m_conversionDelay = ADS1115_CONVERSIONDELAY;
+  m_bitShift = 0;
+  m_gain = GAIN_TWOTHIRDS; /* +/- 6.144V range (limited to VDD +0.3V max!) */
+  m_i2c = i2c;
+}
+
+/**************************************************************************/
+/*!
+    @brief  Sets the gain and input voltage range
+*/
+/**************************************************************************/
+void Adafruit_ADS1015::setGain(adsGain_t gain)
+{
+  m_gain = gain;
+}
+
+/**************************************************************************/
+/*!
+    @brief  Gets a gain and input voltage range
+*/
+/**************************************************************************/
+adsGain_t Adafruit_ADS1015::getGain()
+{
+  return m_gain;
+}
+
+/**************************************************************************/
+/*!
+    @brief  Gets a single-ended ADC reading from the specified channel
+*/
+/**************************************************************************/
+uint16_t Adafruit_ADS1015::readADC_SingleEnded(uint8_t channel) {
+  if (channel > 3)
+  {
+    return 0;
+  }
+  
+  // Start with default values
+  uint16_t config = ADS1015_REG_CONFIG_CQUE_NONE    | // Disable the comparator (default val)
+                    ADS1015_REG_CONFIG_CLAT_NONLAT  | // Non-latching (default val)
+                    ADS1015_REG_CONFIG_CPOL_ACTVLOW | // Alert/Rdy active low   (default val)
+                    ADS1015_REG_CONFIG_CMODE_TRAD   | // Traditional comparator (default val)
+                    ADS1015_REG_CONFIG_DR_1600SPS   | // 1600 samples per second (default)
+                    ADS1015_REG_CONFIG_MODE_SINGLE;   // Single-shot mode (default)
+
+  // Set PGA/voltage range
+  config |= m_gain;
+
+  // Set single-ended input channel
+  switch (channel)
+  {
+    case (0):
+      config |= ADS1015_REG_CONFIG_MUX_SINGLE_0;
+      break;
+    case (1):
+      config |= ADS1015_REG_CONFIG_MUX_SINGLE_1;
+      break;
+    case (2):
+      config |= ADS1015_REG_CONFIG_MUX_SINGLE_2;
+      break;
+    case (3):
+      config |= ADS1015_REG_CONFIG_MUX_SINGLE_3;
+      break;
+  }
+
+  // Set 'start single-conversion' bit
+  config |= ADS1015_REG_CONFIG_OS_SINGLE;
+
+  // Write config register to the ADC
+  writeRegister(m_i2cAddress, ADS1015_REG_POINTER_CONFIG, config);
+
+  // Wait for the conversion to complete
+  wait_ms(m_conversionDelay);
+
+  // Read the conversion results
+  // Shift 12-bit results right 4 bits for the ADS1015
+  return readRegister(m_i2cAddress, ADS1015_REG_POINTER_CONVERT) >> m_bitShift;  
+}
+
+/**************************************************************************/
+/*! 
+    @brief  Reads the conversion results, measuring the voltage
+            difference between the P (AIN0) and N (AIN1) input.  Generates
+            a signed value since the difference can be either
+            positive or negative.
+*/
+/**************************************************************************/
+int16_t Adafruit_ADS1015::readADC_Differential_0_1() {
+  // Start with default values
+  uint16_t config = ADS1015_REG_CONFIG_CQUE_NONE    | // Disable the comparator (default val)
+                    ADS1015_REG_CONFIG_CLAT_NONLAT  | // Non-latching (default val)
+                    ADS1015_REG_CONFIG_CPOL_ACTVLOW | // Alert/Rdy active low   (default val)
+                    ADS1015_REG_CONFIG_CMODE_TRAD   | // Traditional comparator (default val)
+                    ADS1015_REG_CONFIG_DR_1600SPS   | // 1600 samples per second (default)
+                    ADS1015_REG_CONFIG_MODE_SINGLE;   // Single-shot mode (default)
+
+  // Set PGA/voltage range
+  config |= m_gain;
+                    
+  // Set channels
+  config |= ADS1015_REG_CONFIG_MUX_DIFF_0_1;          // AIN0 = P, AIN1 = N
+
+  // Set 'start single-conversion' bit
+  config |= ADS1015_REG_CONFIG_OS_SINGLE;
+
+  // Write config register to the ADC
+  writeRegister(m_i2cAddress, ADS1015_REG_POINTER_CONFIG, config);
+
+  // Wait for the conversion to complete
+  wait_ms(m_conversionDelay);
+
+  // Read the conversion results
+  uint16_t res = readRegister(m_i2cAddress, ADS1015_REG_POINTER_CONVERT) >> m_bitShift;
+  if (m_bitShift == 0)
+  {
+    return (int16_t)res;
+  }
+  else
+  {
+    // Shift 12-bit results right 4 bits for the ADS1015,
+    // making sure we keep the sign bit intact
+    if (res > 0x07FF)
+    {
+      // negative number - extend the sign to 16th bit
+      res |= 0xF000;
+    }
+    return (int16_t)res;
+  }
+}
+
+/**************************************************************************/
+/*! 
+    @brief  Reads the conversion results, measuring the voltage
+            difference between the P (AIN2) and N (AIN3) input.  Generates
+            a signed value since the difference can be either
+            positive or negative.
+*/
+/**************************************************************************/
+int16_t Adafruit_ADS1015::readADC_Differential_2_3() {
+  // Start with default values
+  uint16_t config = ADS1015_REG_CONFIG_CQUE_NONE    | // Disable the comparator (default val)
+                    ADS1015_REG_CONFIG_CLAT_NONLAT  | // Non-latching (default val)
+                    ADS1015_REG_CONFIG_CPOL_ACTVLOW | // Alert/Rdy active low   (default val)
+                    ADS1015_REG_CONFIG_CMODE_TRAD   | // Traditional comparator (default val)
+                    ADS1015_REG_CONFIG_DR_1600SPS   | // 1600 samples per second (default)
+                    ADS1015_REG_CONFIG_MODE_SINGLE;   // Single-shot mode (default)
+
+  // Set PGA/voltage range
+  config |= m_gain;
+
+  // Set channels
+  config |= ADS1015_REG_CONFIG_MUX_DIFF_2_3;          // AIN2 = P, AIN3 = N
+
+  // Set 'start single-conversion' bit
+  config |= ADS1015_REG_CONFIG_OS_SINGLE;
+
+  // Write config register to the ADC
+  writeRegister(m_i2cAddress, ADS1015_REG_POINTER_CONFIG, config);
+
+  // Wait for the conversion to complete
+  wait_ms(m_conversionDelay);
+
+  // Read the conversion results
+  uint16_t res = readRegister(m_i2cAddress, ADS1015_REG_POINTER_CONVERT) >> m_bitShift;
+  if (m_bitShift == 0)
+  {
+    return (int16_t)res;
+  }
+  else
+  {
+    // Shift 12-bit results right 4 bits for the ADS1015,
+    // making sure we keep the sign bit intact
+    if (res > 0x07FF)
+    {
+      // negative number - extend the sign to 16th bit
+      res |= 0xF000;
+    }
+    return (int16_t)res;
+  }
+}
+
+/**************************************************************************/
+/*!
+    @brief  Sets up the comparator to operate in basic mode, causing the
+            ALERT/RDY pin to assert (go from high to low) when the ADC
+            value exceeds the specified threshold.
+
+            This will also set the ADC in continuous conversion mode.
+*/
+/**************************************************************************/
+void Adafruit_ADS1015::startComparator_SingleEnded(uint8_t channel, int16_t threshold)
+{
+  // Start with default values
+  uint16_t config = ADS1015_REG_CONFIG_CQUE_1CONV   | // Comparator enabled and asserts on 1 match
+                    ADS1015_REG_CONFIG_CLAT_LATCH   | // Latching mode
+                    ADS1015_REG_CONFIG_CPOL_ACTVLOW | // Alert/Rdy active low   (default val)
+                    ADS1015_REG_CONFIG_CMODE_TRAD   | // Traditional comparator (default val)
+                    ADS1015_REG_CONFIG_DR_1600SPS   | // 1600 samples per second (default)
+                    ADS1015_REG_CONFIG_MODE_CONTIN  | // Continuous conversion mode
+                    ADS1015_REG_CONFIG_MODE_CONTIN;   // Continuous conversion mode
+
+  // Set PGA/voltage range
+  config |= m_gain;
+                    
+  // Set single-ended input channel
+  switch (channel)
+  {
+    case (0):
+      config |= ADS1015_REG_CONFIG_MUX_SINGLE_0;
+      break;
+    case (1):
+      config |= ADS1015_REG_CONFIG_MUX_SINGLE_1;
+      break;
+    case (2):
+      config |= ADS1015_REG_CONFIG_MUX_SINGLE_2;
+      break;
+    case (3):
+      config |= ADS1015_REG_CONFIG_MUX_SINGLE_3;
+      break;
+  }
+
+  // Set the high threshold register
+  // Shift 12-bit results left 4 bits for the ADS1015
+  writeRegister(m_i2cAddress, ADS1015_REG_POINTER_HITHRESH, threshold << m_bitShift);
+
+  // Write config register to the ADC
+  writeRegister(m_i2cAddress, ADS1015_REG_POINTER_CONFIG, config);
+}
+
+/**************************************************************************/
+/*!
+    @brief  In order to clear the comparator, we need to read the
+            conversion results.  This function reads the last conversion
+            results without changing the config value.
+*/
+/**************************************************************************/
+int16_t Adafruit_ADS1015::getLastConversionResults()
+{
+  // Wait for the conversion to complete
+  wait_ms(m_conversionDelay);
+
+  // Read the conversion results
+  uint16_t res = readRegister(m_i2cAddress, ADS1015_REG_POINTER_CONVERT) >> m_bitShift;
+  if (m_bitShift == 0)
+  {
+    return (int16_t)res;
+  }
+  else
+  {
+    // Shift 12-bit results right 4 bits for the ADS1015,
+    // making sure we keep the sign bit intact
+    if (res > 0x07FF)
+    {
+      // negative number - extend the sign to 16th bit
+      res |= 0xF000;
+    }
+    return (int16_t)res;
+  }
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Adafruit_ADS1015.h	Sun Nov 10 18:22:27 2013 +0000
@@ -0,0 +1,150 @@
+/**************************************************************************/
+/*!
+    @file       Adafruit_ADS1015.h
+    @author     K. Townsend (Adafruit Industries)
+    @license    BSD (see LICENSE.txt)
+    
+    Ported to mbed by Arve Seljebu - arve0.github.io
+
+    This is a library for the Adafruit ADS1015 breakout board
+    ----> https://www.adafruit.com/products/1083
+
+    Adafruit invests time and resources providing this open source code,
+    please support Adafruit and open-source hardware by purchasing
+    products from Adafruit!
+
+    @section  HISTORY
+
+    v1.0  - First release
+    v1.1  - Added ADS1115 support - W. Earl
+    v1.1.1  - Ported to mbed - Arve Seljebu
+*/
+/**************************************************************************/
+
+#include <mbed.h>
+
+/*=========================================================================
+    I2C ADDRESS/BITS
+    -----------------------------------------------------------------------*/
+    #define ADS1015_ADDRESS                 (0x48)    // 1001 000 (ADDR = GND)
+/*=========================================================================*/
+
+/*=========================================================================
+    CONVERSION DELAY (in mS)
+    -----------------------------------------------------------------------*/
+    #define ADS1015_CONVERSIONDELAY         (1)
+    #define ADS1115_CONVERSIONDELAY         (8)
+/*=========================================================================*/
+
+/*=========================================================================
+    POINTER REGISTER
+    -----------------------------------------------------------------------*/
+    #define ADS1015_REG_POINTER_MASK        (0x03)
+    #define ADS1015_REG_POINTER_CONVERT     (0x00)
+    #define ADS1015_REG_POINTER_CONFIG      (0x01)
+    #define ADS1015_REG_POINTER_LOWTHRESH   (0x02)
+    #define ADS1015_REG_POINTER_HITHRESH    (0x03)
+/*=========================================================================*/
+
+/*=========================================================================
+    CONFIG REGISTER
+    -----------------------------------------------------------------------*/
+    #define ADS1015_REG_CONFIG_OS_MASK      (0x8000)
+    #define ADS1015_REG_CONFIG_OS_SINGLE    (0x8000)  // Write: Set to start a single-conversion
+    #define ADS1015_REG_CONFIG_OS_BUSY      (0x0000)  // Read: Bit = 0 when conversion is in progress
+    #define ADS1015_REG_CONFIG_OS_NOTBUSY   (0x8000)  // Read: Bit = 1 when device is not performing a conversion
+
+    #define ADS1015_REG_CONFIG_MUX_MASK     (0x7000)
+    #define ADS1015_REG_CONFIG_MUX_DIFF_0_1 (0x0000)  // Differential P = AIN0, N = AIN1 (default)
+    #define ADS1015_REG_CONFIG_MUX_DIFF_0_3 (0x1000)  // Differential P = AIN0, N = AIN3
+    #define ADS1015_REG_CONFIG_MUX_DIFF_1_3 (0x2000)  // Differential P = AIN1, N = AIN3
+    #define ADS1015_REG_CONFIG_MUX_DIFF_2_3 (0x3000)  // Differential P = AIN2, N = AIN3
+    #define ADS1015_REG_CONFIG_MUX_SINGLE_0 (0x4000)  // Single-ended AIN0
+    #define ADS1015_REG_CONFIG_MUX_SINGLE_1 (0x5000)  // Single-ended AIN1
+    #define ADS1015_REG_CONFIG_MUX_SINGLE_2 (0x6000)  // Single-ended AIN2
+    #define ADS1015_REG_CONFIG_MUX_SINGLE_3 (0x7000)  // Single-ended AIN3
+
+    #define ADS1015_REG_CONFIG_PGA_MASK     (0x0E00)
+    #define ADS1015_REG_CONFIG_PGA_6_144V   (0x0000)  // +/-6.144V range = Gain 2/3
+    #define ADS1015_REG_CONFIG_PGA_4_096V   (0x0200)  // +/-4.096V range = Gain 1
+    #define ADS1015_REG_CONFIG_PGA_2_048V   (0x0400)  // +/-2.048V range = Gain 2 (default)
+    #define ADS1015_REG_CONFIG_PGA_1_024V   (0x0600)  // +/-1.024V range = Gain 4
+    #define ADS1015_REG_CONFIG_PGA_0_512V   (0x0800)  // +/-0.512V range = Gain 8
+    #define ADS1015_REG_CONFIG_PGA_0_256V   (0x0A00)  // +/-0.256V range = Gain 16
+
+    #define ADS1015_REG_CONFIG_MODE_MASK    (0x0100)
+    #define ADS1015_REG_CONFIG_MODE_CONTIN  (0x0000)  // Continuous conversion mode
+    #define ADS1015_REG_CONFIG_MODE_SINGLE  (0x0100)  // Power-down single-shot mode (default)
+
+    #define ADS1015_REG_CONFIG_DR_MASK      (0x00E0)  
+    #define ADS1015_REG_CONFIG_DR_128SPS    (0x0000)  // 128 samples per second
+    #define ADS1015_REG_CONFIG_DR_250SPS    (0x0020)  // 250 samples per second
+    #define ADS1015_REG_CONFIG_DR_490SPS    (0x0040)  // 490 samples per second
+    #define ADS1015_REG_CONFIG_DR_920SPS    (0x0060)  // 920 samples per second
+    #define ADS1015_REG_CONFIG_DR_1600SPS   (0x0080)  // 1600 samples per second (default)
+    #define ADS1015_REG_CONFIG_DR_2400SPS   (0x00A0)  // 2400 samples per second
+    #define ADS1015_REG_CONFIG_DR_3300SPS   (0x00C0)  // 3300 samples per second
+
+    #define ADS1015_REG_CONFIG_CMODE_MASK   (0x0010)
+    #define ADS1015_REG_CONFIG_CMODE_TRAD   (0x0000)  // Traditional comparator with hysteresis (default)
+    #define ADS1015_REG_CONFIG_CMODE_WINDOW (0x0010)  // Window comparator
+
+    #define ADS1015_REG_CONFIG_CPOL_MASK    (0x0008)
+    #define ADS1015_REG_CONFIG_CPOL_ACTVLOW (0x0000)  // ALERT/RDY pin is low when active (default)
+    #define ADS1015_REG_CONFIG_CPOL_ACTVHI  (0x0008)  // ALERT/RDY pin is high when active
+
+    #define ADS1015_REG_CONFIG_CLAT_MASK    (0x0004)  // Determines if ALERT/RDY pin latches once asserted
+    #define ADS1015_REG_CONFIG_CLAT_NONLAT  (0x0000)  // Non-latching comparator (default)
+    #define ADS1015_REG_CONFIG_CLAT_LATCH   (0x0004)  // Latching comparator
+
+    #define ADS1015_REG_CONFIG_CQUE_MASK    (0x0003)
+    #define ADS1015_REG_CONFIG_CQUE_1CONV   (0x0000)  // Assert ALERT/RDY after one conversions
+    #define ADS1015_REG_CONFIG_CQUE_2CONV   (0x0001)  // Assert ALERT/RDY after two conversions
+    #define ADS1015_REG_CONFIG_CQUE_4CONV   (0x0002)  // Assert ALERT/RDY after four conversions
+    #define ADS1015_REG_CONFIG_CQUE_NONE    (0x0003)  // Disable the comparator and put ALERT/RDY in high state (default)
+/*=========================================================================*/
+
+typedef enum
+{
+  GAIN_TWOTHIRDS    = ADS1015_REG_CONFIG_PGA_6_144V,
+  GAIN_ONE          = ADS1015_REG_CONFIG_PGA_4_096V,
+  GAIN_TWO          = ADS1015_REG_CONFIG_PGA_2_048V,
+  GAIN_FOUR         = ADS1015_REG_CONFIG_PGA_1_024V,
+  GAIN_EIGHT        = ADS1015_REG_CONFIG_PGA_0_512V,
+  GAIN_SIXTEEN      = ADS1015_REG_CONFIG_PGA_0_256V
+} adsGain_t;
+
+class Adafruit_ADS1015
+{
+protected:
+   // Instance-specific properties
+   uint8_t   m_i2cAddress;
+   uint8_t   m_conversionDelay;
+   uint8_t   m_bitShift;
+   adsGain_t m_gain;
+   I2C*      m_i2c;
+   
+
+ public:
+  Adafruit_ADS1015(I2C* i2c = 0, uint8_t i2cAddress = ADS1015_ADDRESS); // set i2c adress = 0 to allow ADS1115 to use this as default constructor
+  uint16_t  readADC_SingleEnded(uint8_t channel);
+  int16_t   readADC_Differential_0_1(void);
+  int16_t   readADC_Differential_2_3(void);
+  void      startComparator_SingleEnded(uint8_t channel, int16_t threshold);
+  int16_t   getLastConversionResults();
+  void      setGain(adsGain_t gain);
+  adsGain_t getGain(void);
+
+ private:
+  uint16_t readRegister(uint8_t i2cAddress, uint8_t reg);
+  void writeRegister(uint8_t i2cAddress, uint8_t reg, uint16_t value);
+};
+
+// Derive from ADS1105 & override construction to set properties
+class Adafruit_ADS1115 : public Adafruit_ADS1015
+{
+ public:
+  Adafruit_ADS1115(I2C* i2c, uint8_t i2cAddress = ADS1015_ADDRESS);
+
+ private:
+};
\ No newline at end of file

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/LICENSE.txt	Sun Nov 10 18:22:27 2013 +0000
@@ -0,0 +1,26 @@
+Software License Agreement (BSD License)
+
+Copyright (c) 2012, Adafruit Industries, Arve Seljebu
+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 of the copyright holders 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 ''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 HOLDER 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.
\ No newline at end of file