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ds18b20: rewrite C++ to wrap C, add FTI, update examples

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Previously, the C++ and C versions of this driver were separate.  Now
the C++ implementation wraps the C implementation.

In addition, the C++ init() function has been deprecated.  It
currently does nothing, and examples have been modified to remove it's
calls.  This function will be removed in a separate release.

The examples have been further modified to update all detected devices
and print their respective temperatures, instead of only reporting the
on the first device detected.

Signed-off-by: Jon Trulson <jtrulson@ics.com>
This commit is contained in:
Jon Trulson
2017-01-18 13:09:51 -07:00
parent 6769d976a0
commit d3b864362d
15 changed files with 685 additions and 757 deletions
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448
src/ds18b20/ds18b20.c
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@@ -1,6 +1,6 @@
/*
* Author: Jon Trulson <jtrulson@ics.com>
* Copyright (c) 2016 Intel Corporation.
* Copyright (c) 2016-2017 Intel Corporation.
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
@@ -23,24 +23,15 @@
*/
#include <assert.h>
#include <upm_utilities.h>
#include "ds18b20.h"
// I'd rather use MRAA_UART_OW_ROMCODE_SIZE defined in uart_ow.h, but
// this then can't be used to specify array sizes since it's a static
// const int, rather than a define. This should be fixed in MRAA (PR
// submitted 9/2016). Until then, work around it.
#if !defined(MRAA_UART_OW_ROMCODE)
# define ROMCODE_SIZE 8
#else
# define ROMCODE_SIZE MRAA_UART_OW_ROMCODE
#endif
// an internal struct we use to store information on the devices
// found during initialization
struct _ds18b20_info_t {
uint8_t id[ROMCODE_SIZE]; // 8-byte romcode id
float temperature;
DS18B20_RESOLUTIONS_T resolution;
uint8_t id[MRAA_UART_OW_ROMCODE_SIZE]; // 8-byte romcode id
float temperature;
DS18B20_RESOLUTIONS_T resolution;
};
// internal utility function forward to read temperature from a single
@@ -49,127 +40,127 @@ static float readSingleTemp(const ds18b20_context dev, unsigned int index);
ds18b20_context ds18b20_init(unsigned int uart)
{
// make sure MRAA is initialized
int mraa_rv;
if ((mraa_rv = mraa_init()) != MRAA_SUCCESS)
{
printf("%s: mraa_init() failed (%d).\n", __FUNCTION__, mraa_rv);
return NULL;
}
ds18b20_context dev =
(ds18b20_context)malloc(sizeof(struct _ds18b20_context));
if (!dev)
return NULL;
// zero out context
memset((void *)dev, 0, sizeof(struct _ds18b20_context));
dev->ow = NULL;
if (!(dev->ow = mraa_uart_ow_init(uart)))
// make sure MRAA is initialized
int mraa_rv;
if ((mraa_rv = mraa_init()) != MRAA_SUCCESS)
{
printf("%s: mraa_uart_ow_init() failed.\n", __FUNCTION__);
ds18b20_close(dev);
return NULL;
printf("%s: mraa_init() failed (%d).\n", __FUNCTION__, mraa_rv);
return NULL;
}
// iterate through the bus and build up a list of detected DS18B20
// devices (only)
ds18b20_context dev =
(ds18b20_context)malloc(sizeof(struct _ds18b20_context));
mraa_result_t rv;
if ((rv = mraa_uart_ow_reset(dev->ow)) != MRAA_SUCCESS)
if (!dev)
return NULL;
// zero out context
memset((void *)dev, 0, sizeof(struct _ds18b20_context));
dev->ow = NULL;
if (!(dev->ow = mraa_uart_ow_init(uart)))
{
printf("%s: mraa_uart_ow_reset() failed, no devices detected\n",
__FUNCTION__);
ds18b20_close(dev);
return NULL;
printf("%s: mraa_uart_ow_init() failed.\n", __FUNCTION__);
ds18b20_close(dev);
return NULL;
}
uint8_t id[ROMCODE_SIZE];
// iterate through the bus and build up a list of detected DS18B20
// devices (only)
rv = mraa_uart_ow_rom_search(dev->ow, 1, id);
if (rv == MRAA_ERROR_UART_OW_NO_DEVICES)
mraa_result_t rv;
if ((rv = mraa_uart_ow_reset(dev->ow)) != MRAA_SUCCESS)
{
// shouldn't happen, but....
printf("%s: mraa_uart_ow_rom_search() failed, no devices detected\n",
__FUNCTION__);
ds18b20_close(dev);
return NULL;
printf("%s: mraa_uart_ow_reset() failed, no devices detected\n",
__FUNCTION__);
ds18b20_close(dev);
return NULL;
}
if (rv == MRAA_ERROR_UART_OW_DATA_ERROR)
uint8_t id[MRAA_UART_OW_ROMCODE_SIZE];
rv = mraa_uart_ow_rom_search(dev->ow, 1, id);
if (rv == MRAA_ERROR_UART_OW_NO_DEVICES)
{
printf("%s: mraa_uart_ow_rom_search() failed, Bus/Data error\n",
__FUNCTION__);
ds18b20_close(dev);
return NULL;
// shouldn't happen, but....
printf("%s: mraa_uart_ow_rom_search() failed, no devices detected\n",
__FUNCTION__);
ds18b20_close(dev);
return NULL;
}
while (rv == MRAA_SUCCESS)
if (rv == MRAA_ERROR_UART_OW_DATA_ERROR)
{
// The first byte (id[0]]) is the device type (family) code. We
// are only interested in the family code for these devices.
printf("%s: mraa_uart_ow_rom_search() failed, Bus/Data error\n",
__FUNCTION__);
ds18b20_close(dev);
return NULL;
}
if ((uint8_t)id[0] == DS18B20_FAMILY_CODE)
while (rv == MRAA_SUCCESS)
{
// The first byte (id[0]]) is the device type (family) code. We
// are only interested in the family code for these devices.
if ((uint8_t)id[0] == DS18B20_FAMILY_CODE)
{
ds18b20_info_t *dsPtr =
(ds18b20_info_t *)realloc((void *)dev->devices,
sizeof(ds18b20_info_t) *
(dev->numDevices + 1));
ds18b20_info_t *dsPtr =
(ds18b20_info_t *)realloc((void *)dev->devices,
sizeof(ds18b20_info_t) *
(dev->numDevices + 1));
if (!dsPtr)
if (!dsPtr)
{
printf("%s: realloc(%zu) failed\n",
__FUNCTION__,
sizeof(ds18b20_info_t) * (dev->numDevices + 1));
ds18b20_close(dev);
return NULL;
printf("%s: realloc(%zu) failed\n",
__FUNCTION__,
sizeof(ds18b20_info_t) * (dev->numDevices + 1));
ds18b20_close(dev);
return NULL;
}
dev->devices = dsPtr;
// copy in the romcode
memcpy(dev->devices[dev->numDevices].id, id,
ROMCODE_SIZE);
// set defaults for now
dev->devices[dev->numDevices].temperature = 0.0;
dev->devices[dev->numDevices].resolution =
DS18B20_RESOLUTION_12BITS;
dev->devices = dsPtr;
// copy in the romcode
memcpy(dev->devices[dev->numDevices].id, id,
MRAA_UART_OW_ROMCODE_SIZE);
// set defaults for now
dev->devices[dev->numDevices].temperature = 0.0;
dev->devices[dev->numDevices].resolution =
DS18B20_RESOLUTION_12BITS;
dev->numDevices++;
dev->numDevices++;
}
// on to the next one
rv = mraa_uart_ow_rom_search(dev->ow, 0, id);
// on to the next one
rv = mraa_uart_ow_rom_search(dev->ow, 0, id);
}
if (!dev->numDevices || !dev->devices)
if (!dev->numDevices || !dev->devices)
{
printf("%s: no DS18B20 devices found on bus\n", __FUNCTION__);
ds18b20_close(dev);
return NULL;
printf("%s: no DS18B20 devices found on bus\n", __FUNCTION__);
ds18b20_close(dev);
return NULL;
}
// iterate through the found devices and query their resolutions
int i;
for (i=0; i<dev->numDevices; i++)
// iterate through the found devices and query their resolutions
int i;
for (i=0; i<dev->numDevices; i++)
{
// read only the first 5 bytes of the scratchpad
static const int numScratch = 5;
uint8_t scratch[numScratch];
// read only the first 5 bytes of the scratchpad
static const int numScratch = 5;
uint8_t scratch[numScratch];
mraa_uart_ow_command(dev->ow, DS18B20_CMD_READ_SCRATCHPAD,
dev->devices[i].id);
mraa_uart_ow_command(dev->ow, DS18B20_CMD_READ_SCRATCHPAD,
dev->devices[i].id);
int j;
for (j=0; j<numScratch; j++)
scratch[j] = (uint8_t)mraa_uart_ow_read_byte(dev->ow);
int j;
for (j=0; j<numScratch; j++)
scratch[j] = (uint8_t)mraa_uart_ow_read_byte(dev->ow);
// config byte, shift the resolution to bit 0
scratch[4] >>= _DS18B20_CFG_RESOLUTION_SHIFT;
// config byte, shift the resolution to bit 0
scratch[4] >>= _DS18B20_CFG_RESOLUTION_SHIFT;
switch (scratch[4] & _DS18B20_CFG_RESOLUTION_MASK)
switch (scratch[4] & _DS18B20_CFG_RESOLUTION_MASK)
{
case 0: dev->devices[i].resolution = DS18B20_RESOLUTION_9BITS; break;
case 1: dev->devices[i].resolution = DS18B20_RESOLUTION_10BITS; break;
@@ -177,228 +168,233 @@ ds18b20_context ds18b20_init(unsigned int uart)
case 3: dev->devices[i].resolution = DS18B20_RESOLUTION_12BITS; break;
}
// reset the bus
mraa_uart_ow_reset(dev->ow);
// reset the bus
mraa_uart_ow_reset(dev->ow);
}
return dev;
return dev;
}
void ds18b20_close(ds18b20_context dev)
{
assert(dev != NULL);
assert(dev != NULL);
if (dev->devices)
free(dev->devices);
if (dev->ow)
mraa_uart_ow_stop(dev->ow);
if (dev->devices)
free(dev->devices);
if (dev->ow)
mraa_uart_ow_stop(dev->ow);
free(dev);
free(dev);
}
void ds18b20_update(const ds18b20_context dev, int index)
{
assert(dev != NULL);
assert(dev != NULL);
if (index >= dev->numDevices)
if (index >= dev->numDevices)
{
printf("%s: device index %d out of range\n", __FUNCTION__, index);
return;
printf("%s: device index %d out of range\n", __FUNCTION__, index);
return;
}
// should we update all of them?
bool doAll = (index < 0) ? true : false;
// should we update all of them?
bool doAll = (index < 0) ? true : false;
if (doAll)
if (doAll)
{
// if we want to update all of them, we will first send the
// convert command to all of them, then wait. This will be
// faster, timey-wimey wise, then converting, sleeping, and
// reading each individual sensor.
// if we want to update all of them, we will first send the
// convert command to all of them, then wait. This will be
// faster, timey-wimey wise, then converting, sleeping, and
// reading each individual sensor.
int i;
for (i=0; i<dev->numDevices; i++)
mraa_uart_ow_command(dev->ow, DS18B20_CMD_CONVERT, dev->devices[i].id);
int i;
for (i=0; i<dev->numDevices; i++)
mraa_uart_ow_command(dev->ow, DS18B20_CMD_CONVERT, dev->devices[i].id);
}
else
mraa_uart_ow_command(dev->ow, DS18B20_CMD_CONVERT, dev->devices[index].id);
else
mraa_uart_ow_command(dev->ow, DS18B20_CMD_CONVERT, dev->devices[index].id);
// wait for conversion(s) to finish
usleep(750000); // 750ms max
// wait for conversion(s) to finish
upm_delay_ms(750000); // 750ms max
if (doAll)
if (doAll)
{
int i;
for (i=0; i<dev->numDevices; i++)
dev->devices[i].temperature = readSingleTemp(dev, i);
int i;
for (i=0; i<dev->numDevices; i++)
dev->devices[i].temperature = readSingleTemp(dev, i);
}
else
dev->devices[index].temperature = readSingleTemp(dev, index);
else
dev->devices[index].temperature = readSingleTemp(dev, index);
}
// utility function to read temp data from a single sensor
static float readSingleTemp(const ds18b20_context dev, unsigned int index)
{
assert(dev != NULL);
assert(dev != NULL);
if (index >= dev->numDevices)
if (index >= dev->numDevices)
{
printf("%s: device index %d out of range\n", __FUNCTION__, index);
return 0.0;
printf("%s: device index %d out of range\n", __FUNCTION__, index);
return 0.0;
}
static const int numScratch = 9;
uint8_t scratch[numScratch];
static const int numScratch = 9;
uint8_t scratch[numScratch];
// read the 9-byte scratchpad
mraa_uart_ow_command(dev->ow, DS18B20_CMD_READ_SCRATCHPAD,
dev->devices[index].id);
int i;
for (i=0; i<numScratch; i++)
scratch[i] = (uint8_t)mraa_uart_ow_read_byte(dev->ow);
// read the 9-byte scratchpad
mraa_uart_ow_command(dev->ow, DS18B20_CMD_READ_SCRATCHPAD,
dev->devices[index].id);
int i;
for (i=0; i<numScratch; i++)
scratch[i] = (uint8_t)mraa_uart_ow_read_byte(dev->ow);
// validate cksum -- if we get an error, we will warn and simply
// return the current (previously read) temperature
uint8_t crc = mraa_uart_ow_crc8(scratch, 8);
// validate cksum -- if we get an error, we will warn and simply
// return the current (previously read) temperature
uint8_t crc = mraa_uart_ow_crc8(scratch, 8);
if (crc != scratch[8])
if (crc != scratch[8])
{
printf("%s: crc check failed for device %d, returning previously "
"measured temperature\n", __FUNCTION__, index);
return dev->devices[index].temperature;
printf("%s: crc check failed for device %d. Got %02x, expected %02x."
" Returning previously measured temperature\n",
__FUNCTION__, index, scratch[8], crc);
return dev->devices[index].temperature;
}
// check the sign bit(s)
bool negative = (scratch[1] & 0x80) ? true : false;
// check the sign bit(s)
bool negative = (scratch[1] & 0x80) ? true : false;
// shift everything into position
int16_t temp = (scratch[1] << 8) | scratch[0];
// shift everything into position
int16_t temp = (scratch[1] << 8) | scratch[0];
// grab the fractional
uint8_t frac = temp & 0x0f;
// grab the fractional
uint8_t frac = temp & 0x0f;
// depending on the resolution, some frac bits should be ignored, so
// we mask them off. For 12bits, all bits are valid so we leve them
// alone.
// depending on the resolution, some frac bits should be ignored, so
// we mask them off. For 12bits, all bits are valid so we leve them
// alone.
switch (dev->devices[index].resolution)
switch (dev->devices[index].resolution)
{
case DS18B20_RESOLUTION_9BITS: frac &= 0x08; break;
case DS18B20_RESOLUTION_10BITS: frac &= 0x0c; break;
case DS18B20_RESOLUTION_11BITS: frac &= 0x0e; break;
// use all bits for 12b
// use all bits for 12b
case DS18B20_RESOLUTION_12BITS: break;
default:
printf("%s: Internal error, invalid resolution %d\n",
__FUNCTION__, (int)dev->devices[index].resolution);
break;
}
// remove the fractional with extreme prejudice
temp >>= 4;
// remove the fractional with extreme prejudice
temp >>= 4;
// compensate for sign
if (negative)
temp -= 65536; // 2^^16
// compensate for sign
if (negative)
temp -= 65536; // 2^^16
// convert
return ( (float)temp + ((float)frac * 0.0625) );
// convert
return ( (float)temp + ((float)frac * 0.0625) );
}
float ds18b20_get_temperature(const ds18b20_context dev, unsigned int index)
{
assert(dev != NULL);
assert(dev != NULL);
if (index >= dev->numDevices)
if (index >= dev->numDevices)
{
printf("%s: device index %d out of range\n", __FUNCTION__, index);
return 0.0;
printf("%s: device index %d out of range\n", __FUNCTION__, index);
return 0.0;
}
return dev->devices[index].temperature;
return dev->devices[index].temperature;
}
void ds18b20_set_resolution(const ds18b20_context dev, unsigned int index,
DS18B20_RESOLUTIONS_T res)
{
assert(dev != NULL);
assert(dev != NULL);
if (index >= dev->numDevices)
if (index >= dev->numDevices)
{
printf("%s: device index %d out of range\n", __FUNCTION__, index);
return;
printf("%s: device index %d out of range\n", __FUNCTION__, index);
return;
}
static const int numScratch = 9;
uint8_t scratch[numScratch];
static const int numScratch = 9;
uint8_t scratch[numScratch];
// read the 9-byte scratchpad
mraa_uart_ow_command(dev->ow, DS18B20_CMD_READ_SCRATCHPAD,
dev->devices[index].id);
int i;
for (i=0; i<numScratch; i++)
scratch[i] = (uint8_t)mraa_uart_ow_read_byte(dev->ow);
// read the 9-byte scratchpad
mraa_uart_ow_command(dev->ow, DS18B20_CMD_READ_SCRATCHPAD,
dev->devices[index].id);
int i;
for (i=0; i<numScratch; i++)
scratch[i] = (uint8_t)mraa_uart_ow_read_byte(dev->ow);
// resolution is stored in byte 4
scratch[4] = ((scratch[4] & ~(_DS18B20_CFG_RESOLUTION_MASK <<
_DS18B20_CFG_RESOLUTION_SHIFT))
| (res << _DS18B20_CFG_RESOLUTION_SHIFT));
// resolution is stored in byte 4
scratch[4] = ((scratch[4] & ~(_DS18B20_CFG_RESOLUTION_MASK <<
_DS18B20_CFG_RESOLUTION_SHIFT))
| (res << _DS18B20_CFG_RESOLUTION_SHIFT));
// now, write back, we only write 3 bytes (2-4), no cksum.
mraa_uart_ow_command(dev->ow, DS18B20_CMD_WRITE_SCRATCHPAD,
dev->devices[index].id);
for (i=0; i<3; i++)
mraa_uart_ow_write_byte(dev->ow, scratch[i+2]);
// now, write back, we only write 3 bytes (2-4), no cksum.
mraa_uart_ow_command(dev->ow, DS18B20_CMD_WRITE_SCRATCHPAD,
dev->devices[index].id);
for (i=0; i<3; i++)
mraa_uart_ow_write_byte(dev->ow, scratch[i+2]);
}
void ds18b20_copy_scratch_pad(const ds18b20_context dev, unsigned int index)
void ds18b20_copy_scratchpad(const ds18b20_context dev, unsigned int index)
{
assert(dev != NULL);
assert(dev != NULL);
if (index >= dev->numDevices)
if (index >= dev->numDevices)
{
printf("%s: device index %d out of range\n", __FUNCTION__, index);
return;
printf("%s: device index %d out of range\n", __FUNCTION__, index);
return;
}
// issue the command
mraa_uart_ow_command(dev->ow, DS18B20_CMD_COPY_SCRATCHPAD,
dev->devices[index].id);
// issue the command
mraa_uart_ow_command(dev->ow, DS18B20_CMD_COPY_SCRATCHPAD,
dev->devices[index].id);
sleep(1); // to be safe...
upm_delay(1); // to be safe...
}
void ds18b20_recallEEPROM(const ds18b20_context dev, unsigned int index)
void ds18b20_recall_eeprom(const ds18b20_context dev, unsigned int index)
{
assert(dev != NULL);
assert(dev != NULL);
if (index >= dev->numDevices)
if (index >= dev->numDevices)
{
printf("%s: device index %d out of range\n", __FUNCTION__, index);
return;
printf("%s: device index %d out of range\n", __FUNCTION__, index);
return;
}
// issue the command
mraa_uart_ow_command(dev->ow, DS18B20_CMD_RECALL_EEPROM,
dev->devices[index].id);
// issue the command
mraa_uart_ow_command(dev->ow, DS18B20_CMD_RECALL_EEPROM,
dev->devices[index].id);
// issue read timeslots until a '1' is read back, indicating completion
while (!mraa_uart_ow_bit(dev->ow, 1))
usleep(100);
// issue read timeslots until a '1' is read back, indicating completion
while (!mraa_uart_ow_bit(dev->ow, 1))
upm_delay_us(100);
}
int ds18b20_devices_found(const ds18b20_context dev)
unsigned int ds18b20_devices_found(const ds18b20_context dev)
{
assert(dev != NULL);
assert(dev != NULL);
return dev->numDevices;
return dev->numDevices;
}
const uint8_t *ds18b20_get_id(const ds18b20_context dev, unsigned int index)
{
assert(dev != NULL);
assert(dev != NULL);
if (index >= dev->numDevices)
return NULL;
if (index >= dev->numDevices)
return NULL;
static uint8_t id[ROMCODE_SIZE];
static uint8_t id[MRAA_UART_OW_ROMCODE_SIZE];
memcpy(id, dev->devices[index].id, ROMCODE_SIZE);
return id;
memcpy(id, dev->devices[index].id, MRAA_UART_OW_ROMCODE_SIZE);
return id;
}