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Diff: OneWire.cpp
- Revision:
- 10:c89b9ad6097c
- Parent:
- 9:4af0015b0f47
- Child:
- 11:bc8ed7280966
--- a/OneWire.cpp Sat Jan 26 21:21:27 2019 +0000
+++ b/OneWire.cpp Sun Jan 27 14:11:28 2019 +0000
@@ -115,23 +115,11 @@
*/
#include "OneWire.h"
-#if defined(TARGET_STM)
- #define MODE() mode(OpenDrain)
- #define INPUT() (*gpio.reg_set = gpio.mask) // write 1 to open drain
- #define OUTPUT() // configured as output in the constructor and stays output forever
- #define READ() ((*gpio.reg_in & gpio.mask) ? 1 : 0)
- #define WRITE(x) write(x)
-#else
- #define MODE() mode(PullUp)
- #define INPUT() input()
- #define OUTPUT() output()
- #define READ() read()
- #define WRITE(x) write(x)
-#endif
-
/**
- * @brief
- * @note
+ * @brief Constructs a OneWire object.
+ * @note GPIO is configured as output and an internal pull up resistor is connected.
+ * But because for STM chips it takes very long time to change from output
+ * to input an open drain mode is used rather and the GPIO remains output forever.
* @param
* @retval
*/
@@ -140,20 +128,19 @@
{
timer.stop();
timer.reset();
- output(); // configure as output
- MODE(); // set mode PullUp/OpenDrain
+ MODE(); // set mode either PullUp or OpenDrain
#if ONEWIRE_SEARCH
reset_search();
#endif
}
-// Perform the onewire reset function. We will wait up to 250uS for
-// the bus to come high, if it doesn't then it is broken or shorted
-// and we return a 0;
-//
-// Returns 1 if a device asserted a presence pulse, 0 otherwise.
-
-//
+/**
+ * @brief Performs the onewire reset function.
+ * @note We will wait up to 250uS for the bus to come high,
+ * if it doesn't then it is broken or shorted and we return a 0;
+ * @param
+ * @retval 1 if a device asserted a presence pulse, 0 otherwise.
+ */
uint8_t OneWire::reset(void)
{
uint8_t r;
@@ -177,11 +164,12 @@
return r;
}
-//
-// Write a bit. Port and bit is used to cut lookup time and provide
-// more certain timing.
-
-//
+/**
+ * @brief Writes a bit.
+ * @note GPIO registers are used for STM chips to cut time.
+ * @param
+ * @retval
+ */
void OneWire::write_bit(uint8_t v)
{
OUTPUT();
@@ -199,24 +187,24 @@
}
}
-//
-// Read a bit. Port and bit is used to cut lookup time and provide
-// more certain timing.
-
-//
+/**
+ * @brief Reads a bit.
+ * @note GPIO registers are used for STM chips to cut time.
+ * @param
+ * @retval
+ */
uint8_t OneWire::read_bit(void)
{
uint8_t r;
int t;
OUTPUT();
+ timer.start();
WRITE(0);
- timer.start();
INPUT();
t = timer.read_us();
if (t < 7)
wait_us(7 - t);
- timer.reset();
r = READ();
timer.stop();
timer.reset();
@@ -224,14 +212,16 @@
return r;
}
-//
-// Write a byte. The writing code uses the active drivers to raise the
-// pin high, if you need power after the write (e.g. DS18S20 in
-// parasite power mode) then set 'power' to 1, otherwise the pin will
-// go tri-state at the end of the write to avoid heating in a short or
-// other mishap.
-
-//
+/**
+ * @brief Writes a byte.
+ * @note The writing code uses the active drivers to raise the
+ pin high, if you need power after the write (e.g. DS18S20 in
+ parasite power mode) then set 'power' to 1, otherwise the pin will
+ go tri-state at the end of the write to avoid heating in a short or
+ other mishap.
+ * @param
+ * @retval
+ */
void OneWire::write_byte(uint8_t v, uint8_t power /* = 0 */ )
{
uint8_t bitMask;
@@ -243,7 +233,7 @@
}
/**
- * @brief
+ * @brief Writes bytes.
* @note
* @param
* @retval
@@ -256,10 +246,12 @@
INPUT();
}
-//
-// Read a byte
-
-//
+/**
+ * @brief Reads a byte.
+ * @note
+ * @param
+ * @retval
+ */
uint8_t OneWire::read_byte()
{
uint8_t bitMask;
@@ -274,7 +266,7 @@
}
/**
- * @brief
+ * @brief Reads bytes.
* @note
* @param
* @retval
@@ -285,30 +277,34 @@
buf[i] = read_byte();
}
-//
-// Do a ROM select
-
-//
+/**
+ * @brief Selects ROM.
+ * @note
+ * @param
+ * @retval
+ */
void OneWire::select(const uint8_t rom[8])
{
uint8_t i;
- write_byte(0x55); // Choose ROM
+ write_byte(0x55); // Choose ROM
for (i = 0; i < 8; i++)
write_byte(rom[i]);
}
-//
-// Do a ROM skip
-
-//
+/**
+ * @brief Skips ROM select.
+ * @note
+ * @param
+ * @retval
+ */
void OneWire::skip()
{
- write_byte(0xCC); // Skip ROM
+ write_byte(0xCC); // Skip ROM
}
/**
- * @brief
+ * @brief Unpowers the chip.
* @note
* @param
* @retval
@@ -321,10 +317,13 @@
#if ONEWIRE_SEARCH
//
-// You need to use this function to start a search again from the beginning.
-// You do not need to do it for the first search, though you could.
-
-//
+/**
+ * @brief Resets the search state.
+ * @note We need to use this function to start a search again from the beginning.
+ * We do not need to do it for the first search, though we could.
+ * @param
+ * @retval
+ */
void OneWire::reset_search()
{
// reset the search state
@@ -338,10 +337,12 @@
}
}
-// Setup the search to find the device type 'family_code' on the next call
-// to search(*newAddr) if it is present.
-
-//
+/**
+ * @brief Sets the search state to find SearchFamily type devices.
+ * @note
+ * @param
+ * @retval
+ */
void OneWire::target_search(uint8_t family_code)
{
// set the search state to find SearchFamily type devices
@@ -353,23 +354,24 @@
LastDeviceFlag = false;
}
-//
-// Perform a search. If this function returns a '1' then it has
-// enumerated the next device and you may retrieve the ROM from the
-// OneWire::address variable. If there are no devices, no further
-// devices, or something horrible happens in the middle of the
-// enumeration then a 0 is returned. If a new device is found then
-// its address is copied to newAddr. Use OneWire::reset_search() to
-// start over.
-//
-// --- Replaced by the one from the Dallas Semiconductor web site ---
-//--------------------------------------------------------------------------
-// Perform the 1-Wire Search Algorithm on the 1-Wire bus using the existing
-// search state.
-// Return true : device found, ROM number in ROM_NO buffer
-// false : device not found, end of search
-
-//
+/**
+ * @brief Performs a search.
+ * @note Perform a search. If this function returns a '1' then it has
+ enumerated the next device and you may retrieve the ROM from the
+ OneWire::address variable. If there are no devices, no further
+ devices, or something horrible happens in the middle of the
+ enumeration then a 0 is returned. If a new device is found then
+ its address is copied to newAddr. Use OneWire::reset_search() to
+ start over.
+
+ --- Replaced by the one from the Dallas Semiconductor web site ---
+ -------------------------------------------------------------------------
+ Perform the 1-Wire Search Algorithm on the 1-Wire bus using the existing
+ search state.
+ * @param
+ * @retval true : device found, ROM number in ROM_NO buffer
+ * false : device not found, end of search
+ */
uint8_t OneWire::search(uint8_t* newAddr)
{
uint8_t id_bit_number;
@@ -480,13 +482,16 @@
return search_result;
}
#endif
+//
#if ONEWIRE_CRC
-// The 1-Wire CRC scheme is described in Maxim Application Note 27:
-
-// "Understanding and Using Cyclic Redundancy Checks with Maxim iButton Products"
-// Compute a Dallas Semiconductor 8 bit CRC directly.
-
//
+/**
+ * @brief Computes a Dallas Semiconductor 8 bit CRC directly.
+ * @note The 1-Wire CRC scheme is described in Maxim Application Note 27:
+ "Understanding and Using Cyclic Redundancy Checks with Maxim iButton Products"
+ * @param
+ * @retval
+ */
uint8_t OneWire::crc8(const uint8_t* addr, uint8_t len)
{
uint8_t crc = 0;
@@ -505,6 +510,3 @@
return crc;
}
#endif
-
-
-