Adding device driver for DS2482, 1-Wire Master Bridge

README.md

@@ -3,8 +3,8 @@
 The TWI library is an abstract interface for I2C device drivers. The
 library includes a hardware and software bus manager, and example
 device drivers for I2C Humidity and Temperature Sensor (Si70XX),
-Remote 8-bit I/O expander (PCF8574/PCF8574A), and Digital Pressure
-Sensor (BMP085).
+Remote 8-bit I/O expander (PCF8574/PCF8574A), Digital Pressure
+Sensor (BMP085), and Single/Multi-Channel 1-Wire Master (DS2482).
 
 The software bus manager implementation of the TWI interface uses the
 [Arduino-GPIO](https://github.com/mikaelpatel/Arduino-GPIO)
@@ -20,7 +20,7 @@ Device driver mutex allows a task to complete a device driver function
 in a synchronized manner when using the
 [Arduino-Scheduler](https://github.com/mikaelpatel/Arduino-Scheduler).
 
-Version: 1.8
+Version: 1.9
 
 ## Classes
 
@@ -31,11 +31,13 @@ Version: 1.8
 * [Digital Pressure Sensor, BMP085](./src/Driver/BMP085.h)
 * [Humidity and Temperature Sensor, Si70XX](./src/Driver/Si70XX.h)
 * [Remote 8-bit I/O expander, PCF8574](./src/Driver/PCF8574.h)
+* [Single/Multi-Channel 1-Wire Master, DS2482-100/800](./src/Driver/DS2482.h)
 
 ## Example Sketches
 
 * [Scanner](./examples/Scanner)
 * [BMP085](./examples/BMP085)
+* [DS2482](./examples/DS2482)
 * [PCF8574](./examples/PCF8574)
 * [Si7021](./examples/Si7021)
 

examples/DS2482/DS2482.ino

@@ -0,0 +1,186 @@
+#include "GPIO.h"
+#include "TWI.h"
+#include "Driver/DS2482.h"
+
+// Configure: Software or Hardware TWI
+// #define USE_SOFTWARE_TWI
+#if defined(USE_SOFTWARE_TWI)
+#include "Software/TWI.h"
+#if defined(SAM)
+Software::TWI<BOARD::D8,BOARD::D9> twi;
+#else
+Software::TWI<BOARD::D18,BOARD::D19> twi;
+#endif
+#else
+#include "Hardware/TWI.h"
+Hardware::TWI twi;
+#endif
+
+DS2482 owi(twi);
+
+const size_t ROM_MAX = 8;
+const uint8_t CHARBITS = 8;
+
+// 1-Wire ROM and DS18B20 commands
+enum {
+  SEARCH_ROM = 0xF0,
+  READ_ROM = 0x33,
+  MATCH_ROM = 0x55,
+  SKIP_ROM = 0xCC,
+  ALARM_SEARCH = 0xEC,
+  CONVERT_T = 0x44,
+  READ_SCRATCHPAD = 0xBE
+};
+
+// DS18B20 scratchpad
+struct scratchpad_t {
+  int16_t temperature;
+  int8_t high_trigger;
+  int8_t low_trigger;
+  uint8_t configuration;
+  uint8_t reserved[3];
+  uint8_t crc;
+};
+
+// 1-Wire CRC calculation
+uint8_t one_wire_crc_update(uint8_t crc, uint8_t data)
+{
+  crc = crc ^ data;
+  for (uint8_t i = 0; i < 8; i++) {
+    if (crc & 0x01)
+      crc = (crc >> 1) ^ 0x8C;
+    else
+      crc >>= 1;
+  }
+  return (crc);
+}
+
+// Check assertion to be true, otherwise print line and expression
+#define ASSERT(expr)							\
+  do {									\
+    if (!(expr)) {							\
+      Serial.print(__LINE__);						\
+      Serial.println(F(":assert:" #expr));				\
+      Serial.flush();							\
+      exit(0);								\
+    }									\
+  } while (0)
+
+
+// Print and evaluate expression
+#define TRACE(expr)							\
+  do {									\
+    Serial.print(#expr "=");						\
+    Serial.println(expr);						\
+  } while (0)
+
+
+void setup()
+{
+  Serial.begin(57600);
+  while (!Serial);
+
+  // Reset and configure the TWI 1-Wire Master
+  ASSERT(owi.device_reset());
+  ASSERT(owi.write_configuration());
+
+  // Read and print registers
+  uint8_t config;
+  ASSERT(owi.set_read_pointer(owi.CONFIGURATION_REGISTER, config));
+  TRACE(config);
+
+  uint8_t data;
+  ASSERT(owi.set_read_pointer(owi.READ_DATA_REGISTER, data));
+  TRACE(data);
+
+  uint8_t status;
+  ASSERT(owi.set_read_pointer(owi.STATUS_REGISTER, status));
+  TRACE(status);
+
+#if defined(DS2482_800)
+  uint8_t channel;
+  ASSERT(owi.set_read_pointer(owi.CHANNEL_SELECTION_REGISTER, channel));
+  TRACE(channel);
+#endif
+
+  // Read and print rom from device on 1-Wire bus
+  uint8_t rom[ROM_MAX] = { 0 };
+  uint8_t crc = 0;
+  ASSERT(owi.one_wire_reset());
+  ASSERT(owi.one_wire_write_byte(READ_ROM));
+  Serial.print(F("read_rom="));
+  for (size_t i = 0; i < sizeof(rom); i++) {
+    owi.one_wire_read_byte(rom[i]);
+    if (rom[i] < 0x10) Serial.print(0);
+    Serial.print(rom[i], HEX);
+    crc = one_wire_crc_update(crc, rom[i]);
+  }
+  Serial.println();
+  ASSERT(crc == 0);
+
+  // Search device on 1-Wire bus and print rom
+  uint8_t bits = 0;
+  uint8_t ix = 0;
+  uint8_t value = 0;
+  uint8_t dir = 0;
+  int8_t res = 0;
+  bool id;
+  bool nid;
+  crc = 0;
+  ASSERT(owi.one_wire_reset());
+  ASSERT(owi.one_wire_write_byte(SEARCH_ROM));
+  Serial.print(F("search_rom="));
+  do {
+    res = owi.one_wire_triplet(dir);
+    if (res < 0) break;
+    id = (res & 1) != 0;
+    nid = (res & 2) != 0;
+    value = (value >> 1);
+    if (dir) value |= 0x80;
+    bits += 1;
+    if (bits == CHARBITS) {
+      rom[ix] = value;
+      if (rom[ix] < 0x10) Serial.print(0);
+      Serial.print(rom[ix], HEX);
+      crc = one_wire_crc_update(crc, rom[ix]);
+      ix += 1;
+      bits = 0;
+      value = 0;
+    }
+  } while (id != nid);
+  Serial.println();
+  ASSERT(crc == 0);
+}
+
+void loop()
+{
+  // Convert and read temperature
+  ASSERT(owi.one_wire_reset());
+  ASSERT(owi.one_wire_write_byte(SKIP_ROM));
+  ASSERT(owi.one_wire_write_byte(CONVERT_T));
+  delay(750);
+
+  ASSERT(owi.one_wire_reset());
+  ASSERT(owi.one_wire_write_byte(SKIP_ROM));
+  ASSERT(owi.one_wire_write_byte(READ_SCRATCHPAD));
+
+  // Print scatchpad and calculate check sum
+  scratchpad_t scratchpad;
+  uint8_t* p = (uint8_t*) &scratchpad;
+  uint8_t crc = 0;
+  Serial.print(F("read_scratchpad="));
+  for (size_t i = 0; i < sizeof(scratchpad); i++) {
+    ASSERT(owi.one_wire_read_byte(p[i]));
+    if (i == sizeof(scratchpad) - 1) Serial.print(F(",crc="));
+    if (p[i] < 0x10) Serial.print('0');
+    Serial.print(p[i], HEX);
+    crc = one_wire_crc_update(crc, p[i]);
+  }
+  ASSERT(crc == 0);
+
+  // Print temperature (convert from fixed to floating point number)
+  Serial.print(',');
+  float temperature = scratchpad.temperature * 0.0625;
+  TRACE(temperature);
+  delay(2000);
+}

library.properties

@@ -1,9 +1,9 @@
 name=Arduino-TWI
-version=1.8
+version=1.9
 author=Mikael Patel
 maintainer=Mikael Patel <[email protected]>
 sentence=Two-Wire Interface (TWI) library for Arduino.
-paragraph=The TWI library is an abstract interface for I2C device drivers. The library includes a hardware and software implementation, and example device drivers for I2C Humidity and Temperature Sensor (Si70XX), Remote 8-bit I/O expander (PCF8574/PCF8574A), and Digital Pressure Sensor (BMP085).
+paragraph=The TWI library is an abstract interface for I2C device drivers. The library includes a hardware and software implementation, and example device drivers for I2C Humidity and Temperature Sensor (Si70XX), Remote 8-bit I/O expander (PCF8574/PCF8574A), Digital Pressure Sensor (BMP085), and Single/Multi-Channel 1-Wire Master (DS2482).
 category=Communication
 url=https://github.com/mikaelpatel/Arduino-TWI
 architectures=avr,sam

mainpage.dox

@@ -4,9 +4,10 @@ The TWI library is an abstract interface for I2C device drivers. The
 library includes a Hardware::TWI and Software::TWI bus manager
 implementation, and example device drivers for I2C Humidity and
 Temperature Sensor (Si70XX), Remote 8-bit I/O expander (PCF8574 and
-PCF8574A), and and Digital Pressure Sensor (BMP085).
+PCF8574A), Digital Pressure Sensor (BMP085), and Single/Multi-Channel
+1-Wire Master (DS2482).
 
-Version: 1.8
+Version: 1.9
 */
 
 /** @page License