Merge pull request #54 from meetjestad/configurable-wire-bus

Allow using secondary Wire buses

Author: psachs

sensirion_hw_i2c_implementation.cpp

@@ -35,14 +35,6 @@
 // needed for delay() routine
 #include <Arduino.h>
 
-#include <Wire.h>
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-
-
 #ifdef SPS30_USE_ALT_I2C
 #include "i2c_master_lib.h"
 
@@ -77,14 +69,22 @@ int8_t sensirion_i2c_write(uint8_t address, const uint8_t *data, uint8_t count)
 
 #else /* SPS30_USE_ALT_I2C */
 
+static TwoWire *sensirion_wire_object;
+
 /**
  * Initialize all hard- and software components that are needed for the I2C
  * communication. After this function has been called, the functions
  * i2c_read() and i2c_write() must succeed.
  */
+void sensirion_i2c_init(TwoWire& wire)
+{
+   sensirion_wire_object = &wire;
+   sensirion_wire_object->begin();
+}
+
 void sensirion_i2c_init()
 {
-   Wire.begin();
+    sensirion_i2c_init(Wire);
 }
 
 void sensirion_i2c_release(void)
@@ -95,11 +95,14 @@ int8_t sensirion_i2c_read(uint8_t address, uint8_t *data, uint8_t count) {
     uint8_t readData[count];
     uint8_t rxByteCount = 0;
 
+    if (!sensirion_wire_object)
+        return -1;
+
     // 2 bytes RH, 1 CRC, 2 bytes T, 1 CRC
-    Wire.requestFrom(address, count);
+    sensirion_wire_object->requestFrom(address, count);
 
-    while (Wire.available()) {  // wait till all arrive
-        readData[rxByteCount++] = Wire.read();
+    while (sensirion_wire_object->available()) {  // wait till all arrive
+        readData[rxByteCount++] = sensirion_wire_object->read();
         if (rxByteCount >= count)
             break;
     }
@@ -111,9 +114,12 @@ int8_t sensirion_i2c_read(uint8_t address, uint8_t *data, uint8_t count) {
 
 int8_t sensirion_i2c_write(uint8_t address, const uint8_t *data,
                            uint8_t count) {
-    Wire.beginTransmission(address);
-    Wire.write(data, count);
-    Wire.endTransmission();
+    if (!sensirion_wire_object)
+        return -1;
+
+    sensirion_wire_object->beginTransmission(address);
+    sensirion_wire_object->write(data, count);
+    sensirion_wire_object->endTransmission();
 
     return 0;
 }
@@ -129,7 +135,3 @@ int8_t sensirion_i2c_write(uint8_t address, const uint8_t *data,
 void sensirion_sleep_usec(uint32_t useconds) {
     delay((useconds / 1000) + 1);
 }
-
-#ifdef __cplusplus
-}  // extern "C"
-#endif

sensirion_i2c.h

@@ -33,23 +33,23 @@
 #define SENSIRION_I2C_H
 
 #include "sensirion_arch_config.h"
+#if defined(__cplusplus)
+#include <Wire.h>
+#endif
+
+// When included from C++, add a version of the init function that
+// accepts a Wire bus to use (in addition to the argumentless C-linkage
+// version defined below.
+// If SPS30_USE_ALT_I2C is defined, a fixed (local) I2C implementation
+// is used instead.
+#if !defined(SPS30_USE_ALT_I2C) && defined(__cplusplus)
+void sensirion_i2c_init(TwoWire& wire);
+#endif
 
 #ifdef __cplusplus
 extern "C" {
 #endif /* __cplusplus */
 
-/**
- * Select the current i2c bus by index.
- * All following i2c operations will be directed at that bus.
- *
- * THE IMPLEMENTATION IS OPTIONAL ON SINGLE-BUS SETUPS (all sensors on the same
- * bus)
- *
- * @param bus_idx   Bus index to select
- * @returns         0 on success, an error code otherwise
- */
-int16_t sensirion_i2c_select_bus(uint8_t bus_idx);
-
 /**
  * Initialize all hard- and software components that are needed for the I2C
  * communication.

sps30.h

@@ -32,14 +32,15 @@
 #ifndef SPS30_H
 #define SPS30_H
 
-#ifdef __cplusplus
-extern "C" {
-#endif
 
 #include "sensirion_arch_config.h"
 #include "sensirion_common.h"
 #include "sensirion_i2c.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #define SPS30_I2C_ADDRESS 0x69
 #define SPS30_MAX_SERIAL_LEN 32
 /* 1s measurement intervals */