add multi tca code

Author: caternuson

I2C_Multiple_Same_Address/arduino/multi_tca_2x/multi_tca_2x.ino

@@ -0,0 +1,77 @@
+// SPDX-FileCopyrightText: 2022 Carter Nelson for Adafruit Industries
+//
+// SPDX-License-Identifier: MIT
+
+#include <Adafruit_BME280.h>
+
+// for each TCA9548A, add an entry with its address
+const uint8_t TCA_ADDRESSES[] = {
+  0x70,
+  0x71
+};
+const uint8_t TCA_COUNT = sizeof(TCA_ADDRESSES) / sizeof(TCA_ADDRESSES[0]);
+
+Adafruit_BME280 bme1;  // BME280 #1
+Adafruit_BME280 bme2;  // BME280 #2
+Adafruit_BME280 bme3;  // BME280 #3
+
+void tcaselect(uint8_t tca, uint8_t channel) {
+  if (tca >= TCA_COUNT) return;
+  if (channel > 7) return;
+
+  // loop over all TCA's
+  for (uint8_t i=0; i<TCA_COUNT; i++) {
+    Wire.beginTransmission(TCA_ADDRESSES[i]);
+    if (i == tca)
+      // set output channel for selected TCA
+      Wire.write(1 << channel);
+    else
+      // for others, turn off all channels
+      Wire.write(0);
+    Wire.endTransmission();
+  }
+}
+
+
+void setup() {
+  Serial.begin(9600);
+  while(!Serial);
+  Serial.println("Multiple BME280 / Multiple TCA9548A Example.");
+
+  Serial.print("Total number of TCA's = "); Serial.println(TCA_COUNT);
+  for (uint8_t i=0; i<TCA_COUNT; i++) {
+    Serial.print(i); Serial.print(" : 0x"); Serial.println(TCA_ADDRESSES[i], 16);
+  }
+
+  // NOTE!!! VERY IMPORTANT!!!
+  // Must call this once manually before first call to tcaselect()
+  Wire.begin();
+
+  // Before using any BME280, call tcaselect to select its output channel
+  tcaselect(0, 0);   // TCA 0, channel 0 for bme1
+  bme1.begin();      // use the default address of 0x77
+
+  tcaselect(0, 1);   // TCA 0, channel 1 for bme2
+  bme2.begin();      // use the default address of 0x77
+
+  tcaselect(1, 0);   // TCA 1, channel 0 for bme3
+  bme3.begin();      // use the default address of 0x77
+}
+
+void loop() {
+  float pressure1, pressure2, pressure3;
+
+  tcaselect(0, 0);
+  pressure1 = bme1.readPressure();
+  tcaselect(0, 1);
+  pressure2 = bme2.readPressure();
+  tcaselect(1, 0);
+  pressure3 = bme3.readPressure();
+
+  Serial.println("------------------------------------");
+  Serial.print("BME280 #1 Pressure = "); Serial.println(pressure1);
+  Serial.print("BME280 #2 Pressure = "); Serial.println(pressure2);
+  Serial.print("BME280 #3 Pressure = "); Serial.println(pressure3);
+
+  delay(1000);
+}

I2C_Multiple_Same_Address/circuitpython/multi_tca_2x/code.py

@@ -0,0 +1,40 @@
+# SPDX-FileCopyrightText: 2022 Carter Nelson for Adafruit Industries
+#
+# SPDX-License-Identifier: MIT
+
+import time
+import board
+import adafruit_tca9548a
+from adafruit_bme280 import basic as adafruit_bme280
+
+# Create I2C bus as normal
+i2c = board.I2C()
+
+#--------------------------------------------------------------------
+# NOTE!!! This is the "special" part of the code
+#
+# For each TCA9548A, create a separate instance and give each
+# the *same* I2C bus but with specific address for each
+tca1 = adafruit_tca9548a.TCA9548A(i2c, 0x70)   # TCA with address 0x70
+tca2 = adafruit_tca9548a.TCA9548A(i2c, 0x71)   # TCA with address 0x71
+# Create each BME280 using the TCA9548A channel instead of the I2C object
+# Be sure to use the TCA instance each BME280 is attached to
+bme1 = adafruit_bme280.Adafruit_BME280_I2C(tca1[0])   # TCA 1 Channel 0
+bme2 = adafruit_bme280.Adafruit_BME280_I2C(tca1[1])   # TCA 1 Channel 1
+bme3 = adafruit_bme280.Adafruit_BME280_I2C(tca2[0])   # TCA 2 Channel 0
+#--------------------------------------------------------------------
+
+print("Multiple BME280 / Multiple TCA9548A Example")
+
+while True:
+    # Access each sensor via its instance
+    pressure1 = bme1.pressure
+    pressure2 = bme2.pressure
+    pressure3 = bme3.pressure
+
+    print("-"*20)
+    print("BME280 #1 Pressure =", pressure1)
+    print("BME280 #2 Pressure =", pressure2)
+    print("BME280 #3 Pressure =", pressure3)
+
+    time.sleep(1)