TCS34725 RGB sensor with i2c interface fails

[bbx10]

The TCS34725 i2c RGB color sensor returns garbage RGB values using board package 1.6.4-673-g8cd3697. Since there are 3 changes to the i2c driver since the 1.6.4 release, I copied core_esp8266_si2c.c from master and overwrote the version installed with 1.6.4. The TCS sensor now works based on limited testing.

Since the fix is on master should I close this issue? I posted just in case someone is working with this sensor.

[bbx10]

The sensor is still returning garbage values often enough to make it useless. Sometimes the sensor gets stucks returning garbage until it is reset.

When comparing logic analyzer traces of 16 bit reads, the last byte is followed by NACK. This is correct according to the i2c spec because the NACK tells the slave-sender to not send another byte.

With this change, the sensor behaves about the same as when it is connected to an Uno.