diff --git a/docs/knownlimitations.md b/docs/knownlimitations.md index 977cd1d2..ec3d9b7a 100644 --- a/docs/knownlimitations.md +++ b/docs/knownlimitations.md @@ -7,16 +7,16 @@ such sensors and known workarounds if they exist. #### Grove Sensors - * **Grove I2C Touch Sensor** v1.3 is incompatible with the Intel Edison using - the Arduino board, but will work with the Mini-breakout if supplied with at - least 4V. Revision v1.2 works well on all Intel boards. + * **Grove I2C Touch Sensor** (MPR121) v1.3 is incompatible with the Intel + Edison using the Arduino board, but will work with the Mini-breakout if + supplied with at least 4V. Revision v1.2 works well on all Intel boards. * **Grove Nunchuck** only works with the Intel Galileo boards and is unusable on the Intel Edison boards. * **Grove 3-Axis Digital Gyroscope** (ITG-3200) is not compatible with the Intel Edison Arduino board but will work with the Mini-breakout. * **Grove 3-Axis Digital Accelerometer** (ADXL345) only works with the Intel Edison Arduino board when powered from the 3.3V line. - * **Grove 3-Axis Digital Compass (HMC5883L) reports inaccurate values at 5V + * **Grove 3-Axis Digital Compass** (HMC5883L) reports inaccurate values at 5V on the Intel Edison Arduino board and newer revisions might not work at all. Use 3.3V or the Mini-breakout. * **Grove 96x96 OLED Display** will not work on the Intel Edison with Arduino @@ -26,6 +26,9 @@ such sensors and known workarounds if they exist. * **Grove Barometer** (BMP085) has an unstable connection on the Intel Edison using the Arduino breakout and may drop read data. The Xadow version of this sensor (BMP180) is also dropping data packets occasionally. + * **Grove Digital Light Sensor** (TSL2561) occasionally drops I2C reads on the + Intel Edison with the Arduino breakout. This might cause the sensor not to + initialize properly. Works as expected with the Mini-breakout. * **Grove 6-Axis Accelerometer & Compass** (LSM303) fails to write to the configuration register properly and returns invalid data. * **Grove I2C ADC Converter** does not show up on the I2C bus on the Intel @@ -34,7 +37,8 @@ such sensors and known workarounds if they exist. the inability to change the I2C bus speed to 100 KHz. * **Grove CO2 Sensor** will return zeroed data and is unusable on the Intel Galileo. - * **Grove BLE** (HM-11) does not return data on the Intel Galileo board. + * **Grove BLE** (HM-11) does not return data on the Intel Galileo board due to + known UART limitation. #### Adafruit Sensors @@ -43,15 +47,27 @@ such sensors and known workarounds if they exist. #### Other Sensors - * **SM130** driver might not be fully functional. - * **NRF24L01** might not handle data packets as expected. - * **NRF8001** based devices do not initialize properly with provided examples. + * **NRF24L01** corrupted data packets are sent to the device due to the Intel + Edison SPI bus limitation. Sensor works as expected with the Intel Galileo + boards. + * **NRF8001** based devices do not initialize properly with provided examples + on Intel Edison boards also due to SPI bus limitation and data corruption. + Works on Intel Galileo. #### General -Some I2C sensors add too much capacitance to the SDA line of the Intel Edison +Some *I2C* sensors add too much capacitance to the SDA line of the Intel Edison Arduino breakout board, thus the signal sticks to a logic 1. When this happens, other sensors connected to the I2C bus are unusable. While there is no generic solution for this limitation, in most cases the sensor works on the Intel Edison Mini-breakout. When this board is not an option, the sensor can be sometimes replaced with the same model from a different vendor. + +The Intel Edison *SPI* bus can corrupt data being sent across when certain +sensors are connected to it. Based on the sensor, this can affect functionality +slightly or make the sensor entirely unusable. Unlike the I2C bus limitation, +different boards are not likely to resolve this. A kernel update on the other +hand might help alleviate this. + +On the Intel Galileo boards, the *UART* bus might drop data if several bytes +are read at once.