#Arduino wire library choose bus how to
#Arduino wire library choose bus full
#Arduino wire library choose bus plus

Indication if any bytes sent successfully before error.

1:data too long to fit in transmit buffer.

However it is more than just callback functions that are likely to be required.įirst of all error handling EndTransmission has return codes of There are issues with RequestFrom and EndTransmission that make it more complicated to make them non-blocvking, but it is obviously possible as many other platforms have non-blocking I2C (or SMBUS that runs over I2C) in desktop PCs so the API CAN be made non-blocking.

Now defunct but still supported Due 84MHz 96kb RAM (32 bit 2 x I2C)Īll newer boards are likely to have more RAM and/or faster clock, faster clock alone will mean a lot more wasted cycles on blocking calls and more functions should be made non-blocking.

If we only consider the UNO as being the ONLY platform, the other platforms suffer.

#Arduino wire library choose bus plus

With more modern devices MEMS accelerometers and other more complex devices it is not uncommon for the data to be read to be 16 plus bytes so the blocking time is considerable. Yes it would be a good idea and yes it needs a lot of thought I'd really like to hear your opinions about how non-blocking Wire should Networking, time taken waiting for I2C can mean not responding to clients. Where the time taken for an I2C transfer becomes an issue. Performance projects, like complex LED animations and audio synthesis, Newer ARM & ESP boards are also much faster and capable of doing other When your only master-mode API waits for each transfer to complete. Ports, you can't even get more than 1 communicating at the same time Many newer boards have 2 or more I2C ports. Performance boards with only a single I2C port, the blocking Wire Of course, I'm sure someone reading this is thinking 'why do this atĪll, the Wire library has worked well for 10 years'. Or maybe there's some better non-blocking API than event callback functions? Non-blocking if the user has set up a completion callback function? Maybe 2 more of these could be added for master mode,Īnd the traditional requestFrom and endTransmission would become The library already has onReceive(function) and onRequest(function) usedįor slave mode.

Or maybe a complete function would be giving with something like: Later when the transfer completes, the function would be called. When given a function to call, requestFrom would immediately return. Wire.requestFrom(address, length, true, myfunction)

Perhaps another optional parameter could beĪdded for a function to be called? Such as: The 2 blocking functions are Wire.endTransmission() and Wire.requestFrom().Įach of these currently accepts an optional parameter for whether or not We developers work together for API compatibility. I believe everyone benefits in the long term when Ideally I would like to see this adopted by the officialĪrduino Wire library. Some Arduino compatible libraries do not allow to set I2C bus to use always use I2C1.One of my many goals this year is a non-blocking extension to the Wire.GPIO 34, 35, 36 and 39 are INPUT ONY ports and can not be used as SCL or SDA.ESP32 use matrix IO that allows mapping any pin to any function.

#Arduino wire library choose bus how to

In the following example, I will show how to use multiple I2C buses of ESP32 using Espressif core for Arduino.

#Arduino wire library choose bus full

Not only you can have more devices of the same type and avoid I2C address conflicts, but you can also take full advantage of 2 ESP32 cores and communicate with multiple devices at the same time. Here comes the advantage of having multiple I2C buses. If the bus is used by, for example, MPU6050, parallel communication with SSD1306 OLED display is not possible. However, one has to remember that one of the devices can be polled at a time. As long as slave device addresses are unique, everything will work just fine: OLED display, LM75 temperature sensor, MPU6050 gyroscope. Yes, the I2C bus allows connecting multiple slave devices to single pair of SCL SDA wires. One of the advantages of the ESP32 microcontrollers over the competitions is dual-core architecture and two I2C buses.