#Arduino due i2c update#
#Arduino due i2c code#

An extraneous reset on the processor will generally create this condition, especially if the processor cannot save its status. The problem is that the master has forgotten where it was when it was interrupted or reset. The slave is still waiting to send the remainder of the data requested by the master. Initially this looks like a device problem, but it is not. The Analog Devices “ Implementing an I2C Reset” suggests :įrequently the master, which is usually a microcontroller or a gate array, will be interrupted in the middle of its communication with an I2C slave and, upon return, find a stuck bus. There are many scenarios when something like this can occur. The bus relies on orderly communication and if a device holds one of these lines low you’re in trouble.

There are two “Bus Stuck” scenarios: either the SDA or SCL lines become held low. Each device has an address on the bus and will only speak when spoken to by the Master.įor the purposes of this article I shall just look at what can go wrong and how we might recover from it. With a potential multitude of devices hanging off this same bus, they must play nicely with each other, and in order to do this, there is often a Master and number of Slave devices. It is an incredibly useful interface and you can hang a multitude of very useful chips off just these two wires, for example Real-Time Clocks, EEPROM memories, Accelerometers, interface expands, etc. These should normally sit high at whatever voltage your system is running at ie 5V or 3V3. The i2c (Inter-IC Communication) Bus consists of 2 wires (hence often called Two-Wire Interface aka TWI when you want to avoid using the i2c licensed term) the Data (SDA) and Clock (SCL).

Recover from and remove the bus lock-up condition.

Prevent a bus-lockup from hanging your system.

This article discusses techniques that you can use to try and make your system more fault-tolerant and attempt to recover from any errors. If you are trying to operate a remote or embedded system, this is not ideal.

#Arduino due i2c update#

I will try to update this with more detail connection if needed but my intent at the moment is to share the modification to the library files in order to make them work.It’s not unheard of for the i2c bus to “lock-up” on you, which can stop your system from working. The connection I used are simple, From the shields or DS1307-RTC I just feed them through a bi-level i2C safe board (I bought mine from Adafruit) and the output side I connect the 2 SCLs together and 2 SDAs together and feed them to the SCL1, SDA1 of the Due. Luckily the RTC clock and RGBLCDShield already has built in pull up resistors.

What is the point of having i2C if each device use their own pins right? Anyway, because the built-in SDA1 and SCL1 have no pull up resistors, these will be the one to use according to the posts I read so far. However, I want to be able to share this with SDA1 and SCL1 pin on the Due. Originally the RTC clock using RTClib.h by default can only be used on SDA(20) and SCL (21). It is very difficult, anyway I am able to put together some instruction here with hope it may be useful for someone. I am a novice so when reading 'just change Wire to Wire1' and go to this folder and include this and that.

#Arduino due i2c code#

What I think is lacking is for someone to actually clearly setup an entire code for someone to see. I did have to do modification as everyone mention in the other posts. I just want to share that I am able to share SCL1,SDA1 pin between RTC clock using Adafruit RTClib.h library with their RGBLCDShield.