IOException: Error reading from I2CDevice on I2CBus '1' ('/dev/i2c-1') at address 0x8 to address 0x1. Got '-1'.

[kpolleck]

After getting my new GoPiGo2 Robot working with the Python example, I tried to set up the Java library, but when running Test.sh, I get the immediate error:

IOException: Error reading from I2CDevice on I2CBus '1' ('/dev/i2c-1') at address 0x8 to address 0x1. Got '-1'.

The java program doesn't exit, and movement commands seem to still work (move forward / move backward / turn right / turn left / etc.) but other commands (e.g. led commands, "board revision," etc.) fail--some of them causing the java program to exit.

I'm wondering...is it possible that whomever wrote this had other accessories attached which might avoid the IOExceptions I am seeing?

[DexterInd]

@marcellobarile , do you have any idea what might have happened?

[marcellobarile]

hi @kpolleck,
can you please tell me the firmware version which is installed on your GoPiGo? I'll try to reproduce the issue with yours.

Best regards

[kpolleck]

Thanks. It's a GoPiGo2. I'll have to check it when I'm home and let you know.

While we are waiting for that, I'm wondering this: This error occurs every minute or two while everything is idle. Is there some sort of polling in the java library?

[kpolleck]

I also found this http://forum.dexterindustries.com/t/io-read-error/1330/13 suggesting setting:

#Decrease the baud rate?
dtparam=i2c_arm_baudrate=16000 # original suggestion was "dtparam=i2c_arm_baudrate=32000"

I have not tried that yet. Would you recommend it?

[marcellobarile]

Hello @kpolleck,
it might be the voltage checking timer (which ticks every minute).

I look forward to knowing the details of your environment (if possible can you also provide some OS information + Java version, thanks); consider that there might be some breaking change in the newer releases of the pi4j library.

Have a nice day

[marcellobarile]

Nice catch @kpolleck, I was unaware of that thread... I'd say that it might be worthy to give it a try but, if you prefer, I can dig into it a little bit.

[kpolleck]

The baudrate change resolved the problem.

For the record, my other information is:

Robot: GoPiGo2

Pi: Raspberry Pi3

Firmware version::1.6

Board revision:826

Java:
Java(TM) SE Runtime Environment (build 1.8.0_65-b17)
Java HotSpot(TM) Client VM (build 25.65-b01, mixed mode)

[marcellobarile]

awesome @kpolleck! @DexterInd do you think is there something that I can do codewise? Are you guys aware of this case?

[DexterInd]

@karan259 ?