You have lost the connection to the Coridium board. Power down, check connections repower, restart BASICtools...

Debugging involves walking before you can run. Once you made sure power is correct to both devices. Next you check whether the i2c SCL and SDA lines are wiggling (logic probe is fine, maybe even a meter) Then can you address the device? Note that the I2Cspeed50 must be done before I2C.bas (maybe tha...

I2C.bas treats the address as an 8 bit value with the LSB indicating read or write.

What that does tell me that the 80 address is decimal as 80 hex would be an 8 bit address not 7.

So there is something else going on.

While it mentions 80 as the default address in the spec, it never specifies hex or decimal. I see your code uses decimal, maybe its hex? But you should narrow down why the i2c routines are returning 0, which means ACKs are not being received.

Yes those pins are not normally open drain, but the I2C.bas routines either drive the pin low, or make it an input, effectively open drain. Check power to the display, make sure you are actually wiggling the right pins, if you don't have a scope, I posted a blog article about how to build a logic pr...

If i2c routines are returning 0, means the target device is NOT acknowledging.

Either miss wired, no pullups, or ...

As I read the spec sheet, the 254, 160, 0 command would be sent in SERIAL mode to return data in i2c mode If your jumpers are set to i2c that should not be needed. Did you change it to i2c (from spec sheet) The Protocol Select Jumpers provide the means necessary to toggle the GLK19264A-7T-1U between...

You really need to be more specific about the part numbers. The 4068 comes in lots of varieties, the CD4068 normally is powered by 5V and requires inputs higher than 3.3V to switch, so would require buffering or pullups. I'm not sure what a ULN2009 is (a typo maybe). Same goes for 40438. Spec sheets...

If you are using ULN2003A chips, you can drive those directly from the SuperPRO IO

They turn on at 2.4-2.7 V (from the spec sheet)

LPC1756 outputs 4mA (from the NXP spec sheet)

I have driven these directly before.

I don't have any i2c displays, always opted for either serial or SPI.

Do the displays you have supply code examples?

-- edit --

I was looking at the website for Matrix Orbital, very expensive, take a look at New Haven 1/5 the cost and we have published examples. Digikey also carries them.