HD44780 module error

I thought I would start playing with some modules today. The first one I tried was the HD44780 using the I2c example. When I try to run it I get this error.

This is the code...

I2C1.setup({scl:B6, sda:B7}); 
var lcd =require("HD44780").connectI2C(I2C1); 
lcd.print("Hello World!");

This is the error returned.

Uncaught Error: Field or method "print" does not already exist, and can't create it on undefined
 at line 2 col 7
4,e,e])}
       ^
in function "a" called from line 1 col 8
{a(51,1);a(50,1);a(40,1);a(12,1);a(6,1);­a(1,1);return{write:...
        ^
in function "f" called from line 2 col 9
4,e,e])})}
         ^
in function "connectI2C" called from line 1 col 45
var lcd = require("HD44780").connectI2C(I2C1);
                                             ^
 at line 1 col 4
lcd.print("Hello World!");
    ^

Any suggestions?

Are you using an up to date firmware?

Looks like there should really have been an error about I2C timeouts before the one about print - I was pretty sure that's something that got fixed recently.

However I reckon the issue is that the display isn't wired up right. Maybe SDA/SCL are crossed over, or maybe they don't have pullup resistors on them? I don't think those displays have them built in.

Do you get any errors if you leave off the lcd.print() command?

If so can you post that?

Also, do console.log(lcd) and see if there's anything there. I suspect the connectI2C() is encountering an error, resulting in there being no lcd object - so there's no print method.

Turns out that my board uses a different IO expander chip. I then used parallel interface and it worked fine. Sorry for the mix up.

I am curious how you change the I2c address without editing the module as it seems to be hard coded in?

Interesting - do you have a link to the module? This is the first time this has come up.

You'd have to change the module I'm afraid. To be honest a different IO expander IC might well behave in a different way (or be wired differently), so changing the address might not be enough.

If you want to play around with getting it working, try adding exports={}; at the top of the RHS of the Web IDE, copy and paste in the existing module and do var lcd = exports.connectI2C(I2C1); at the bottom to test it.

You could then play around with a different address/different commands to see if it works. We could then put the changes back in (either allowing the address to be changed, or it more was needed, having a separate function for your new driver IC).

Its the LCD backpack from adafruit.

I have a module in python that I wrote for it. Perhaps I can port it over.

Eep - yes, we should definitely support the Adafruit version. Actually it looks like this came up a few weeks ago, with *yet another IO chip in a module made by Adafruit!

http://forum.espruino.com/conversations/­272048/

Adafruit has some Arduino code up for this one as well, at https://github.com/adafruit/LiquidCrysta­l

Looks like it'll have to be a new function, as the I2C commands are definitely different.

A connectMCP23008 function should be pretty easy though. i2c.writeTo(0x20,9,data) should handle the write once the IO direction is set.