I2C Ports on 32910 Propeller Activity Board?

oakguy

I have the HCM5883L compass board that requires or calls for attachment to the SDA and SCL ports. I don't see those ports are available. Is there a work around for the using data pins instead? Researching myself but I thought I might query the board!

Thanks

dgately

oakguy wrote: »

I have the HCM5883L compass board that requires or calls for attachment to the SDA and SCL ports. I don't see those ports are available. Is there a work around for the using data pins instead? Researching myself but I thought I might query the board!

You can use almost any of the propeller's digital I/O pins, but here are some good examples of what pins to use and how to code for this...

For Spin:
http://learn.parallax.com/KickStart/29133


For C (using SimpleIDE):

Look in the path "SimpleIDE:learn:Simple Libraries:Sensor:" for the "libcompass3d" directory...

Inside that directory, you'll see:
[LIST]
[*]Documentation compass3d Library.html  <= open this in a web browser for documentation on this library which works with the HCM5883L
[*]libcompass3d.c <= example code for using the HCM5883L in C
[/LIST]How to:[LIST=1]
[*]In SImpleIDE, open the above-mentioned file named "libcompass3d.c" in "SimpleIDE:learn:Simple Libraries:Sensor:libcompass3d:"
[*]Select the "Set Project View" option from the "Tools" menu
[*]Click the "Set Project to Current Tab" button, Or use the "Set Project" option from the "Project" menu, OR use the F4 key
[*]"Save As" the new project, naming it something you will remember :-)
[*]You should be able to compile this example!
[/LIST]

I hope this helps!

dgately

Mike Green

There is no specific I2C port on the Propeller although I/O pins 28 & 29 are used for the standard program EEPROM. I/O pins 30 & 31 are used for the serial connection to a PC. After the reset initialization is complete and a program is running, any I/O pin can be used for any sort of operation except for video where they're grouped into 4 possible VGA groups (8 pins each) and 8 possible TV groups (4 pins each).

Duane Degn

I don't see a way of accessing P28 and P29 on the Activity Board. As dgately suggests, you'll need to use one of the general purpose pins (P0 - P15). You'll want to use pull-up resistors on the I2C lines. 10K resistors pulled to 3.3V seems to be the norm with the Propeller.

Publison

Welcome to the forum!

The nice thing about the Propeller is that you can any pins to any hardware output. You can use a variety of objects in the OBEX to use in SPIN, the native Propeller language, or C as dgately has shown. You can also use Pins 28 and 29 that you could share with and EEPROM.

New questions are always welcome here.

EDIT Dang!! I have to learn how to type faster. Mike and Duane where first, as usual.
Duane..good call on the lack of access on P28.P29

oakguy

dgately wrote: »

You can use almost any of the propeller's digital I/O pins, but here are some good examples of what pins to use and how to code for this...

For Spin:
http://learn.parallax.com/KickStart/29133


For C (using SimpleIDE):

Look in the path "SimpleIDE:learn:Simple Libraries:Sensor:" for the "libcompass3d" directory...

Inside that directory, you'll see:
[LIST]
[*]Documentation compass3d Library.html  <= open this in a web browser for documentation on this library which works with the HCM5883L
[*]libcompass3d.c <= example code for using the HCM5883L in C
[/LIST]How to:[LIST=1]
[*]In SImpleIDE, open the above-mentioned file named "libcompass3d.c" in "SimpleIDE:learn:Simple Libraries:Sensor:libcompass3d:"
[*]Select the "Set Project View" option from the "Tools" menu
[*]Click the "Set Project to Current Tab" button, Or use the "Set Project" option from the "Project" menu, OR use the F4 key
[*]"Save As" the new project, naming it something you will remember :-)
[*]You should be able to compile this example!
[/LIST]

I hope this helps!

dgately

Very cool and very helpful!