remapping the I2C lines?

[offbeatmammal 0]

I am using a CC3200 LaunchPadXL and want to control the green and orange LEDs as well as access the on-board temperature sensor.

 

It appeared not possible, if I2C is used. In LAUNCHXL LEDs are wired to the same lines as onboard jumpers for I2C SCL and SDA lines.

 

I found a reference that seemed to indicate on a CC3200 other pins can be used for I2C and in the example they edited the file pinmux.c

          MAP_PinTypeI2C(PIN_05, PIN_MODE_5);  //I2C SCL

          MAP_PinTypeI2C(PIN_04, PIN_MODE_5);  //I2C SDA

I tried adding those lines to my Energia setup() {...} but it didn't seem to help

 

I tried removing the jumpers (J2 and J3) as per another suggestion but then the code appears not to run on the device at all

[chicken 630]

Did you already check out the Wire.SetModule() command? This should allow you to select between the two I2C channels (pins 9/10 or 39/40 according to the pin map).

[offbeatmammal 0]

Ah, there seems to be no mention of that in the Wire library reference - http://energia.nu/reference/wire/- can you point me to the parameter I would need to swap them (meantime I will go trawling Bing some more...) Thanks!

[chicken 630]

Seems to be a gap in the documentation of both Energia and the CC3200 pin map ( @@energia ).

 

The parameter n for setModule(n) is the module number, starting at 0. I'd try the numbers of the serial port (RX/TX) that share pins with I2C.

[offbeatmammal 0]

hmmm. adding a Wire.setModule(0); to my setup() gives the following error:

 

obm_01.cpp.o: In function `setup':

obm_01.cpp:(.text.setup+0x6): undefined reference to `TwoWire::setModule(unsigned long)'

collect2: error: ld returned 1 exit status

 

looking at the source in https://github.com/energia/Energia/tree/master/libraries/Wire there doesn't appear to be a setModule function defined, and there was a discussion (back in 2013) that didn't seem to go anywhere - https://github.com/energia/Energia/issues/285

 

am I missing something obvious (see "noob class" label!) or should I file a bug and hope we can get a fix (cc @@energia )?

[energia 485]

setModule is not available for CC3200. There is only one I2C peripheral. Below is the answer to your question I just posted on e2e:

 

"Unfortunately there are not a lot of options here. The is only 1 I2C peripheral and not all pins are brought out to the LaunchPad headers.

1: pin 1/2 are the default and routed to pins 9/10 of the BoosterPack header.

2: pin 3/4 are already connected to TX/RX of the UART which is pins 3/4 of the BoosterPack header and connected to the FTDI chip. You could potentially give up the UART (Serial) and use these pins for I2C. Energia however is not setup to use these pins for I2C and you would have to modify the Wire library to enable them.

3: pin 5/6 could be an option but then you would give up SPI since SPI CLK is on pin 7 of the BoosterPack header. Same as 2, this would require modification of the Wire library.

4: pin 16/17 are JTAG"

 

Robert

[offbeatmammal 0]

Thanks (for reply here and on e2e). So essentially I am out of luck... Either the LEDs keep glowing, or I have to use an off-board temp sensor and pull the jumpers?

If there is a way to do it with Energia just while I am playing around D it would be great, as then I can actually use the three lights in a more meaningful way...

[energia 485]

Unfortunately there is no way to use the onboard sensors and the LED's at the same time.

[offbeatmammal 0]

thanks

guess it's time to work out how to attach something to the Launchpad so I can control my own LEDs