FRDM K20D50M I2C alternate channels

[thatonesaxkid]

Hey Freescale community,

I'm using the FRDM K20D50M board along with the Adafruit Motor Shield V2 (an Arduino shield). The shield requires that I send commands using I2C, where SCL is on PTB2 and SDA is on PTB3. After a long time searching through the schematic for the FRDM board, it looks like the board's I2C hardware can go through an alternate channel to reach those pins also, however, I am banging my head against the wall trying to find some sort of documentation about how to set up I2C for alternate channels. I am using Keil MDK-ARM which doesn't have any I2C driver for this board.

Any explanation or links to other posts, documentation, or code would be greatly appreciated.

Thanks!

Chris :smileyhappy:

[mjbcswitzerland · Accepted solution]

Christopher

_CONFIG_PERIPHERAL(B, 3,  (PB_3_I2C0_SDA | PORT_ODE | PORT_PS_UP_ENABLE)); // I2C0_SDA on PB3 (alt. function 2)
_CONFIG_PERIPHERAL(B, 2,  (PB_2_I2C0_SCL | PORT_ODE | PORT_PS_UP_ENABLE)); // I2C0_SCL on PB2 (alt. function 2)

That is set

PORTB_PCR3 = (0x00000223);

PORTB_PCR2 = (0x00000223);

Regards

Mark

P.S: See the table in the user's manual in the section "Signal Multiplexing and Pin Assignments"

[thatonesaxkid]

Thanks! Where can I find the user's manual? All I've found is this: http://cache.freescale.com/files/microcontrollers/doc/user_guide/FRDM-K20D50MUM.pdf which tells me basically nothing useful.

Chris

[mjbcswitzerland]

Chris

You need details of the chip and not the board:

http://www.freescale.com/webapp/sps/site/prod_summary.jsp?code=K20_50&lang_cd=en&webpageId=132640824...

http://www.freescale.com/webapp/sps/site/prod_summary.jsp?code=K20_50&nodeId=01624698C9DE2DDDA7&fpsp...

http://cache.freescale.com/files/32bit/doc/ref_manual/K20P48M50SF0RM.pdf?fasp=1&WT_TYPE=Reference%20...

Regards

Mark