topic Re: I2C Basics in Kinetis Microcontrollers

I2C Basics

bitjockey — Thu, 19 Nov 2015 16:26:51 GMT

Hello All,

Newbie to using I2C on a KE06 FRDM board. I set the PE component up per the help file on it in KDS. (I2C1 channel on PTE0 and PTE1) I have the interrupt setting the transmitted flag True and a timer loop that transmits the same message every 160mS. I have the 4.7k pullups on the line. My question is if I don't have another I2C device connected to the bus should I be able to see the clock and data lines toggling with a scope? Or must a slave device be connected for I2C to operate properly? Currently the interrupt never fires and the program is stuck here: Highlighted in red.

CI2C1_SelectSlaveDevice(I2C1_Ptr, LDD_I2C_ADDRTYPE_7BITS, SlaveID); /* Select Slave to write to */

Error = CI2C1_MasterSendBlock(I2C1_Ptr, OutDataPtr, 4U, LDD_I2C_SEND_STOP); /* Send OutData (4 bytes) on the I2C bus and generates a stop condition to end transmission */

while (!DataTransmittedFlg) { /* Wait until OutData are transmitted */

}

DataTransmittedFlg = FALSE;

Regards,

Brian

Re: I2C Basics

bitjockey — Thu, 19 Nov 2015 16:50:05 GMT

Read a little more on the I2C spec, I am supposing since there is no slave, i.e., no ack bit that this would cause my issue???

Re: I2C Basics

carlos_neri — Thu, 26 Nov 2015 18:09:06 GMT

You will see the clocks and slave address on the data line and a NACK as you mention. you might want to look for a function on the PE generated code that asks for the transaction status, which probably sets a "NACK Received" flag.

Re: I2C Basics

mjbcswitzerland — Thu, 26 Nov 2015 21:48:11 GMT

Brian

See http://www.utasker.com/kinetis/FRDM-KE06Z.html which includes KE06 I2C operation, including simuation of the KE06, I2C and the accelerometer.

If using PE you may find that nothing is in fact controlling the DatatransmittedFlg and you may need to add its control in the I2C interrupt.

Regards

Mark

Kinetis: http://www.utasker.com/kinetis.html

I2C: http://www.utasker.com/docs/uTasker/uTaskerIIC.PDF

KE: http://www.utasker.com/kinetis/FRDM-KE02Z.html / http://www.utasker.com/kinetis/FRDM-KE02Z40M.html / http://www.utasker.com/kinetis/FRDM-KE04Z.html / http://www.utasker.com/kinetis/FRDM-KE06Z.html

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