I2C on MCF51 w/ processor expert

akak — Thu, 13 Mar 2008 05:51:28 GMT

Hello,

I am trying to interface with an SRF08 sonar using processor expert with the MCF51QE128. I have a couple questions:

1) Do I need to attach pull-up resistors to the I2C bus, or are these integrated onto the board?

2) I only get ERR_BUSY when I try to sendChar to my device (I already used selectSlave() to select the proper address).

Does anyone have any experience with this device or getting I2C to work on MCF51?

Thanks!

Re: I2C on MCF51 w/ processor expert

ProcessorExpert — Thu, 24 Apr 2008 18:12:46 GMT

The external pull-ups are necessary for communication via I2C bus.

ERR_BUSY means, that the slave device doesn't respond by an acknowledge. This may be caused either by pull-up missing on the line or by an incorrect slave address.

More detailed information about Sendchar() and SelectSlave() methods can be find in the help of the I2C bean on page Methods (in the pop-up menu of the I2C Bean).

Please specify what type of the demo board you are using. This information is missing in your issue.

For example:
External pull-up resistors for SDA and SCL lines are enabled by default on the DEMOQE128 board. Please see the 8.7 section in the user manual of the DEMOQE128 board.

Weblink to the user manual of the DEMOQE128:
http://www.freescale.com/files/microcontrollers/doc/user_guide/DEMOQE128UM.pdf?fpsp=1

Processor Expert Support Team
www.processorexpert.com

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I2C on MCF51 w/ processor expert

Re: I2C on MCF51 w/ processor expert