topic Re: Unable to communicate using external I2C in CodeWarrior Development Tools

Unable to communicate using external I2C

jmu — Tue, 20 Sep 2016 22:17:01 GMT

Hi,

I have a question regarding the external I2C block in Processor expert. I am using CodeWarrior version 10.6.4 and the micro controller is part of the MC9S12ZVC family and I am using a USB multilink universal debugger to communicate. I am trying to receive messages from my processor to a tilt sensor (MMA8653FCR1). When I step into the code of the receive block (EI2C1_RecvBlock) it looks like the data is never received.

As per the code above, the value of acknowledge is always set to '1' which I assume means that the tilt sensor has received the data request. Below is a screenshot of the configuration -

Is there some sort of basic mistake that I am committing ? Also am I supposed to see pulses in the IICSCL or IICSDA lines when I transmit data (using EI2C1_SendBlock) ?

Once again I would deeply appreciate it if someone could provide some insight.

Sincerely,

Mahendra

Re: Unable to communicate using external I2C

Alice_Yang — Wed, 21 Sep 2016 09:26:22 GMT

Hello Mahendra,

First i recommend you use one Scope to check the send signal and

receive signal on IICSCL and IICSDA lines .

If the signal is right , then you can refer to the Typical usage : right click

the component , then select "help on component" :

Hope it helps

Alice

Re: Unable to communicate using external I2C

jmu — Wed, 21 Sep 2016 20:27:58 GMT

Hi Alice,

Thank you for your quick response. I connected the IICSDA and IICSCL lines to a scope. The IICSDA line is being pulled upto 4.5 volts and IICSCL line stays at 0 volts. I am not seeing a pulse in either of the lines. Do you think there is a register I need to set in order to see the clock pulses ?

I assigned the register IIC0IBCR register to 0xB0 which enables IIC bus module, sets Master mode and sets the transmit bit. Although when I do this the register IIC0IBSR gets set to 0xA4.

Do you think this could be one of the problems ?

Below is a snippet of the part of the code which transmits and receives data -

It looks like the main problem is the lack of clock pulses on the IIC0SCL line. Do let me know your thoughts.

Once again deeply appreciate your insight.

Sincerely,

Mahendra

Re: Unable to communicate using external I2C

Alice_Yang — Thu, 22 Sep 2016 07:22:45 GMT

Hello Mahendra,

- Please pay attention that , if you use the processor expert , you needn't configure

the registers for initialize I2C . After configure the I2C component , then the initialize

code can generate :

-From your detail of the IICSDA and IICSCL signal, i think the I2C have not been start ..

So recommend you first refer the demo i mentioned last time to test .

Alice