IIC module functions in Freescale MC9S08SH8 8-bit MCU

[BrunoARG]

Hello everyone.

I am trying to interface a RTC IC (DS1307) with this MCU but I can't seem to get it done. I read the datasheet user manual and some AN buy I still don't understand how to configure and control this module.

There is an application note View attachment PERIFERICOS.pdf (the one I have attached, go to IIC/I2C section) which uses the same register names my MCU does.

I need a function which allows me to read and write data, no matter if it only does one read/write cycle per time. The MCU is the master and the RTC the slave.

Thank you in advance.

 

[Gorgon]

Why don't you download the referenced project HCS08QRUGSW.zip listed on page 53, with code to interface the I2C module?

This is a two-step process:
First you need to get the general I2C interface driver going,

and then to make the appropriate function layer to talk to the RTC.


Without knowing, I would suppose the first part is covered in the referenced project, possibly with a rudimentary application layer. So after that you need to understand how the RTC works from it's datasheet, and adjust/ work out your application.
I'm certain the there is several ANs for the DS1307 describing such a code, and Google will find them for you.

 

[BrunoARG]

Thank you for your answer.

I finally did something I don't like to, I just copied the given code from the same manufacturer IIC module application note and it worked. What I couldn't get working well is when I call the read function too frequently, the program seems to get stuck when it waits for the bus to be idle again. What I don't understand is that I call the function twice at the start and it works well, but then I call it twice again and that happens.

I made a program which worked with the DS1307 for a Microchip MCU but using pre-made libraries, now I am programming it in a Freescale with no libraries, just hand modified registers. I read how to call the DS1307 and which registers I have to modify to get it working. Actually it does but my program doesn't seem to work well.

I will try to avoid the read function when the bus is busy, before calling it.


EDIT: Using a bus idle condition I call the function when that is true, now my program will run correctly, I just need to modify it