Question about I2C

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Joined: Thu Jan 31, 2008 8:39 am

Question about I2C

Postby johan.b » Fri Feb 15, 2008 8:49 am

Good morning all,

I have tried to use the I2C Master for my application and I have some questions concerning it.
My dspic reads I2C data, but the sequence of data changes as a function of the operating mode.

The state machine has 6 modes and these modes are identified by numbers: 1,2,3,4,5 and 6

In practice I have 2 sequences:

- The 1st for the operating mode numbers 2, 4 and 6. The dspic must read 12 words in these modes.
- The 2nd for the operating mode numbers 1, 3 and 5. The dspic must read 18 words in these modes.

At present, I have no available simulink model and I don't see how to manage this with the I2C master.

Maybe that anybody can help me ? Thank you in advance.


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Re: Question about I2C

Postby LubinKerhuel » Mon Feb 18, 2008 11:10 pm

Hi Johan,

On the example I have build, I read only
- 4 data for states 1 ; 3 and 5
- 2 data for states 2 ; 3 and 6
But you can easily adapt it to read 18 and 12 data.

I use an Enabled Subsystem to choose wether I am reading 4 or 2 data.

The model :

I use a bus to gather the data. When reading only 2 data, I place 0 into into the unfilled data.
Using a bus with a constant width of 4 is up to you. You could use the I2C data in a different way.
FSM_1_3_5.png (14.85 KiB) Viewed 2267 times
FSM_2_4_6.png (12.26 KiB) Viewed 2268 times

The merge block output the most recent data (refere to simulink help)

(39.31 KiB) Downloaded 215 times

Posts: 8
Joined: Thu Jan 31, 2008 8:39 am

Re: Question about I2C

Postby johan.b » Thu Feb 21, 2008 9:25 am

Hello Lubin and thank you for your answer.
I will test your model and adapt it to my need.
Thank you.

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