Friday, November 19, 2010

How to transmit I2C data to the slave IC?

Here is the example for you about sending I2C data into tuner as a slave.
Table below are write data format of I2C into the IC.
Figure 1. Write data format
Address byte (ADB) à address slave IC byte (write/read command)
Divider byte 1 dan 2 (DB1,2) à switching broadcasting frequency
Control byte 1 dan 2 (CB1,2) à slave IC setting for many think (see datasheet)
Band switch byte (BB) à band switching (VHF-L, VHF-H, UHF), charge pump, etc.
A à Acknowledge (information signal to the master for completing data receive and ready to receive next data)
In IC SN761668 (Texas Instrument)
Address byte : 11000010 (C2h) write command
Divider byte 1 : 00001011 (0Bh) freq. 474MHz, IF 36.167MHz
Divider byte 2 : 11110101 (F5h) Step size: 166.67kHz
Control byte 1 : 10010000 (90h)
Band Switch byte  : 11011000 (D8h) UHF band.
Control byte 2 : 11000010 (C2h)

I2C data are going to transmit have to be follow the sequence as a table above. There are different format in each slave IC type.
The communication data as like below approximation:

Figure 2. I2C data (example)
For the master IC program is up to you.
Need your feedback for wrong data communications.

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