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TE0720 CPLD interfering with RTC I2C-bus signal

Started by dave74321, July 30, 2018, 09:52:15 AM

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dave74321

Hi,
I wish to develop TE0720-03-1CFA modules into our products.  There is a need to access the RTC chip.

However the CPLD module is not passing through the I2C-Bus signals correctly - the first few SDA toggles are not passed through from the RTC chip to the Zynq (Please see the attached image which shows sda_o, scl_o, sda_i within the Zynq and the sda signal on the RTC SDA pull-up resistor.

Is there something that needs to be controlled/setup within the CPLD to get it to pass the signals directly through without any interference?

Thanks


dave74321

Does anyone have the code that it is the CPLD? - so that I can see what it is doing??

Thanks

cfillot

Contrary to the carrier cards where the CPLD source code is available, the TE0720 CPLD source code does not seem to be present in the download area...
It would be great if it could be published (I would also need it for my eFuse problem...)



JH

Hi,

module source code of TE0720 is unfortunately not available.

We have RTC implemented into our reference design:

You can try out. Use our SC IP (Xilinx I2C interface to 3 wire I2C interface for CPLD). CPLD is only 3 wire to 2 wire I2C and add internal I2C to GPIO expander.  --> it's like the bidirectional buffer is moved from FPGA to CPLD).
CPLD description for TE0720 is on my todo. At the moment we have only some older description available:


br
John