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Matt1
Beginner
369 Views

issue in routing HPS I2C to FPGA in A10 SoC

Hi,

I have a requirement to route the I2C(master) in HPS to FPGA and connect the I2C signals to an I2C slave IP(IO Expander logic).I tried to in the following way 

under parameter(hard processing system intel arria10 FPGA IP-->Pin Mux and peripherals-->Advanced FPGA placement(under route to FPGA I changed the dropdown corresponding to I2C0 as Yes)

I am a bit doubtful about the I2C IP configuration,  SCL  signal is declared as input in the HPS signal list in platform designer system content tab.

is it possible to configure the I2C in HPS as master and route it to FPGA?

 

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6 Replies
sstrell
Honored Contributor II
358 Views

The I2C is a peripheral of the HPS.  As such, it's accessed by the FPGA over the bridges between the two halves of the device (h2f, f2h), typically through the address map of the HPS.

Matt1
Beginner
336 Views

thanks for the reply sstrell,

I am checking the possibility of the I2C which is explained in 4038 of Intel® Arria 10® Hard Processor
System Technical Reference Manual.

Matt1_0-1602562538665.png

 

Eliath_G_Intel
Employee
302 Views

Hi Nithin,

First of all, thank you for reaching us.

 

Regarding your issue... yes it is possible to configure the I2C in HPS as master and route it to FPGA, to do this please take a look into the next documentation, page #11, you will find a couple of lines for instantiation, you will need to copy them and add them to your *.v file

 

Regards,

-Eliath

 

Matt1
Beginner
272 Views

hello,

Thankyou Eliath for your reply

i understand the ALT_IOBUF Primitive  instantiation.

In the attachment, I have highlighted the pins of I2C which will be visible to FPGA and that looks like slave .

for example: what I understand is SCL is an Input port which means the clock will come in from the master, so it is  a slave.

please correct me if i am wrong.

Regards

Matt

 
Eliath_G_Intel
Employee
264 Views

Hello Nithin,


Yes, SCL is provided by the master.


SCL is not only the clock, it is also used to receive the acknowledge signal from the slave.


Regards,

-Eliath Guzman


Matt1
Beginner
251 Views

hello Eilath,

yes the clock should be supplied from the master,

here is my point ,when we route the I2C from HPS to FPGA we have the following signals available

Matt1_0-1603170039215.png

since SCL signal is specified as input , then it can only receive the clock, it cannot drive any clock!!

So what I understand from the port list is that, the IP is a slave.

I am looking for the Master I2C from HPS ,accessible to  FPGA to connect to a slave in FPGA.

*I think, SDA signal receive the acknowledge signal from the slave, not the scl.

 

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