I2C 'functions' with LEDs, not with PMODA port

Altera_Forum · ‎08-17-2016

I'd like to use the I2C interface so I used the 'I2C Master'in Qsys.

I route the SCL and SDA outputs of the core to two GPIO pins of the

PMODA connector of my Max 10 Development Kit board. This does not work.

Nooutput from the pins at all.

Strangely enough, if I replace the two pins by twoon board LEDS

the latter light up, indicating that there are SCL and SDAsignals

getting generated.

Any idea how to get the PMODA working? I checked PMODA

independently with almost the same setup and it works fine.

This is the LED-code in the Verilog-file:

.i2c_opencores_0_export_sda_pad_io (USER_LED[2])

.i2c_opencores_0_export_scl_pad_io(USER_LED[3])

And of course very similar for the PMODA port:

.i2c_opencores_0_export_sda_pad_io(PMODA_IO[6])

.i2c_opencores_0_export_scl_pad_io (PMODA_IO[7])

Thanks in advance,

Jos

Altera_Forum · ‎08-17-2016

You may want to add pull-up resistors to the sda and scl pins.

Altera_Forum · ‎08-17-2016

Thanks! When I read your reply I was just busy doing this and it works.

That is, I see activity on the pins. Now I can continue to work on the

I2C expander I use the I2C signals for.

Jos