FPGA remapping i2c Pins


To expand the functionality of the LimeMini i want to use the FPGA I2C bus. When i build and flash the default gateware in Quartus it’s possible to probe the signal on the un-populated LM75 pads with a scope.

Because the pins are pretty small i’m almost certain to mess up when trying to solder to them, i thought remapping them to the EGPIO pins would be a option. What i did was in the Quartus pin planner un-assing the FPGA_EGPIO 1/2 from D6 and B7 and remapped FPGA_I2C_SCL and SDA to these pins.



Compiled the project and Flashed LimeSDR-Mini_GW/LimeSDR-Mini_lms7_bitstreams/LimeSDR-Mini_lms7_trx_HW_1.2_auto.rpd (using the LimeSuiteGUI)

Now the quicktest fails on the eeprom read and no more signal on the LM75 pads, both just like expected. So far so good. All that would be missing are 2pcs 1k pull-up resistors from 3.3V to the SCL and SDA line now assigned to the EGPIO pads. These would do the function R64 and R66 in the original design.

Placed these, connected the scope, run quicktest and :…no signal on the scope :frowning:
Who can point me to which steps i missed or messed up here? Or is it just i need a USB-Blaster to flash the new gateware?