gcp

Hi,

Could someone help us. We are trying to interface a ublox SARA U270 EVK as a DCE modem into a pmod zedboard FPGA board as a DTE . We used the Pmod RS232 module just to have a direct conection to the pmod pins of the zedboard. Since, the ublox SARA U270 is a DB9 male type, we used  the Male-Male DB9 cable converter using the straight-through cable connection in order to have a coonection to the Pmod RS232 and then to the pmod pins of the zedboard. Before connecting to the pmod pins in the zedboard, we checked  first the voltage levels of the output pins in the Pmod RS232 when ublox SARA U270 is only in power (zedboard is not yet connected). Upon checking the voltage using the multi meter device, the Rx pin reading is variable from 3V to 4.20V.  Our understanding also in the pmod pins on the zedboard is that the voltage level allowed is only 3.3V. Through these readings, our undertanding is that the 3.3V pin will received the 4.20V from the ublox SARA U270 that will eventually damage to the pmod pin on the zedboard. Do we have a correct understanding on the issues? If not, can somebody enlighten us? 

Thanks.

Best regards,

glenn