flote21
Advanced Member level 1
Hi guys!
I am trying to interface a FPGA and PIC18FL4520 through an UART. Both chips has the same power supply: 3v3 and there is a direct connection between the FPGA and uc using 2 pcb tracks.
Is it necessary to place a level translataor or some kind of pull up resistor in these lines (TX and RX)? As I told previously, I don't have anything and by default the uC and the FPGA is driving to high level both lines. Then when the communication starts, the pulses are generated, but at the endof the comunication, one of the line (RX_in input to the FPGA) is driving to low level by the FPGA while th uC is driving to high level. It is like the FPGA pin is hang up...But the it is srtange because this interface has been used in other boards with the same FPGA and uC and exactly the same pin connections (2 direct tracks btwen chips) and it was working always...
Any suggestion?
Thanks.
I am trying to interface a FPGA and PIC18FL4520 through an UART. Both chips has the same power supply: 3v3 and there is a direct connection between the FPGA and uc using 2 pcb tracks.
Is it necessary to place a level translataor or some kind of pull up resistor in these lines (TX and RX)? As I told previously, I don't have anything and by default the uC and the FPGA is driving to high level both lines. Then when the communication starts, the pulses are generated, but at the endof the comunication, one of the line (RX_in input to the FPGA) is driving to low level by the FPGA while th uC is driving to high level. It is like the FPGA pin is hang up...But the it is srtange because this interface has been used in other boards with the same FPGA and uC and exactly the same pin connections (2 direct tracks btwen chips) and it was working always...
Any suggestion?
Thanks.