Hi,
in the schematic I can see, that two pins of the ICE40 are connected as RxD and TxD to the FTDI chip. Is this a serial interface to communicate the FPGA?
If yes: how do I connect to on PC side? The FTDI did not appear as /dev/tty* device on my Linux machine.
-RRC
I’m not sure how to do it, however my intuition is that you need to make the serial port actually do something. Looking at the code in au_top.luc (it should be similar enough to cu_top.luc) it looks like by default it simply echos the incoming serial data making the computer that it’s connected to think that its not actually connected to anything worth sending data to.
I did some research: The FTDI can be controlled via the libftdi library. For quick and dirty stuff there is also a python package called pylibftdi that is based on the library.
The FTDI has two interfaces A to flash the Cu and B to communicate with the FPGA.
So the Device has to be initalized as follows (in python):
[code]from pylibftdi import Device
device = Device(interface_select=2)
[/code]
Then I was able to send/receive to/from the FPGA with the read() and write() methods.
The baudrate can be changed with
device.baudrate = 300to 300 Baud in this example.
The Python package is documented at https://pylibftdi.readthedocs.io/en/0.15.0/pylibftdi.html
And the library at https://www.intra2net.com/en/developer/libftdi/documentation/