last updated: 2025-01-10
I want to communicate from my PC with an FPGA over a normal serial interface with high bitrates. With USB high bitrates are possible but up to 12 Mbit/s?
I tested some USB/serial adapter and could get 3 MBit/s with some. To get higher bitrates I needed a cable with an high speed chip from FTDI (FT2232H). I found an FTDI cable with this chip called C232HM-EDHSL-0
at reichelt.de.
I connected my oscilloscope to the orange cable (black is GND).
I use this cable under Linux (Kubuntu 24.10) with no special driver needed. A test with a modem program was difficult, because a custom bitrate over 10 Mbit/s was not possible. So I used Python with the following code:
#!/usr/bin/env python
import serial
from time import sleep
SER_PORT = "/dev/ttyUSB0" # check with 'sudo dmesg'
SER_SPEED = 12000000
ser = serial.Serial(SER_PORT, SER_SPEED) # open the serial port
for i in range(1000000):
data = [85,85] # "UU", 0b0101010101010101
data2 = bytearray(data)
ser.write(data2)
sleep(0.000001)
ser.close()