The Ultimate Serial Port

"Your Debug Buddy"
from Mystic Engineering

Debug Buddy



Universal USB Serial Port

USB Serial Port Block diagram
(click for bigger version)

Level Shifters

Two banks of jumper programmable six channel level shifters (74VHCT50s)

  • Jumper 2 controls the left shifter on J14
  • Jumper 3 controls the right level shifter on J15

To configure the level shifter

  • Up translate voltages from 3.3V to 5V (set Jumper to the UP position)
  • Down translate voltages from 5V to 3.3V (set Jumper to the DOWN position)

Debug LEDs


The master clock signal originates from the CBUS0 pin on the FTDI 230. When shipped, this pin is configured to generate a 24Mhz square wave. CBUS0 can also be reconfigured to generate 12Mhz or 6Mhz if desired, using the FT_PROG Windows program available from FTDI.

These clock signals are available on J13's pins:

1 2 3 4 5 6 7
24Mhz 12Mhz 1.5Mhz 750Khz 375Khz 187.5Khz 93.8Khz
12Mhz 6Mhz 750Khz 375Khz 187.5Khz 93.8Khz 46.9Khz
6Mhz 3Mhz 375Khz 187.5Khz 93.8Khz 46.9Khz 23.4Khz

8 9 10 11 12 13 14
46.9Khz 23.4Khz 11.7Khz 5.9Khz 2.9Khz 1.5Khz GND
23.4Khz 11.7Khz 5.9Khz 2.9Khz 1.5Khz 732Hz GND
11.7Khz 5.9Khz 2.9Khz 1.5Khz 732Hz 366Hz GND

Note: clocks are derived from the USB signal, so they are only available when USB is connected.


Powered by USB or external 5V supply